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Maintenance Testing Specifications
for
Electric Power Distribution
Equipment and Systems
These specifications have been developed

by the
InterNational Electrical Testing Association
for use by
electrical power distribution system engineers.
Copyright 1997
P.O. Box 687, 106 Stone Street
Morrison, CO 80465
303-697-8441 FAX: 303-697-8431
E-mail: neta@compuserve.com
NETA Technical Committee

These specifications were prepared by the NETA Technical Committee. At the time these specifications
were approved, the contributors to this Committee were
Alan D. Peterson, Chair
Charles Blizard
Rafael Castro
Glen Chynoweth
Tim Cotter
Larry Christodoulou
Herb Foster
Diane Hageman
Roderic Hageman
Vern Hegg
Bob Hettchen
Jeffrey J. Hopper
Fredi Jakob
Thomas G. Kunz
Mark Lautenschlager
Richard R. Lussier, Jr.
Al Marden
Charles Potter
Keith Robertson
Richard Sobhraj
Sandy Svatos
John Snell
David Volz
NETA Standards Review Council

Charles K. Blizard
Diane W. Hageman
Alan D. Peterson, Chair

Roderic L. Hageman
Mark Lautenschlager
Mary R. Jordan
NOTICE
In no event shall the InterNational Electrical Testing Association be liable to anyone for special, collateral,
incidental, or consequential damages in connection with or arising out of the use of these materials. This document should
not be confused with federal, state, or municipal specifications or regulations, insurance requirements, or national safety
codes. While the Association recommends reference to or use of this document by government agencies and others, use
of this document is purely voluntary and not binding.
This document is subject to periodic review, and users are cautioned to obtain the latest edition. Comments and
suggestions are invited from all users for consideration. All questions or other communications relating to this document
should be sent only to NETA headquarters, addressed to the attention of the appropriate section.
For information on the procedures for requesting Formal Interpretations, proposing Tentative Interim
Amendments, proposing amendments for consideration, and appeals on matters relating to the content of the document,
write to Secretariat, Standards Review Council, InterNational Electrical Testing Association. A statement, written or oral,
that is not processed in accordance with NETA Operating Procedures for Standards Accreditation shall not be considered
the official position of NETA or any of its Section Panels and shall not be considered to be, nor relied upon as, a Formal
Interpretation.
Mary R. Jordan, EdD - Executive Director

Jayne M. Hudson - Executive Assistant
InterNational Electrical Testing Association (NETA)
PO Box 687/106 Stone St. Morrison, CO 80465 303-697-8441 fax 697-8431 neta@compuserve.com
PREFACE
It is recognized by the Association that the needs of commercial and industrial power system
owners vary widely. Many criteria are used in determining what equipment is to be tested, at what
intervals, and to what extent. Ambient conditions, availability of down time, and maintenance budgets
are but a few of the considerations that go into the planning of a maintenance schedule. The owner,
with the assistance of a reputable electrical testing firm, must make many decisions each time
maintenance is considered.
It is the intent of this document to list a majority of the field tests available for assessing the
suitability for continued service and reliability of the power distribution system. Certain tests have
been assigned an "optional" classification. The following considerations were used in determining the
use of the "optional" classification:
1.
Did another test that was listed provide similar information?
2.
How did the cost of the test compare to the cost of other tests providing similar
information?
3.
How commonplace was the test procedure? Is it new technology?
4.
Did the down time required for the particular test greatly increase that required for the
remainder of the maintenance?
While acknowledging the above, it is still necessary to make an informed judgment for each
particular system regarding how extensive a procedure is justified. The approach taken in these
specifications is to present a comprehensive series of tests that are applicable to most industrial and
larger commercial systems. Even in those cases it is necessary to decide how far "down" into the
system the testing should be taken. In smaller systems some of the tests can be deleted. In other
cases a number of the tests indicated as optional should be performed. The guidance of an
experienced testing professional should be sought when making such decisions.
As a further note, it is important to follow the recommendations contained in the
manufacturer's instruction manuals. Many of the details of a complete and effective maintenance
testing procedure can only be obtained from that source.
The Association encourages comment from users of this document. Please contact the NETA
office or your local NETA member firm.
Alan D. Peterson
NETA Technical Committee Chair
CONTENTS
ELECTRICAL MAINTENANCE TESTS
1.
2.
3.
4.
5.
6.
7.
GENERAL SCOPE .................................................................................................................... 1

APPLICABLE REFERENCES.................................................................................................... 2
QUALIFICATIONS OF TESTING FIRM ..................................................................................... 7
DIVISION OF RESPONSIBILITY ............................................................................................... 8
GENERAL .................................................................................................................................. 9
5.1
Suitability of Test Equipment ........................................................................................... 9
5.2
Test Instrument Calibration ............................................................................................. 9
5.3
Test Report.................................................................................................................... 10
POWER SYSTEMS STUDIES................................................................................................. 11
6.1
Short-Circuit and Coordination Studies ......................................................................... 11
6.2
Load Flow Studies (Reserved) ...................................................................................... 13
6.3
Stability Studies (Reserved) .......................................................................................... 13
6.4
Switching Transients Studies (Reserved)...................................................................... 13
6.5
Motor Starting Studies (Reserved) ................................................................................ 13
6.6
Harmonic Analysis (Reserved) ...................................................................................... 13
6.7
Ground Mat Studies (Reserved).................................................................................... 13
6.8
Cable Ampacity Studies (Reserved).............................................................................. 13
6.9
Reliability Studies (Reserved)........................................................................................ 13
INSPECTION AND TEST PROCEDURES .............................................................................. 14
7.1
Switchgear and Switchboard Assemblies...................................................................... 14
7.2
Transformers ................................................................................................................. 18
1.
Dry-Type ............................................................................................................. 18
1.
Air-Cooled, 600 V and Below - Small
(167 kVA Single-Phase, 500 kVA 3-Phase, and Smaller)........................ 18
2.
Air-Cooled, All Above 600 Volt and 600 Volt and Below - Large
(Greater than 167 Single-Phase and 500 kVA 3-Phase) ......................... 20
2.
Liquid-Filled ........................................................................................................ 24
3.
Gas/Vapor (Reserved) 27
7.3
Cables ........................................................................................................................... 28
1.
Low-Voltage, 600 V Maximum ............................................................................ 28
2.
Medium-Voltage, 69 kV Maximum ...................................................................... 30
3.
High-Voltage ....................................................................................................... 33
7.4
Metal-Enclosed Busways .............................................................................................. 36
7.5
Switches ........................................................................................................................ 38
1.
Air Switches 38
1.
Low-Voltage........................................................................................................ 38
2.
Medium-Voltage, Metal-Enclosed ....................................................................... 40
3.
High- and Medium-Voltage, Open ...................................................................... 43
2.
Oil Switches: Medium-Voltage....................................................................................... 45
3.
Vacuum Switches: Medium-Voltage............................................................................. 48
4.
SF6 Switches: Medium-Voltage (Reserved) .................................................................. 51
5.
Cutouts (Reserved) ....................................................................................................... 51
7.6
7.7
7.8
7.9
7.10
7.11
7.12
7.13
7.14
7.15
7.16
7.17
7.18
7.19
Circuit Breakers ............................................................................................................. 52

1.
Low-Voltage........................................................................................................ 52
1.
Insulated Case/Molded Case ................................................................... 52
2.
Power....................................................................................................... 55
2.
Medium-Voltage.................................................................................................. 58
1.
Air............................................................................................................. 58
2.
Oil............................................................................................................. 61
3.
Vacuum.................................................................................................... 65
4.
SF6 ........................................................................................................... 68
3.
High-Voltage ....................................................................................................... 71
1.
Oil............................................................................................................. 71
2.
SF6 ........................................................................................................... 75
4.
Extra-High-Voltage (Reserved)........................................................................... 77
Circuit Switchers............................................................................................................ 78
Network Protectors, 600 V Class................................................................................... 80
Protective Relays........................................................................................................... 84
Instrument Transformers ............................................................................................... 91
Metering ........................................................................................................................ 94
Regulating Apparatus .................................................................................................... 95
1.
Voltage................................................................................................................ 95
1.
Step Voltage Regulators .......................................................................... 95
2.
Induction Voltage Regulators ................................................................. 100
2.
Current (Reserved) ........................................................................................... 103
3.
Load Tap-Changers.......................................................................................... 104
Grounding Systems ..................................................................................................... 107
Ground-Fault Protection Systems ............................................................................... 108
Rotating Machinery...................................................................................................... 111
1.
Motors............................................................................................................... 111
1.
AC Motors .............................................................................................. 111
2.
DC Motors .............................................................................................. 115
2.
Generators (Reserved) ..................................................................................... 116
Motor Control............................................................................................................... 117
1.
Motor Starters ................................................................................................... 117
1.
Low-Voltage ........................................................................................... 117
2.
Medium-Voltage ..................................................................................... 120
2.
Motor Control Centers ...................................................................................... 124
1.
Low-Voltage ........................................................................................... 124
2.
Medium-Voltage ..................................................................................... 124
Variable Speed Drive (Reserved) ................................................................................ 124
Direct-Current Systems ............................................................................................... 125
1.
Batteries............................................................................................................ 125
2.
Chargers ........................................................................................................... 127
3.
Rectifiers (Reserved) ........................................................................................ 127
Surge Arresters ........................................................................................................... 128
1.
Low-Voltage Surge Protection Devices ............................................................ 128
2.
Medium- and High-Voltage Surge Protection Devices...................................... 130
7.20
8.
9.
Capacitors and Reactors ............................................................................................. 132

1.
Capacitors......................................................................................................... 132
2.
Capacitor Control Devices (Reserved) ............................................................. 133
3.
Reactors (Reserved)......................................................................................... 133
7.21 Outdoor Bus Structures ............................................................................................... 134
7.22 Emergency Systems.................................................................................................... 136
1.
Engine Generator ............................................................................................. 136
2.
Uninterruptible Power Systems......................................................................... 137
3.
Automatic Transfer Switches ............................................................................ 140
7.23 Telemetry/Pilot Wire/Scada (Reserved) ...................................................................... 142
7.24 Automatic Circuit Reclosers and Line Sectionalizers .................................................. 143
1.
Automatic Circuit Reclosers, Oil/Vacuum ......................................................... 143
2.
Automatic Line Sectionalizers, Oil .................................................................... 146
7.25 Fiber-Optic Cables....................................................................................................... 148
7.26 Electrical Safety Equipment......................................................................................... 149
7.27 Electrostatic/Electromagnetic Field Testing (Reserved) .............................................. 150
7.28 Special Systems (Reserved) ....................................................................................... 150
SYSTEM FUNCTION TESTS ................................................................................................ 151
THERMOGRAPHIC SURVEY................................................................................................ 152
10.
10.1
10.2
10.3
10.4
10.5
10.6
10.7
10.8
10.9
10.10
10.11
10.12
10.13
10.14
10.15
10.16
10.17
10.18
10.19
TABLES
Insulation-Resistance Tests on Electrical Apparatus & Systems ................................ 153
Switchgear Low-Frequency Withstand Test Voltages ................................................. 154
Recommended Dissipation Factor/Power Factor of Liquid-Filled Transformers ......... 155
Suggested Limits for Service-Aged Liquids ................................................................. 156
Transformer Insulation-Resistance.............................................................................. 157
Medium-Voltage Cables,Maximum Field Maintenance Test Voltages (kV, dc) ........... 158
Molded-Case Circuit Breakers, Values for Inverse Time Trip Test.............................. 160
Instantaneous Trip Setting Tolerances
for Field Testing of Marked Adjustable Trip Circuit Breakers ...................................... 161
Instrument Transformer Dielectric Tests, Field Maintenance ...................................... 162
Maximum Allowable Vibration Amplitude .................................................................... 163
Periodic Electrical Test Values for Insulating Aerial Devices
Insulating Aerial Devices with a Lower Test Electrode System (A,B) ............... 164
Insulating Aerial Devices without Lower Test Electrode System (C) ................ 164
Insulating Aerial Ladders and Insulating Vertical Aerial Towers ....................... 164
Chassis Insulating Systems Lower Insulated Booms ....................................... 165
Bolt Torques for Bus Connections
Heat-Treated Steel - Cadmium or Zinc Plated.................................................. 166
Silicon Bronze Fasteners.................................................................................. 166
Aluminum Alloy Fasteners ................................................................................ 167
Stainless Steel Fasteners ................................................................................. 167
SF6 Gas Tests ............................................................................................................. 168
Insulation Resistance Conversion Factors
For Conversion of Test Temperature to 20C ............................................................. 169
High-Potential Test Voltage for Automatic Circuit Reclosers....................................... 170
High-Potential Test Voltage for Periodic Test of Line Sectionalizers........................... 171
Metal-Enclosed Bus Dielectric Withstand Test Voltages............................................. 172
Thermographic Survey Suggested Actions Based on Temperature Rise ................... 173
Overpotential Test Voltages for Electrical Apparatus
Other than Inductive Equipment .................................................................................. 174
Standard Specification Form

Electrical Maintenance Tests
1.
GENERAL SCOPE
1.1
The owner shall engage the services of a recognized independent testing firm or
independent electrical consulting firm to perform short-circuit and coordination studies
as herein specified in Section 6.
1.2
The owner shall engage the services of a recognized independent testing firm for the
purpose of performing inspections and tests as herein specified.
1.3
The testing firm shall provide all material, equipment, labor, and technical supervision to
perform such tests and inspections.
1.4
It is the purpose of these specifications to assure that all tested electrical equipment
and systems are operational and within industry and manufacturer's tolerances.
MTS-1997 1
2.
APPLICABLE REFERENCES
2.1
All inspections and field tests shall be in accordance with the latest edition of the
following codes, standards, and specifications except as provided otherwise herein.
1.
American National Standards Institute - ANSI
2.
American Society for Testing and Materials - ASTM

ANSI/ASTM D 92-90. Test Method for Flash and Fire Points by Cleveland Open
Cup
ANSI/ASTM D 445-94. Test Method for Kinematic Viscosity of Transparent and
Opaque Liquids
ASTM D 664-95. Test Method for Acid Number of Petroleum Products by
Potentiometric Titration
ASTM D 877-87 (R1995). Test Method for Dielectric Breakdown Voltage of
Insulating Liquids using Disk Electrodes
ASTM D 923-91. Test Method for Sampling Electrical Insulating Liquids
ASTM D 924-92. Test Method for A-C Loss Characteristics and Relative
Permittivity (Dielectric Constant) of Electrical Insulating Liquids
ANSI/ASTM D 971-91. Test Method for Interfacial Tension of Oil Against Water
by the Ring Method
ASTM D 974-95. Test Method for Acid and Base Number by Color-Indicator
Titration
ANSI/ASTM D 1298-85 (R1990). Test Method for Density, Relative Density
(Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum
Products by Hydrometer Method
ANSI/ASTM D 1500-91. Test Method for ASTM Color of Petroleum Products
(ASTM Color Scale)
ASTM D 1524-94. Test Method for Visual Examination of Used Electrical
Insulating Oils of Petroleum Origin in the Field
ASTM D 1533-88. Test Methods for Water in Insulating Liquids (Karl Fischer
Reaction Method)
ASTM D 1816-84a (R1990). Test Method for Dielectric Breakdown Voltage of
Insulating Oils of Petroleum Origin Using VDE Electrodes
2 MTS-1997
2.
ASTM D 2029-92. Test Methods for Water Vapor Content of Electrical Insulating
Cases by Measurement of Dew Point
ASTM D 2129-90. Test Method for Color of Chlorinated Aromatic Hydrocarbons
(Askarels)
ASTM D 2284-95. Test Method of Acidity of Sulfur Hexafluoride
ASTM D 2285-85 (R1990). Test Method for Interfacial Tension of Electrical
Insulating Oils of Petroleum Origin Against Water by the Drop-Weight Method
ASTM D 2477-84 (R1990). Test Method for Dielectric Breakdown Voltage and
Dielectric Strength of Insulating Gases at Commercial Power Frequencies
ASTM D 2685-95. Test Method for Air and Carbon Tetrafluoride in Sulfur
Hexafluoride by Gas Chromatography
ASTM D 2759-94. Method for Sampling Gas from a Transformer under Positive
Pressure
ASTM D 3284-90a (R1994). Test Method for combustible Gases in Electrical
apparatus in the Field
ASTM D 3612-95. Test Method of Analysis of Gases Dissolved in Electrical
Insulating Oil by Gas Chromatography
ASTM D 3613-92. Methods of Sampling Electrical Insulating Oils for Gas
Analysis and Determination of Water Content
3.
Association of Edison Illuminating Companies - AEIC
4.
Canadian Standards Association - CSA
5.
Institute of Electrical and Electronic Engineers - IEEE

ANSI/IEEE C2-1997, National Electrical Safety Code
ANSI/IEEE C37-1995, Guides and Standards for Circuit Breakers, Switchgear,
Relays, Substations, and Fuses
ANSI/IEEE C57-1995, Distribution, Power, and Regulating Transformers
ANSI/IEEE C62-1995, Surge Protection
MTS-1997 3
2.
ANSI/IEEE Std. 43-1974 (R1991). IEEE Recommended Practice for Testing
Insulation Resistance of Rotating Machinery
IEEE Std. 48-1996. Standard Test Procedures and Requirements for HighVoltage AC Cable Terminations 2.5kV through 276kV
IEEE Std. 81-1983. IEEE Guide for Measuring Earth Resistivity, Ground
Impedance, and Earth Surface Potentials of a Ground System (Part I)
ANSI/IEEE Std. 81.2-1991. IEEE Guide for Measurement of Impedance and
Safety Characteristics of Large, Extended, or Interconnected Grounding Systems
(Part 2)
ANSI/IEEE Std. 95-1977 (R1991). IEEE Recommended Practice for Insulation
Testing of Large AC Rotating Machinery with High Direct Voltage
IEEE Std. 100-1996. The IEEE Standard Dictionary of Electrical and Electronics
Terms
ANSI/IEEE Std. 141-1993. IEEE Recommended Practice for Electrical Power
Distribution for Industrial Plants (IEEE Red Book.)
ANSI/IEEE Std. 142-1991. IEEE Recommended Practice for Grounding of
Industrial and Commercial Power Systems (IEEE Green Book)
ANSI/IEEE Std. 241-1990. IEEE Recommended Practice for Electric Power
Systems in Commercial Buildings (Gray Book)
ANSI/IEEE Std. 242-1986 (R1991). IEEE Recommended Practice for Protection
and Coordination of Industrial and Commercial Power Systems (Buff Book)
ANSI/IEEE Std. 399-1990. IEEE Recommended Practice for Power Systems
Analysis (Brown Book)
ANSI/IEEE Std. 400-1991. IEEE Guide for Making High-Direct-Voltage Tests on
Power Cable Systems in the Field
ANSI/IEEE Std. 421B-1979. IEEE Standard for High-Potential-Test
Requirements for Excitation Systems for Synchronous Machines
ANSI/IEEE Std. 446-1995. IEEE Recommended Practice for Emergency and
Standby Power Systems for Industrial and Commercial Applications (Orange
Book)
4 MTS-1997
2.
ANSI/IEEE Std. 450-1994. IEEE Recommended Practice for Maintenance,
Testing, and Replacement of Large Lead Storage Batteries for Generating
Stations and Substations
ANSI/IEEE Std. 493-1990. IEEE Recommended Practice for the Design of
Reliable Industrial and Commercial Power Systems (Gold Book)
ANSI/IEEE Std. 602-1996. IEEE Recommended Practice for Electric Systems in
Health Care Facilities (White Book)
ANSI/IEEE Std. 637-1985 (R1992). IEEE Guide for the Reclamation of Insulating
Oil and Criteria for Its Use
ANSI/IEEE Std. 739-1995. IEEE Recommended Practice for Energy
Conservation and Cost-Effective Planning in Industrial Facilities (Bronze Book)
ANSI/IEEE Std. 1100-1992. IEEE Recommended Practice for Powering and
Grounding Sensitive Electronic Equipment (Emerald Book)
ANSI/IEEE Std. 1106-1995. IEEE Recommended Practice for Maintenance,
Testing, and Replacement of Nickel-Cadmium Storage Batteries for Generating
Stations and Substations
6.
Insulated Cable Engineers Association - ICEA
7.
InterNational Electrical Testing Association - NETA

NETA ATS-95. NETA Acceptance Testing Specifications for Electrical
Power Distribution Equipment and Systems
8.
National Electrical Manufacturer's Association - NEMA

NEMA Standard for Publication No. AB4-1991. Guidelines for Inspection and
Preventive Maintenance of Molded-Case Circuit Breakers Used in Commercial
and Industrial Applications
NEMA Publication MG1-1993. Motors and Generators
9.
National Fire Protection Association - NFPA

ANSI/NFPA 70-1996. National Electrical Code
ANSI/NFPA 70B-1994. Recommended Practice for Electric Equipment
Maintenance
MTS-1997 5
2.
ANSI/NFPA 70E-1995. Electrical Safety Requirements for Employee Workplaces
ANSI/NFPA 99-1993. Standard for Healthcare Facilities
ANSI/NFPA 101-1994. Life Safety Code
ANSI/NFPA 110-1993. Emergency and Standby Power Systems
ANSI/NFPA 780-1995. Installation of Lightning Protection Systems
10.
Occupational Safety and Health Administration - OSHA
11.
Scaffold Industry Association - SIA

ANSI/SIA A92.2-1990. Vehicle Mounted Elevating and Rotating Aerial Devices
12.
State and local codes and ordinances
13.
Underwriters Laboratories, Inc. - UL
6 MTS-1997
3.QUALIFICATIONS OF TESTING FIRM

3.1
The testing firm shall be an independent testing organization which can function as an
unbiased testing authority, professionally independent of the manufacturers, suppliers,
and installers of equipment or systems evaluated by the testing firm.
3.2
The testing firm shall be regularly engaged in the testing of electrical equipment
devices, installations, and systems.
3.3
The testing firm shall meet the criteria for Full Membership or be a Full Member
company of the InterNational Electrical Testing Association.
3.4
The lead, on site, technical person shall hold a current certification in one of the
following:
1.
NETA (InterNational Electrical Testing Association)

Certified Technician/Level III or Certified Senior Technician/Level IV
2.
NICET, (National Institute for Certification in Engineering Technologies)

Engineering Technician/Level III or Senior Engineering Technician/Level IV
specifically in Electrical Testing Technology.
3.5
The testing firm shall utilize technicians who are regularly employed by the firm for
testing services.
3.6
The testing firm shall submit proof of the above qualifications with bid documents when
requested.
MTS-1997 7
4.
DIVISION OF RESPONSIBILITY
4.1
The owner shall supply a suitable and stable source of electrical power to each test site.
The testing firm shall specify the specific power requirements.
4.2
The owner shall notify the testing firm when equipment becomes available for
maintenance tests. Work shall be coordinated to expedite project scheduling.
4.3
The owner shall supply a short-circuit analysis and coordination study, a protective
device setting sheet, a complete set of electrical plans, specifications, and any pertinent
change orders to the testing firm prior to commencement of testing.
4.4
The testing firm shall notify the owner prior to commencement of any testing.
4.5
Any system, material, or workmanship which is found defective on the basis of

maintenance tests shall be reported.
4.6
The testing firm shall maintain a written record of all tests and shall assemble and
certify a final test report.
4.7
Safety and Precautions

1.
8 MTS-1997
Safety practices should include, but are not limited to, the following
requirements:
1.
Current Occupational Safety and Health regulations
2.
National Safety Council, Accident Prevention Manual for Industrial

Operations
3.
Applicable state and local safety operating procedures
4.
Owner's safety practices
5.
ANSI/NFPA 70E, Electrical Safety Requirements for Employee

Workplaces
6.
OSHA 29 CFR 1910.147. Control of Hazardous Energy Sources

(Lockout/Tagout)
2.
All tests shall be performed with apparatus de-energized except where otherwise
specifically required.
3.
The testing organization shall have a designated safety representative on the

project to supervise operations with respect to safety.
5.
GENERAL
5.1
5.2
Suitability of Test Equipment

1.
All test equipment shall be in good mechanical and electrical condition.
2.
Split-core current transformers and clamp-on or tong-type ammeters require

careful consideration of the following in regard to accuracy:
1.
Position of the conductor within the core
2.
Clean, tight fit of the core pole faces
3.
Presence of external fields
4.
Accuracy of the current transformer ratio in addition to the accuracy of the

secondary meter
3.
Selection of metering equipment should be based on a knowledge of the

waveform of the variable being measured. Digital multimeters may be average or
rms sensing and may include or exclude the dc component. When the variable
contains harmonics or dc offset and, in general, any deviation from a pure sine
wave, average sensing, rms scaled meters may be misleading.
4.
Field test metering used to check power system meter calibration must have an
accuracy higher than that of the instrument being checked.
5.
Accuracy of metering in test equipment shall be appropriate for the test being
performed but not in excess of two percent of the scale used.
6.
Waveshape and frequency of test equipment output waveforms shall be

appropriate for the test and the tested equipment.
Test Instrument Calibration

1.
The testing firm shall have a calibration program which assures that all
applicable test instruments are maintained within rated accuracy.
2.
The accuracy shall be directly traceable to the National Institute of Standards

and Technology (NIST).
MTS-1997 9
5.
GENERAL
3.
5.3
Instruments shall be calibrated in accordance with the following frequency

schedule:
1.
Field instruments: Analog, 6 months maximum. Digital, 12 months

maximum
2.
Laboratory instruments: 12 months
3.
Leased specialty equipment: 12 months where accuracy is guaranteed by

lessor
4.
Dated calibration labels shall be visible on all test equipment.
5.
Records, which show date and results of instruments calibrated or tested, must
be kept up-to-date.
6.
Up-to-date instrument calibration instructions and procedures shall be

maintained for each test instrument.
7.
Calibrating standard shall be of higher accuracy than that of the instrument

tested.
Test Report
1.
2.
10 MTS-1997
The test report shall include the following:

1.
Summary of project
2.
Description of equipment tested
3.
Description of test
4.
Test results
5.
Analysis and recommendations
Furnish a copy or copies of the complete report to the owner as required in the
maintenance contract.
6.
POWER SYSTEM STUDIES

6.1
Short-Circuit and Coordination Studies

1.
Scope of Services
1.
Provide a current and complete short-circuit study, equipment-interrupting

or withstand evaluation, and a protective-device coordination study for the
electrical distribution system.
The studies shall include all portions of the electrical distribution system
from the normal and alternate sources of power throughout the lowvoltage distribution system. Normal system operating method, alternate
operation, and operations which could result in maximum-fault conditions
shall be thoroughly covered in the study.
2.
Short-Circuit Study
1.
The study shall be in accordance with applicable ANSI and IEEE

standards.
2.
The study input data shall include the short-circuit single- and three-phase
contributions from all sources, with the X/R ratio, the resistance and
reactance components of each branch impedance, motor and generator
contributions, base quantities selected, and all other applicable circuit
parameters.
3.
Short-circuit momentary duties and interrupting duties shall be calculated

on the basis of maximum available fault current at each switchgear bus,
switchboard, motor control center, distribution panelboard, pertinent
branch circuit panelboards, and other significant locations through the
system.
1.
For the portions of a system utilizing medium- and high-voltage

breakers, separate calculations shall be made for one-half cycle
(close and latch) currents and interrupting currents. Calculations
shall be for three-phase and phase-to-ground faults at each bus
under consideration.
2.
For the portions of a system utilizing low-voltage breakers (less

than 1,000 volts), calculations shall be made for three-phase and
phase-to-ground interrupting currents at each bus under
consideration.
MTS-1997 11
6.

6.1
Short-Circuit and Coordination Studies (cont.)

3.
Equipment Evaluation Study

1.
4.
5.
12 MTS-1997
An equipment evaluation study shall be performed to determine the

adequacy of circuit breakers, controllers, surge arresters, busways,
switches, and fuses by tabulating and comparing the short-circuit ratings
of these devices with the maximum short-circuit momentary and
interrupting duties.
Protective-Device Coordination Study

1.
A protective-device coordination study shall be performed to select or to

verify the selection of power fuse ratings, protective-relay characteristics
and settings, ratios, and characteristics of associated voltage and current
transformers, and low-voltage breaker trip characteristics and settings.
2.
The coordination study shall include all voltage classes of equipment from
the source's incoming line protective device down to and including each
motor control center and/or panelboard. The phase and ground
overcurrent protection shall be included as well as settings for all other
adjustable protective devices.
3.
Protective device selection and settings shall be in accordance with

requirements of the National Electrical Code and the recommendations of
the ANSI/IEEE Standard 399, as applicable.
Study Report
1.
Discrepancies, problem areas, or inadequacies shall be promptly brought

to the owner's attention.
2.
The results of the power-system studies shall be summarized in a final

report.
3.
The report shall include the following sections:

1.
Description, purpose, basis, and scope of the study and a singleline diagram of the portion of the power system which is included
within the scope of study.
2.
Tabulations of circuit breaker, fuse, and other equipment ratings

versus calculated short-circuit duties and commentary regarding
same.
6.

6.1
Short-Circuit and Coordination Studies (cont.)
6.
3.
Protective device coordination curves, with commentary.
4.
The selection and settings of the protective devices shall be

provided separately in a tabulated form listing circuit identification,
IEEE device number, current transformer ratios, manufacturer,
type, range of adjustment, and recommended settings. A tabulation
of the recommended power fuse selection shall be provided for all
fuses in the system.
5.
Fault-current tabulations including a definition of terms and a guide

for interpretation.
Implementation
1.
The owner shall engage an independent testing firm for the purpose of
inspecting, setting, testing, and calibrating the protective relays, circuit
breakers, fuses, and other applicable devices as recommended in the
power-system study report.
6.2
Load Flow Studies - Reserved
6.3
Stability Studies - Reserved
6.4
Switching Transients Studies - Reserved
6.5
Motor Starting Studies - Reserved
6.6
Harmonic Analysis - Reserved
6.7
Ground Mat Studies - Reserved
6.8
Cable Ampacity Studies - Reserved
6.9
Reliability Studies - Reserved
MTS-1997 13
7.
INSPECTION AND TEST PROCEDURES

7.1
Switchgear and Switchboard Assemblies

1.
Visual and Mechanical Inspection

1.
Compare equipment nameplate data with latest one-line diagram when

available.
2.
Inspect physical, electrical, and mechanical condition including evidence

of moisture or corona.
3.
Verify appropriate anchorage, required area clearances, physical damage,

and correct alignment.
4.
Verify that fuse and/or circuit breaker sizes and types correspond to
drawings and coordination study as well as to the circuit breaker's address
for microprocessor-communication packages.
5.
Verify that current and voltage (potential) transformer ratios correspond to

drawings.
6.
Inspect all bus connections for high resistance using one of the following
methods:
7.
8.
14 MTS-1997
1.
Use of low-resistance ohmmeter in accordance with Section 7.1.2.3

(Electrical Tests).
2.
Verify tightness of accessible bolted electrical connections by

calibrated torque-wrench method in accordance with
manufacturer's published data or Table 10.12.
3.
Perform thermographic survey in accordance with Section 9.
Confirm correct operation and sequencing of electrical and mechanical

interlock systems.
1.
Attempt closure on locked-open devices. Attempt to open lockedclosed devices.
2.
Make key exchange with devices operated in off-normal positions.
Thoroughly clean unit prior to testing unless as-found and as-left tests are
required.
7.

7.1
Switchgear and Switchboard Assemblies (cont.)

9.
2.
Inspect insulators for evidence of physical damage or contaminated

surfaces.
10.
Verify correct barrier and shutter installation and operation.
11.
Lubrication
1.
Verify appropriate contact lubricant on moving current-carrying

parts.
2.
Verify appropriate lubrication on moving and sliding surfaces.
12.
Exercise all active components.
13.
Inspect all mechanical indicating devices for correct operation.
14.
Verify that filters are in place and/or vents are clear.
15.
Test operation, alignment, and penetration of instrument transformer

withdrawal disconnects, current-carrying and grounding, in accordance
with Section 7.10.
16.
Inspect for control power transformers.

1.
Inspect for physical damage, cracked insulation, broken leads,

tightness of connections, defective wiring, and overall general
condition.
2.
Verify that primary and secondary fuse ratings or circuit breakers

match drawings.
3.
Verify correct functioning of drawout disconnecting and grounding

contacts and interlocks.
Electrical Tests
1.
Perform tests on all instrument transformers in accordance with Section

7.10.
2.
Perform ground-resistance tests in accordance with Section 7.13.
MTS-1997 15
7.

7.1

3.
Perform resistance measurements through all bus joints with a lowresistance ohmmeter, if applicable, in accordance with Section 7.1.1.6
(Visual and Mechanical Inspection).
4.
Perform insulation-resistance tests on each bus section, phase-to-phase

and phase-to-ground for one minute in accordance with Table 10.1.
*5.
Perform an overpotential test on each bus section, each phase to ground

with phases not under test grounded, in accordance with manufacturer's
published data. If manufacturer has no recommendation for this test, it
shall be in accordance with Table 10.2. The test voltage shall be applied
for one minute. Refer to Section 7.1.3.4 before performing test.
*6.
Perform insulation-resistance tests at 1000 volts dc on all control wiring.

For units with solid-state components, follow manufacturer's
recommendations.
7.
Perform system function tests in accordance with Section 8.
8.
Control Power Transformers
9.
10.
* Optional
16 MTS-1997
1.
Perform insulation-resistance tests. Perform measurements from

winding-to-winding and each winding-to-ground. Test voltages
shall be in accordance with Table 10.1 unless otherwise specified
by manufacturer.
2.
Verify correct function of control transfer relays located in

switchgear with multiple power sources.
Voltage (Potential) Transformers

1.
Perform insulation-resistance tests. Perform measurements from

winding-to-winding and each winding-to-ground. Test voltages
shall be in accordance with Table 10.1 unless otherwise specified
by manufacturer.
2.
Verify secondary voltages.
Verify operation of switchgear/switchboard heaters.
7.

7.1

3.
Test Values
1.
Compare bus connection resistances to values of similar connections.
2.
Bolt-torque levels shall be in accordance with Table 10.12 unless

otherwise specified by manufacturer.
3.
Microhm or millivolt drop values shall not exceed the high levels of the
normal range as indicated in the manufacturer's published data. If
manufacturer's data is not available, investigate any values which deviate
from similar bus by more than 25 percent of the lowest value.
4.
Insulation-resistance values for bus, control wiring, and control power

transformers shall be in accordance with manufacturer's published data.
In the absence of manufacturer's published data, use Table 10.1. Values
of insulation resistance less than this table or manufacturer's minimum
should be investigated. Overpotential tests should not proceed until
insulation-resistance levels are raised above minimum values.
5.
The insulation shall withstand the overpotential test voltage applied.
MTS-1997 17
7.

7.2
Transformers
1.
Dry Type
1.
Air-Cooled, 600 Volt and Below - Small
(167 kVA Single-Phase, 500 kVA 3-Phase, and Smaller)
1.
2.
* Optional
18 MTS-1997
Visual and mechanical inspection.

1.
Inspect physical and mechanical condition.
2.
required.
3.
Inspect all bolted electrical connections for high resistance using one of
the following methods:
1.
Use of low-resistance ohmmeter in accordance with Section

7.2.1.1.2.1 (Electrical Tests).
2.

3.
Electrical Tests
1.
Perform resistance measurements through all bolted connections with a

low-resistance ohmmeter, if applicable, in accordance with Section
7.2.1.1.1.3 (Visual and Mechanical Inspection).
2.
Perform insulation-resistance tests winding-to-winding and each

winding-to-ground with test voltage in accordance with Table 10.5.
Calculate polarization index.
*3.
Perform turns ratio tests at the designated tap position.
*4.
Verify that as-left tap connections are as specified.
7.

7.2
Transformers
1.
Dry Type
1.
Air-Cooled, 600 Volt and Below - Small
(167 kVA Single-Phase, 500 kVA 3-Phase, and Smaller) (cont.)
3.
Test Values
1.
Compare bolted connection resistances to values of similar connections.
2.

3.
from similar connections by more than 25 percent of the lowest value.
4.
Insulation-resistance test values at one minute should not be less than

values recommended in Table 10.5. Results shall be temperature
corrected in accordance with Table 10.14.
5.
The polarization index should be compared to previously obtained results.
6.
Turns-ratio test results should not deviate more than one-half percent
from either the adjacent coils or the calculated ratio.
MTS-1997 19
7.

7.2
Transformers (cont.)
1.
Dry-Type (cont.)
2.
Air-Cooled, All Above 600 Volt and
600 Volt and Below - Large
(Greater than 167 Single-Phase and 500 kVA 3-Phase)
1.

1.
*2.
20 MTS-1997
Verify that control and alarm settings on temperature indicators are as

specified.
3.
Verify that cooling fans operate.
4.
1.

2.

3.
5.
Perform specific inspections and mechanical tests as recommended by

manufacturer.
6.
Verify that resilient mounts are free and that any shipping brackets have
been removed.
7.
Verify that the core, frame, and enclosure are grounded.
8.
Verify the presence of transformer surge arresters.
9.
required.
10.
* Optional
Inspect physical, electrical, and mechanical condition including evidence

of moisture, corona, or brittleness.
Verify that as-left tap connections are as specified.
7.

7.2
1.
Dry Type (cont.)
2.
(Greater than 167 kVA Single-Phase and 500 kVA 3-Phase) (cont.)
2.
Electrical Tests
1.
Perform insulation-resistance tests winding-to-winding and each

winding-to-ground, with test voltage in accordance with Table 10.5.
2.

3.
Perform power-factor or dissipation-factor tests in accordance with the

test equipment manufacturer's published data.
4.
Perform turns-ratio tests at the designated tap position.
*5.
Perform an excitation-current test on each phase.
*6.
Measure the resistance of each winding at the designated position.
7.
*8.
Measure core insulation-resistance at 500 volts dc if core is insulated and

if the core ground strap is removable.
Perform an overpotential test on all high- and low-voltage windings-toground.
NOTE: Field dielectric tests may be warranted in specific circumstances.
However periodic dielectric tests are not recommended because of the
severe stress imposed on the insulation. (ANSI/IEEE C57.12.91, Section
10.2.
9.
Verify correct secondary voltage phase-to-phase and phase-to-neutral

after energization and prior to loading.
* Optional
MTS-1997 21
7.

7.2
1.
Dry Type (cont.)
2.
3.
Test Values
1.
2.

3.
4.

values recommended in Table 10.5. Results shall be temperature
5.
6.
Turns-ratio test results should not deviate more than one-half percent
from either the adjacent coils or the calculated ratio.
7.
CH and CL dissipation-factor/power-factor values will vary due to support

insulators and bus work utilized on dry transformers. The following should
be expected on CHL power factors:
Power Transformers: two percent or less
Distribution Transformers: five percent or less
Consult transformer manufacturer's or test equipment manufacturer's data
for additional information.
22 MTS-1997
8.
Winding-resistance test results should compare within one percent of

previously obtained results after factoring in temperature correction.
9.
Typical excitation current test data pattern for three-legged core

transformer is two similar current readings and one lower current reading.
7.

7.2
1.
Dry Type (cont.)
2.
10.
Core insulation resistance values should be comparable to previously

obtained results but not less than one megohm at 500 volts dc.
11.
AC overpotential test shall not exceed 65 percent of factory test voltage

for one minute duration.
DC overpotential test shall not exceed 100 percent of the factory rms test
voltage for one minute duration. The insulation shall withstand the
overpotential test voltage applied.
MTS-1997 23
7.

7.2
2.
Liquid-Filled
1.

1.
*2.
3.
* Optional
24 MTS-1997

Verify that alarm, control, and trip settings on temperature indicators are
as specified.
Verify that cooling fans and/or pumps operate correctly.
*4.
Verify operation of all alarm, control, and trip circuits from temperature
and level indicators, pressure relief device, and fault pressure relay.
5.
1.

7.2.2.2.2 (Electrical Tests).
2.

3.
6.
Verify correct liquid level in all tanks and bushings.
7.
Verify that positive pressure is maintained on nitrogen-blanketed

transformers.
8.

manufacturer.
9.
Verify correct equipment grounding.
10.
Test load tap-changer in accordance with Section 7.12, if applicable.
11.
Verify the presence of transformer surge arresters.
7.

7.2
2.
Liquid-Filled (cont.)
2.
Electrical Tests
1.
Perform insulation-resistance tests, winding-to-winding and each

winding-to-ground, with test voltage in accordance with Table 10.5. Test
duration shall be for ten minutes with resistances tabulated at 30 seconds,
one minute, and ten minutes. Calculate polarization index.
2.

7.2.2.1.5 (Visual and Mechanical Inspection).
3.
Perform turns-ratio tests at the designated tap position.
4.
Perform insulation power-factor/dissipation-factor tests on all windings

and correct to 20C in accordance with test equipment manufacturer's
published data.
5.
Perform power-factor/dissipation-factor tests (or hot collar watts-loss tests)

on bushings and correct for 20C in accordance with test equipment
manufacturer's published data.
*6.
Perform excitation-current tests in accordance with test equipment

7.
Measure the resistance of each winding at the designated tap position.
*8.
If core ground strap is accessible, measure core insulation resistance at

500 volts dc.
*9.
Measure the percentage of oxygen in the nitrogen gas blanket, if

applicable.
* Optional
MTS-1997 25
7.

7.2
2.
10.
Remove a sample of insulating liquid in accordance with ASTM D923.

Sample shall be tested in accordance with the referenced standard.
1.
Dielectric breakdown voltage: ASTM D877 and/or ASTM D1816
2.
Acid neutralization number: ANSI/ASTM D974
*3.
11.
3.
* Optional
26 MTS-1997
Specific gravity: ANSI/ASTM D1298
4.
Interfacial tension: ANSI/ASTM D971 or ANSI/ASTM D2285
5.
Color: ANSI/ASTM D1500
6.
Visual Condition: ASTM D1524
*7.
Parts per million water: ASTM D1533. Required on 25 kV or higher

voltages and on all silicone-filled units.
*8.
Measure dissipation factor or power factor in accordance with

ASTM D924.
Remove a sample of insulating liquid in accordance with ASTM D3613

and perform dissolved gas analysis (DGA) in accordance with ANSI/IEEE
C57.104 or ASTM D3612.
Test Values
1.
2.

3.
7.

7.2
2.
3.
4.

values recommended in Table 10.5. Resistance values to be temperature
5.
6.
Turns-ratio test results shall not deviate more than one-half percent from
either the adjacent coils or the calculated ratio.
7.
Maximum power factor of liquid-filled transformers corrected to 20C shall

be in accordance with transformer manufacturer's published data.
Representative values are indicated in Table 10.3. Compare with test
equipment manufacturer's published data.
8.
Investigate bushing power factors and capacitances that vary from

nameplate values by more than ten percent. Investigate any bushing hot
collar watts-loss results that exceed the test equipment manufacturer's
published data.
9.
Typical excitation-current test data pattern for three-legged core

transformer is two similar current readings and one lower current reading.
10.
Winding-resistance measurements should compare within one percent of

previously obtained results after factoring in temperature correction.
11.
Core insulation values should be comparable to previously obtained

results but not less than one megohm at 500 volts dc.
12.
Investigate presence of oxygen in nitrogen gas blanket.
13.
Insulating liquid shall be in accordance with Table 10.4.
14.
Evaluate results of dissolved-gas analysis in accordance with ANSI/IEEE

Standard C57.104.
Gas/Vapor - Reserved
MTS-1997 27
7.

7.3
Cables
1.
Low-Voltage, 600 Volt Maximum
1.

1.
Inspect exposed sections of cables for physical damage and evidence of

overheating.
2.
3.
2.
28 MTS-1997
1.

2.

3.
Inspect compression-applied connectors for correct cable match and

indentation.
Electrical Tests
1.
Perform insulation-resistance tests on each cable phase-to-phase and

phase-to-ground. Applied potential to be 1000 volts dc for one minute.
2.

7.

7.3
Cables (cont.)
1.
Low-Voltage, 600 Volt Maximum (cont.)
3.
Test Values
1.
2.

otherwise specified by the manufacturer.
3.
4.
Minimum insulation-resistance values should be comparable to previously

obtained results but not less than two megohms.
5.
Investigate deviations between adjacent phases.
MTS-1997 29
7.

7.3
Cables (cont.)
2.
Medium-Voltage, 69 kV Maximum
1.
2.

1.

overheating and corona.
2.
Inspect terminations and splices for evidence of overheating and corona.
3.
2.

3.
4.

indentation.
5.
Inspect for shield grounding, cable support, and termination.
6.
Verify that visible cable bends meet or exceed ICEA and/or

manufacturer's minimum allowable bending radius.
7.
Inspect fireproofing in common cable areas, if specified.
8.
If cables are terminated through window-type current transformers, make

an inspection to verify that neutral and ground conductors are correctly
placed and that shields are correctly terminated for operation of protective
devices.
Electrical Tests
1.
30 MTS-1997
1.
Perform a shield-continuity test on each power cable by ohmmeter

method.
7.

7.3
Cables (cont.)
2.
Medium-Voltage, 69 kV Maximum (cont.)
2.
Perform an insulation-resistance test utilizing a megohmmeter with a

voltage output of at least 2500 volts. Individually test each conductor with
all other conductors and shields grounded. Test duration shall be one
minute.
3.

4.
Perform a dc high-potential test on all cables. Adhere to all precautions

and limits as specified in the applicable NEMA/ICEA Standard for the
specific cable. Perform tests in accordance with ANSI/IEEE Standard 400.
Test procedure shall be as follows, and the results for each cable test
shall be recorded as specified herein. Test voltages shall not exceed 60
percent of cable manufacturer's factory test value or the maximum test
voltage in Table 10.6.
1.
Insure that the input voltage to the test set is regulated.
2.
Current-sensing circuits in test equipment shall measure only the

leakage current associated with the cable under test and shall not
include internal leakage of the test equipment.
3.
Record wet- and dry-bulb temperatures or relative humidity and

temperature.
4.
Test each section of cable individually.
5.
Individually test each conductor with all other conductors grounded.

Ground all shields.
6.
Terminations shall be adequately corona-suppressed by guard ring,

field reduction sphere, or other suitable methods as necessary.
7.
Insure that the maximum test voltage does not exceed the limits for
terminators specified in ANSI/IEEE Standard 48 or manufacturer's
specifications.
MTS-1997 31
7.

7.3
Cables (cont.)
2.
Medium-Voltage, 69 kV Maximum (cont.)
3.
32 MTS-1997
Apply a dc high-potential test in at least five equal increments until

maximum test voltage is reached. No increment shall exceed the
voltage rating of the cable. Record dc leakage current at each step
after a constant stabilization time consistent with system charging
current.
9.
Raise the conductor to the specified maximum test voltage and

hold for five minutes. Record readings of leakage current at 30
seconds and one minute and at one minute intervals thereafter.
10.
Reduce the conductor test potential to zero and measure residual

voltage at discrete intervals.
11.
Apply grounds for a time period adequate to drain all insulation

stored charge.
Test Values
1.
2.

3.
4.
Shielding must exhibit continuity. Investigate resistance values in excess

of ten ohms per 1000 feet of cable.
*5.
* Optional
8.
Graphic plots may be made of leakage current versus step voltage at

each increment and leakage current versus time at final test voltages.
6.
The step voltage slope should be reasonably linear.
7.
Capacitive and absorption current should decrease continually until

steady state leakage is approached.
8.
Compare test results to previously obtained results.
7.

7.3
Cables (cont.)
3.
High-Voltage
1.
2.

1.

overheating and corona.
2.
Inspect terminations and splices for evidence of overheating and corona.
3.
1.

2.

3.
4.

indentation.
5.
Inspect for shield grounding, cable support, and termination.
6.
Verify that visible cable bends meet or exceed ICEA and/or

manufacturer's minimum allowable bending radius.
7.
Inspect fireproofing in common cable areas, if specified.
8.
If cables are terminated through window-type current transformers, make

an inspection to verify that neutral and ground conductors are correctly
placed and that shields are correctly terminated for operation of protective
devices.
Electrical Tests
1.
Perform a shield-continuity test on each power cable by ohmmeter

method.
MTS-1997 33
7.

7.3
Cables (cont.)
3.
High-Voltage (cont.)
34 MTS-1997
2.
Perform an insulation-resistance test utilizing a megohmmeter with a

voltage output of at least 2500 volts. Individually test each conductor with
all other conductors and shields grounded. Test duration shall be one
minute.
3.

4.
Perform a dc high-potential test on all cables. Adhere to all precautions

and limits as specified in the applicable NEMA/ICEA Standard for the
specific cable. Perform tests in accordance with ANSI/IEEE Standard 400.
Test procedure shall be as follows, and the results for each cable test
shall be recorded as specified herein. Test voltages shall not exceed 60
percent of cable manufacturer's factory test value or the maximum test
voltage in Table 10.6.
1.
Insure that the input voltage to the test set is regulated.
2.
Current-sensing circuits in test equipment shall measure only the

leakage current associated with the cable under test and shall not
include internal leakage of the test equipment.
3.
Record wet- and dry-bulb temperatures or relative humidity and

temperature.
4.
Test each section of cable individually.
5.
Individually test each conductor with all other conductors grounded.

Ground all shields.
6.
Terminations shall be adequately corona-suppressed by guard ring,

field reduction sphere, or other suitable methods as necessary.
7.
Insure that the maximum test voltage does not exceed the limits for
terminators specified in ANSI/IEEE Standard 48 or manufacturer's
specifications.
7.

7.3
Cables (cont.)
3.
3.
8.
Apply a dc high-potential test in at least five equal increments until

maximum test voltage is reached. No increment shall exceed the
voltage rating of the cable. Record dc leakage current at each step
after a constant stabilization time consistent with system charging
current.
9.
Raise the conductor to the specified maximum test voltage and

hold for five minutes. Record readings of leakage current at 30
seconds and one minute and at one minute intervals thereafter.
10.
Reduce the conductor test potential to zero and measure residual

voltage at discrete intervals.
11.
Apply grounds for a time period adequate to drain all insulation

stored charge.
Test Values
1.
2.

3.
4.
Shielding must exhibit continuity. Investigate resistance values in excess

of ten ohms per 1000 feet of cable.
*5.
Graphic plots may be made of leakage current versus step voltage at

each increment and leakage current versus time at final test voltages.
6.
The step voltage slope should be reasonably linear.
7.
Capacitive and absorption current should decrease continually until

steady state leakage is approached.
8.
Compare test results to previously obtained results.
* Optional
MTS-1997 35
7.

7.4
Metal-Enclosed Busways
1.
2.
36 MTS-1997

1.
Inspect busway for physical damage and evidence of corona.
2.
Inspect for appropriate bracing, suspension, alignment, and enclosure

ground.
3.
1.
Use of low-resistance ohmmeter in accordance with Section 7.4.2.3

(Electrical Tests).
2.
Verify tightness of accessible bolted electrical connections and bus

joints by calibrated torque-wrench method in accordance with
3.
4.
Confirm physical orientation in accordance with manufacturer's labels to

insure adequate cooling.
5.
Examine outdoor busway for removal of "weep-hole" plugs, if applicable,

and the correct installation of joint shield.
6.
Inspect and clean all ventilating openings.
Electrical Tests
1.
Measure insulation resistance of each busway, phase-to-phase and

phase-to-ground for one minute, in accordance with Table 10.1.
2.
Perform an overpotential test on each busway, phase-to-ground with

phases not under test grounded, in accordance with Table 10.17. Where
no dc test value is shown in Table 10.17, ac value shall be used. The test
voltage shall be applied for one minute.
3.
Perform resistance measurements through all bolted connections and bus

joints with a low-resistance ohmmeter, if applicable, in accordance with
Section 7.2.1.3 (Visual and Mechanical Inspection).
4.
Verify operation of busway heaters.
7.

7.4
Metal-Enclosed Busways (cont.)

3.
Test Values
1.
Compare bolted connection resistances and bus joint resistances to

values of similar connections.
2.

3.
from similar bus joints and connections by more than 25 percent of the
lowest value.
4.
Insulation-resistance test voltages and resistance values shall be in

accordance with manufacturer's specifications or Table 10.1. Minimum
resistance values are for a nominal 1000-foot busway run or megohms for
1000 feet. For busway runs over 1000 feet, derate accordingly by the
formula:
R1000 ft = Measured Re sis tan ce x
Length of Run
1000
Values of insulation resistance less than this table or manufacturer's

minimum should be investigated. Overpotential tests should not proceed
until insulation-resistance levels are raised above minimum values.
5.
MTS-1997 37
7.

7.5
Switches
1.
Air Switches
1.
Low-Voltage
1.
38 MTS-1997

1.
2.
Verify appropriate anchorage and required area clearances.
3.
Verify appropriate equipment grounding.
4.
Verify correct blade alignment, blade penetration, travel stops, and

mechanical operation.
5.
Verify that fuse sizes and types are in accordance with drawings and
short-circuit and coordination studies.
6.
Verify that each fuse holder has adequate mechanical support.
7.
1.

2.

3.
8.
Test all interlocking systems for correct operation and sequencing.
9.
Inspect insulating assemblies for evidence of physical damage or

contaminated surfaces.
10.
11.
Verify all indicating and control devices.
12.
Verify operation of heaters, if applicable.
13.
required.
7.

7.5
Switches (cont.)
1.
Air Switches (cont.)
1.
Low-Voltage (cont.)
14.
2.
1.

parts.
2.
Electrical Tests
1.
3.
Lubrication
Perform insulation-resistance tests on each pole, phase-to-phase and

phase-to-ground with switch closed and across each open pole for one
minute. Test voltage shall be in accordance with manufacturer's published
data or Table 10.1.
2.
Measure contact-resistance across each switchblade and fuse holder.
3.
Measure fuse resistance.
4.

5.
Perform ground-fault test in accordance with Section 7.14, if applicable.
Test Values
1.
2.

3.
from adjacent poles or similar switches by more than 25 percent of the
lowest value.
4.
Minimum insulation resistance shall be in accordance with manufacturer's

published data or Table 10.1.
5.
Investigate fuse-resistance values that deviate from each other by more

than 15 percent.
MTS-1997 39
7.

7.5
Switches (cont.)
1.
2.
Medium-Voltage, Metal-Enclosed
1.
40 MTS-1997

1.
2.
Verify appropriate anchorage and required area clearances.
3.
4.
Verify correct blade alignment, blade penetration, travel stops, and

mechanical operation.
5.
Verify that fuse sizes and types are in accordance with drawings and
short-circuit and coordination studies.
6.
Verify that expulsion-limiting devices are in place on all holders having

expulsion-type elements.
7.
Verify that each fuse holder has adequate mechanical support.
8.
1.

2.

3.
9.
Test all interlocking systems for correct operation and sequencing.
10.

11.
12.
Compare switchblade clearances with industry standards.
7.

7.5
Switches (cont.)
1.
2.
Medium-Voltage, Metal-Enclosed (cont.)
2.
3.
13.
Verify all indicating and control devices for correct operation.
14.
Verify operation of heaters, if applicable.
15.
required.
16.
Lubrication
1.

parts.
2.
Electrical Tests
1.
Perform insulation-resistance tests on each pole, phase-to-phase and

phase-to-ground with switch closed and across each open pole for one
minute. Test voltage shall be in accordance with manufacturer's published
data or Table 10.1.
2.
Perform an overpotential test on each pole with switch closed. Test each
pole-to-ground with all other poles grounded. Test voltage shall be in
accordance with manufacturer's published data or Table 10.2.
3.

4.
Measure contact resistance across each switchblade and fuse holder.
5.
Measure fuse resistance.
Test Values
1.
2.

MTS-1997 41
7.

7.5
Switches (cont.)
1.
2.
Medium-Voltage, Metal-Enclosed (cont.)
42 MTS-1997
3.
lowest value.
4.
5.
Insulation resistance shall be in accordance with Table 10.1.
6.
Investigate fuse resistance values that deviate from each other by more
than 15 percent.
7.

7.5
Switches (cont.)
1.
3.
High- and Medium-Voltage, Open
1.

1.
2.
3.
1.

2.

3.
4.
Perform mechanical operator tests in accordance with manufacturer's

published data, if applicable.
5.
Verify correct operation and adjustment of motor operator limit-switches

and mechanical interlocks, if applicable.
6.
Verify correct blade alignment, blade penetration, travel stops, arc

interrupter operation, and mechanical operation.
7.

8.
required.
9.
Lubrication
1.

parts.
2.
MTS-1997 43
7.

7.5
Switches (cont.)
1.
3.
High- and Medium-Voltage, Open (cont.)
2.
3.
* Optional
44 MTS-1997
Electrical Tests
1.

*2.
Perform insulation-resistance tests on each pole phase-to-ground with

switch closed for one minute. Test voltage should be in accordance with
3.
4.
Perform contact-resistance test across each switchblade and fuse holder.
Test Values
1.
2.

3.
lowest value.
4.
Insulation resistance values shall be in accordance with manufacturer's

data or Table 10.1.
5.
7.

7.5
Switches (cont.)
2.
Oil Switches: Medium-Voltage
1.

1.
2.
Inspect anchorage, alignment, and grounding.
3.

4.

5.
Verify correct blade alignment, blade penetration, travel stops, arc

interrupter operation, and mechanical operation.
6.

7.
Check each fuse holder for adequate support and contact.
8.
Verify that fuse sizes and types correspond to drawings.
9.
Test all electrical and mechanical interlock systems for correct operation
and sequencing.
10.
11.
1.

2.

3.
Verify that insulating oil level is correct.
MTS-1997 45
7.

7.5
Switches (cont.)
2.
Oil Switches: Medium-Voltage (cont.)
2.
12.
Inspect and/or replace gaskets as recommended by the manufacturer as

required.
13.
Lubrication
2.
required.
15.
Record as-found and as-left operation counter readings, if applicable.
Electrical Tests
1.
Perform a contact-resistance test.
2.

3.

*5.
46 MTS-1997

parts.
14.
4.
* Optional
1.
1.
Dielectric breakdown voltage: ASTM D877
2.
3.
Visual condition: ASTM D1524
Perform insulation-resistance tests pole-to-pole, pole-to-ground, and

across open poles at 2500 volts minimum.
Perform insulation resistance test on all control wiring at 1000 volts dc.
recommendations.
7.

7.5
Switches (cont.)
2.
Oil Switches: Medium-Voltage (cont.)
*6.
3.
Test Values
1.
2.

3.
lowest value.
4.
5.
Control wiring insulation resistance shall be a minimum of two megohms.
6.
* Optional
MTS-1997 47
7.

7.5
Switches (cont.)
3.
Vacuum Switches: Medium-Voltage
1.
48 MTS-1997

1.
2.
3.

4.

5.
Measure critical distances such as contact gap as recommended by

manufacturer.
6.
1.
Use of low-resistance ohmmeter. See Section 7.5.3.2.1 Electrical

Tests).
2.

3.
7.

8.
Check each fuse holder for adequate support and contact.
9.
10.
and sequencing.
11.
Verify oil level, if applicable.
7.

7.5
Switches (cont.)
3.
Vacuum Switches: Medium-Voltage (cont.)
12.
2.
Lubrication
1.

parts.
2.
13.
required.
14.
Record as-found and as-left operation counter readings, if applicable.
Electrical Tests
1.
Perform resistance measurements through all bus joints with a lowresistance ohmmeter, if applicable. See Section 7.5.3.1.7 (Visual and
Mechanical Inspection).
2.
3.
Verify open and close operation from control devices, if applicable.
4.

5.
Perform vacuum bottle integrity (overpotential) test across each vacuum

bottle with the switch in the open position in strict accordance with
manufacturer's published data. Do not exceed maximum voltage
stipulated for this test. Provide adequate barriers and protection against
x-radiation during this test. Do not perform this test unless the contact
displacement of each interrupter is within manufacturer's tolerance. (Be
aware that some dc high-potential test sets are half-wave rectified and
may produce peak voltages in excess of the switch manufacturer's
recommended maximum.)
MTS-1997 49
7.

7.5
Switches (cont.)
3.
Vacuum Switches: Medium-Voltage (cont.)
6.
3.
* Optional
50 MTS-1997
Remove a sample of insulating liquid, if applicable, in accordance with

ASTM D-923. Sample shall be tested in accordance with the referenced
standard.
1.
Dielectric breakdown voltage: ASTM D-877
2.
Color: ASTM D-1500
3.
Visual condition: ASTM D-1524
*7.
Perform insulation-resistance test on all control wiring at 1000 volts dc.

recommendations.
*8.
Perform an overpotential test in accordance with manufacturer's published

data.
Test Values
1.
2.

3.
lowest value.
4.
Contact displacement shall be in accordance with factory recorded data

marked on the nameplate of each vacuum switch or bottle.
5.
The vacuum bottles shall withstand the overpotential voltage applied.
6.
7.
8.
7.

4.
SF6 Switches: Medium-Voltage - Reserved
5.
Cutouts - Reserved
MTS-1997 51
7.

7.6
Circuit Breakers
1.
Low-Voltage
1.
Insulated Case/Molded Case
1.

1.
Inspect circuit breaker for correct mounting.
2.
Operate circuit breaker to insure smooth operation.
3.
Inspect case for cracks or other defects.
4.
5.
2.
* Optional
52 MTS-1997
1.

2.

3.
Inspect mechanism contacts and arc chutes in unsealed units.
Electrical Tests
1.
2.
Perform an insulation-resistance test at 1000 volts dc from pole-to-pole

and from each pole-to-ground with breaker closed and across open
contacts of each phase.
3.

*4.
Perform insulation resistance test at 1000 volts dc on all control wiring.

recommendations.
7.

7.6
Circuit Breakers (cont.)

1.
Low-Voltage (cont.)
1.
Insulated Case/Molded Case (cont.)
5.
Perform long-time delay time-current characteristic tests by passing 300

percent rated current through each pole separately unless series testing is
required to defeat ground fault functions.
6.
Determine short-time pickup and delay by primary current injection.
7.
Determine ground-fault pickup and time delay by primary current injection.
8.
Determine instantaneous pickup current by primary injection using run-up

or pulse method.
9.
Verify correct operation of any auxiliary features such as trip and pickup
indicators, zone interlocking, electrical close and trip operation, trip-free,
and antipump function.
*10.
3.
Verify the calibration of all functions of the trip unit by means of secondary
injection.
Test Values
1.
2.

3.
from adjacent poles or similar breakers by more than 25 percent of the
lowest value.
4.
Circuit breaker insulation resistance shall be in accordance with Table

10.1.
5.
* Optional
MTS-1997 53
7.

7.6

1.
Low-Voltage (cont.)
1.
Insulated Case/Molded Case (cont.)
54 MTS-1997
6.
Trip characteristic of breakers shall fall within manufacturer's published

time-current characteristic tolerance band, including adjustment factors.
7.
For molded-case circuit breakers all trip times shall fall within Table 10.7.
Circuit breakers exceeding specified trip time at 300 percent of pickup
shall be tagged defective.
8.
For molded-case circuit breakers instantaneous pickup values shall be

within values shown in Table 10.8.
7.

7.6

1.
Low-Voltage (cont.)
2.
Power
1.

1.
2.
Inspect anchorage, alignment, and grounding. Inspect arc chutes. Inspect

moving and stationary contacts for condition, wear, and alignment.
3.
Verify that all maintenance devices are available for servicing and
operating the breaker.
4.
Verify that primary and secondary contact wipe and other dimensions vital
to satisfactory operation of the breaker are correct.
5.
Perform all mechanical operator and contact alignment tests on both the
breaker and its operating mechanism.
6.
1.

2.

3.
7.
Verify cell fit and element alignment.
8.
Verify racking mechanism.
9.
required.
MTS-1997 55
7.

7.6

1.
Low-Voltage (cont.)
2.
Power (cont.)
10.
2.
56 MTS-1997
1.

parts.
2.
Electrical Tests
1.
2.
Perform an insulation-resistance test at 1000 volts dc from pole-to-pole

and from each pole-to-ground with breaker closed and across open
contacts of each phase.
3.
*4.
* Optional
Lubrication
1.

2.

3.
Perform an insulation-resistance test at 1000 volts dc on all control wiring.

recommendations.
5.
Make adjustments for the final settings in accordance with the

coordination study supplied by owner.
6.
Determine minimum pickup current by primary current injection.
7.
Determine long-time delay by primary current injection.
7.

7.6

1.
Low-Voltage (cont.)
2.
Power (cont.)
8.
Determine short-time pickup and delay by primary current injection.
9.
Determine ground-fault pickup and delay by primary current injection.
10.
3.
Determine instantaneous pickup value by primary current injection.
*11.
Verify the calibration of all functions of the trip unit by means of secondary
injection.
12.
Activate auxiliary protective devices, such as ground-fault or undervoltage

relays, to insure operation of shunt trip devices. Check the operation of
electrically-operated breakers in their cubicles.
13.
Verify correct operation of any auxiliary features such as trip and pickup
indicators, zone interlocking, electrical close and trip operation, trip-free,
and antipump function.
14.
Verify operation of charging mechanism.
Test Values
1.
2.

3.
lowest value.
4.

10.1.
5.
6.
Trip characteristics of breakers shall fall within manufacturer's published

time-current tolerance bands.
* Optional
MTS-1997 57
7.

7.6

2.
Medium-Voltage
1.
Air
1.

1.
2.
Inspect anchorage, alignment, and grounding. Inspect arc chutes. Inspect

moving and stationary contacts for condition, wear, and alignment.
3.
Verify that all maintenance devices are available for servicing and
operating the breaker.
4.
Verify that primary and secondary contact wipe and other dimensions vital
to satisfactory operation of the breaker are correct.
5.
Perform all mechanical operator and contact alignment tests on both the
breaker and its operating mechanism.
6.
2.

3.
7.
Verify cell fit and element alignment.
8.
Verify racking mechanism.
9.
Inspect puffer operation.
10.
58 MTS-1997
1.
required.
7.

7.6

2.
Medium-Voltage (cont.)
1.
Air (cont.)
11.
12.
2.
Lubrication
1.

parts.
2.
Record as-found and as-left operation-counter readings.
Electrical Tests
1.
2.
Measure insulation resistance pole-to-pole, pole-to-ground, and across

open poles. Use a minimum test voltage of 2500 volts.
3.

low-resistance ohmmeter, if applicable. See Section 7.6.2.1.1.6 (Visual
and Mechanical Inspection).
*4.
Perform insulation-resistance test at 1000 volts dc on all control wiring.

recommendations.
5.
With breaker in the test position, make the following tests:

1.
Trip and close breaker with the control switch.
2.
Trip breaker by operating each of its protective relays.
3.
Verify trip-free and antipump function.
*4.
Perform minimum pickup voltage tests on trip and close coils.
*6.
Perform dissipation-factor/power-factor test with breaker in both the
*7.

data.
8.
Measure blow-out coil circuit resistance.
* Optional
MTS-1997 59
7.

7.6

2.
1.
Air (cont.)
3.
60 MTS-1997
Test Values
1.
2.

3.
lowest value.
4.

10.1.
5.
6.
Dissipation-factor/power-factor test results shall be compared with

previous tests of similar breakers or manufacturer's published data.
7.
8.
Minimum pickup for trip and close coils shall conform to manufacturer's
published data.
7.

7.6

2.
2.
Oil
1.

1.
2.
Verify correct oil level in all tanks and bushings.
3.
4.
Verify that breather vents are clear.
5.
Perform all mechanical operation tests on the operating mechanism in

accordance with manufacturer's published data.
6.
If performing internal inspection:
7.
1.
Remove oil. Lower tanks or remove manhole covers as necessary.

Inspect bottom of tank for broken parts and debris and clean
carbon residue from tank.
2.
Inspect lift rod and toggle assemblies, contacts, interrupters,

bumpers, dashpots, bushing current transformers, tank liners, and
gaskets.
3.
Slow-close breaker and check for binding, friction, contact

alignment, penetration, and overtravel. Check that all phases make
contact simultaneously.
4.
Refill tank(s) with filtered oil to correct levels.
1.

2.

3.
MTS-1997 61
7.

7.6

2.
2.
Oil (cont.)
8.
*9.
Perform circuit breaker time-travel analysis.
10.
required.
11.
Lubrication
12.
2.
Test alarms and lockouts for pneumatic and/or hydraulic operators as

recommended by the manufacturer.
1.

parts.
2.
Record as-found and as-left operation counter readings.
Electrical Tests
1.
2.

1.
2.
*3.
Power factor: ASTM D924
*4.
Interfacial tension: ANSI/ASTM D971 or ANSI/ASTM D-2285
5.
* Optional
62 MTS-1997
3.
Trip circuit breaker by operation of each protective device.
4.

7.

7.6

2.
2.
Oil (cont.)
3.
5.

*6.

recommendations.
7.
Perform dissipation factor/power factor tests on each pole with breaker

open and each phase with breaker closed. Determine tank loss index.
8.
Perform dissipation-factor/power-factor tests on each bushing. Use

conductive straps and hot collar procedures if bushings are not equipped
with a power-factor tap.
9.
Verify trip, close, trip-free, and antipump functions.
*10.
*11.

data.
Test Values
1.
2.

3.
lowest value.
4.
Compare circuit breaker travel and velocity values to manufacturer's

acceptable limits.
* Optional
MTS-1997 63
7.

7.6

2.
2.
Oil (cont.)
64 MTS-1997
5.
Insulating-liquid test results shall be in accordance with Table 10.4.
6.

10.1.
7.
8.
Dissipation-factor/power-factor test results and tank loss index shall be

compared to manufacturer's published data. In the absence of
manufacturer's published data, the comparison shall be made to similar
breakers.
9.
Dissipation-factor/power-factor and capacitance test results shall be within

ten percent of nameplate rating for bushings.
10.
11.
published data.
7.

7.6

2.
3.
Vacuum
1.

1.
2.
3.
Perform all mechanical operational tests on both the circuit breaker and its
operating mechanism.
4.
Measure critical distances such as contact gap as recommended by

manufacturer.
5.
1.

2.

3.
6.
required.
7.
Lubrication
8.
1.

parts.
2.
MTS-1997 65
7.

7.6

2.
3.
Vacuum (cont.)
2.
Electrical Tests
1.
*2.
Perform breaker operating time and velocity analysis.
*3.
4.
5.
6.

7.

8.
Perform vacuum bottle integrity (overpotential) test across each vacuum

bottle with the breaker in the open position in strict accordance with
manufacturer's published data. Do not exceed maximum voltage
stipulated for this test. Provide adequate barriers and protection against
x-radiation during this test. Do not perform this test unless the contact
displacement of each interrupter is within manufacturer's tolerance. (Be
aware that some dc high-potential test sets are half-wave rectified and
may produce peak voltages in excess of the breaker manufacturer's
recommended maximum.)
*9.
* Optional
66 MTS-1997

recommendations.
*10.
Perform dissipation-factor/power-factor tests on each pole with the

breaker open and each phase with the breaker closed.
*11.
Perform dissipation-factor/power-factor tests on each bushing. Use

conductive straps and hot collar procedures if bushings are not equipped
with a power factor tap.
*12.

data.
7.

7.6

2.
3.
Vacuum (cont.)
3.
Test Values
1.
2.

3.
lowest value.
4.

10.1.
5.
Contact displacement shall be in accordance with factory recorded data

marked on the nameplate of each vacuum breaker or bottle.
6.
The interrupter shall withstand the overpotential voltage applied.
7.
Compare circuit breaker timing values to manufacturer's published data.
8.
9.
Dissipation-factor/power-factor test results shall be compared to

manufacturer's published data. In the absence of manufacturer's
published data the comparison shall be made to similar breakers.
10.

11.
MTS-1997 67
7.

7.6

2.
4.
SF6
1.

1.
2.
Inspect anchorage and grounding.
3.
Inspect and verify adjustments of mechanism in accordance with

4.
Inspect and service air compressor in accordance with manufacturer's

published data.
5.
Inspect and service hydraulic system in accordance with manufacturer's

published data.
6.
Test for gas leaks in accordance with manufacturer's published data.
7.
Verify correct operation of all air and SF6 gas pressure alarms and
cutouts.
8.
Slow close/open breaker and check for binding.
9.
Perform time-travel analysis.
10.
11.
68 MTS-1997
1.

2.

3.
required.
7.

7.6

2.
4.
SF6 (cont.)
12.
13.
2.
Lubrication
1.

parts.
2.
Record as-found and as-left counter operations.
Electrical Tests
1.
2.

3.

*4.

recommendations.
*5.
Remove a sample of SF6 gas and test in accordance with Table 10.13.
*6.
Perform dissipation-factor/power-factor tests on breaker and bushings.
*7.
Perform overpotential test in accordance with manufacturer's published

data.
*8.
Perform minimum pick-up voltage test on trip and close coils.
9.
10.

* Optional
MTS-1997 69
7.

7.6

2.
4.
SF6 (cont.)
3.
70 MTS-1997
Test Values
1.
2.

3.
lowest value.
4.
Compare time-travel data with manufacturer's published data.
5.
6.

10.1.
7.

published data, the comparison shall be made to similar breakers.
8.

9.
SF6 gas will have values in accordance with Table 10.13
10.
11.
published data.
7.

7.6

3.
High-Voltage
1.
Oil
1.

1.
2.
Verify correct oil level in all tanks and bushings.
3.
4.
Verify that breather vents are clear.
5.
Perform all mechanical operation tests on the operating mechanism in

6.

1.
Remove oil. Lower tanks or remove manhole covers as necessary.

Inspect bottom of tank for broken parts and debris and clean
carbon residue from tank.
2.
Inspect lift rod and toggle assemblies, contacts, interrupters,

bumpers, dashpots, bushing current transformers, tank liners, and
gaskets.
3.
Slow-close breaker and check for binding, friction, contact

alignment, penetration, and overtravel. Check that all phases make
contact simultaneously.
4.
Refill tank(s) with filtered oil to correct levels.
7.
Inspect and service operating mechanism, hydraulic system, and/or air

compressor in accordance with manufacturer's published data.
8.
1.

2.
Verify tightness of accessible bolted electrical connections

bycalibrated torque-wrench method in accordance with
3.
MTS-1997 71
7.

7.6

3.
1.
Oil (cont.)
9.
10.
Perform circuit breaker time-travel analysis.
11.
required.
12.
Lubrication
13.
2.
Test alarms and lockouts for pneumatic and/or hydraulic operators as

recommended by the manufacturer.
1.

parts.
2.
Electrical Tests
1.
2.

1.
2.
*3.
*4.
Interfacial tension: ANSI/ASTM D971 or ANSI/ASTM D2285
5.
* Optional
72 MTS-1997
3.
4.
7.

7.6

3.
1.
Oil (cont.)
5.
3.

*6.

across open poles at 15,000 volts minimum.
*7.

recommendations.
8.
Perform power-factor tests on each pole with breaker open and each
phase with breaker closed. Determine tank loss index.
9.
Perform power-factor tests on each bushing. Use conductive straps and

hot collar procedures if bushings are not equipped with a power-factor tap.
*10.
*11.

data.
Test Values
1.
2.

3.
lowest value.
4.
Compare circuit breaker travel and velocity values to manufacturer's

published data and previous test data.
* Optional
MTS-1997 73
7.

7.6

3.
1.
Oil (cont.)
74 MTS-1997
5.
Insulating liquid test results shall be in accordance with Table 10.4.
6.

10.1.
7.
8.
Dissipation-factor/power-factor test results and tank loss index shall be

compared to manufacturer's published data. In the absence of
breakers.
9.

10.
11.
published data.
7.

7.6

3.
High Voltage (cont.)
2.
SF6
1.

1.
2.
Inspect anchorage alignment and grounding.
3.
Inspect and service operating mechanism and SF6 gas insulated system
in accordance with manufacturer's published data.
4.
Test for gas leaks in accordance with manufacturer's published data.
5.
Verify correct operation of all air and SF6 gas pressure alarms and
cutouts.
6.
Slow close/open breaker and check for binding.
7.
Perform time-travel analysis.
8.
9.
10.
11.
1.

2.

3.
required.
Lubrication
1.

parts.
2.
Record as-found and as-left counter operations.
MTS-1997 75
7.

7.6

3.
2.
SF6 (cont.)
2.
Electrical Tests
1.
2.

3.

*4.

recommendations.
*5.
Remove a sample of SF6 gas and test in accordance with Table 10.13.
*6.
Perform dissipation-factor/power-factor tests on breaker and bushings.
*7.
Perform overpotential test in accordance with manufacturer's published

data.
*8.
Perform minimum pick-up voltage test on trip and close coils.
9.
10.
3.
* Optional
76 MTS-1997

Test Values
1.
2.

3.
lowest value.
7.

7.6

3.
2.
SF6 (cont.)
4.
4.
Compare time-travel data with manufacturer's published data.
5.
6.

10.1.
7.

published data, the comparison shall be made to similar breakers.
8.

9.
SF6 gas will have values in accordance with Table 10.13.
10.
11.
published data.
Extra-High Voltage - Reserved
MTS-1997 77
7.

7.7
Circuit Switchers
1.

1.
2.
Lubrication
1.

parts.
2.
3.
4.
Perform all mechanical operational tests on both the circuit switcher and
its operating mechanism.
5.
1.
Use of low-resistance ohmmeter. See Section 7.7.2.1 (Electrical
Tests).
2.
calibrated torque-wrench method in accordance with manufacturer's
published data or Table 10.12.
3.
2.
6.
Verify correct operation of SF6 interrupters.
7.
Verify correct SF6 pressure.
8.
Verify correct operation of isolating switch.
9.
Electrical Tests
1.
78 MTS-1997
Perform resistance measurements through all connections with a lowresistance ohmmeter, if applicable, in accordance with Section 7.7.1.5
(Visual and Mechanical Inspection).
7.

7.7
Circuit Switchers (cont.)

2.
*3.
4.
Trip circuit switcher by operation of each protective device.
5.
Verify correct operation of electrical shunt trip of interrupters.
*6.

*7.

recommendations.
8.
3.
Perform contact-resistance test of interrupters and isolating switches.

data.
Test Values
1.
2.

3.
from adjacent poles or similar switchers by more than 25 percent of the
lowest value.
4.
published data.
5.
Circuit switcher insulation resistance shall be in accordance with Table

10.1.
6.
7.
* Optional
MTS-1997 79
7.

7.8
Network Protectors, 600 Volt Class

1.
80 MTS-1997

1.
Open the protector and rack it out of the enclosure. Note that the network
bus and transformer generally will be energized. Exercise extreme
caution. Observe clearances and check for smoothness of operation when
racking.
2.
3.
Inspect the enclosure door gasket and sight glass for damage.
4.
Inspect the interior of the enclosure for debris or damaged components.

Inspect insulating components, current carrying parts, and secondary
disconnecting devices. Exercise extreme caution when working around
the network bus conductors.
5.
Check for missing parts on the protector. Check tightness of electrical and
mechanical connections. Tighten as necessary according to
6.
Inspect insulating barriers for damage and correct mounting.
7.
Inspect network protector fuse covers, fuses, and blown fuse indicators for
damage.
8.
Inspect closing motor brushes and commutator surface for wear or

damage. Replace brushes or disassemble motor for cleaning as
necessary. Inspect and clean motor brake mechanism, as applicable.
9.
Remove and inspect arc chutes for damage.
10.
Inspect main and arcing contacts. Clean surfaces and align contacts as
necessary.
11.
Verify sequence of main and arcing contacts by slow-closing the protector.

Adjust as necessary according to manufacturer's published data.
12.
Manually open and close the protector and verify that the mechanism
latches correctly in each position. Verify correct operation of the position
indicator.
7.

7.8
Network Protectors, 600 Volt Class (cont.)
2.
13.
Verify electrical connections to network and auxiliary relays. Clean relay

contacts if necessary. Inspect electromechanical relays for freedom of
movement of internal parts.
14.
Verify electrical connections to auxiliary switches, secondary disconnects,

current transformers, voltage transformers, control power transformers,
closing motors, contactors, trip coils, loading resistors, and any other
auxiliary devices.
15.
required.
16.
Lubrication
1.

parts.
2.
17.
Record the as-found and as-left operations counter readings.
18.
Perform a leak test on submersible enclosure in accordance with

Electrical Tests
1.
Perform insulation-resistance tests at 1000 volts dc for one minute across

the contacts of each pole with the protector open and from pole-to-pole
and each pole-to-ground with the protector closed.
*2.
Perform insulation-resistance tests at 1000 volts dc on all control wiring

and electromechanical components. For units with solid-state
components, follow manufacturer's recommendations.
*3.
Verify current transformer ratios in accordance with Section 7.10.
4.
*5.
6.

Measure the resistance of each protector power fuse.
Measure minimum pickup voltage of motor control relay.
* Optional
MTS-1997 81
7.

7.8

*7.
8.
Measure minimum pickup voltage of the trip actuator. Verify that the
actuator resets correctly.
9.
Calibrate the network protector relays in accordance with Section 7.9.
10.
3.
* Optional
82 MTS-1997
Verify that the motor can charge the closing mechanism at the minimum
voltage specified by the manufacturer.
Perform operational tests.

1.
Verify correct operation of all mechanical and electrical interlocks.
2.
Verify trip-free operation.
3.
Verify correct operation of the auto-open-close control handle.
4.
Verify the protector will close with voltage on the transformer side
only.
5.
Verify the protector will open when the source feeder breaker is
opened.
Test Values
1.
2.

3.
from adjacent poles or similar protectors by more than 25 percent of the
lowest value.
4.
Insulation resistance of the protector components shall be in accordance

with Table 10.1.
5.
6.
Resistance of power fuses shall be evaluated on a comparative basis.
7.

7.8

7.
Minimum voltage to operate the trip actuator shall not exceed 7.5 percent
of rated control circuit voltage.
8.
Minimum acceptable motor closing voltage shall not exceed 73 percent of

rated control circuit voltage.
9.
Network protector should automatically close upon closing the feeder

breaker with normal load demand and automatically trip when source
feeder breaker is opened.
MTS-1997 83
7.

7.9
Protective Relays
1.
2.
3.

1.
Inspect relays and cases for physical damage.
2.
Tighten case connections. Inspect cover for correct gasket seal. Clean
cover glass. Inspect shorting hardware, connection paddles, and/or knife
switches. Remove any foreign material from the case. Verify target reset.
3.
Inspect relay for foreign material, particularly in disc slots of the damping
and electromagnets. Verify disk clearance. Verify contact clearance and
spring bias. Inspect spiral spring convolutions. Inspect disk and contacts
for freedom of movement and correct travel. Verify tightness of mounting
hardware and connections. Burnish contacts. Inspect bearings and/or
pivots.
4.
Verify that all settings are in accordance with coordination study or setting
sheet supplied by owner.
Electrical Tests
1.
Perform insulation-resistance test on each circuit-to-frame. Determine

from the manufacturer's published data the allowable procedures for this
test for solid-state and microprocessor-based relays.
2.
Inspect targets and indicators.

Determine pickup and dropout of electromechanical targets.
2.
Verify operation of all light-emitting diode indicators.
3.
Set contrast for liquid-crystal display readouts.
Functional Operation
1.
84 MTS-1997
1.
2/62 Timing Relay

1.
Determine time delay.
2.
Verify operation of instantaneous contacts.
7.

7.9
Protective Relays (cont.)

2.
21 Distance Relay
1.
Determine maximum reach.
2.
Determine maximum torque angle.
3.
Determine offset.
*4.
3.
4.
5.
Plot impedance circle.
24 Volts/Hertz Relay
1.
Determine pickup frequency at rated voltage.
2.
Determine pickup frequency at a second voltage level.
3.
25 Sync Check Relay

1.
Determine closing zone at rated voltage.
2.
Determine maximum voltage differential that permits closing at zero

degrees.
3.
Determine live line, live bus, dead line, and dead bus set points.
4.
5.
Verify dead bus/live line, dead line/live bus and dead bus/dead line
control functions.
27 Undervoltage Relay
1.
Determine dropout voltage.
2.
3.
Determine the time delay at a second point on the timing curve for
inverse time relays.
* Optional
MTS-1997 85
7.

7.9

6.
32 Directional Power Relay

1.
Determine minimum pickup at maximum torque angle.
2.
Determine closing zone.
3.
4.
5.
Verify the time delay at a second point on the timing curve for
inverse time relays.
*6.
7.
40 Loss of Field (Impedance) Relay

1.
Determine maximum reach.
2.
3.
Determine offset.
*4.
8.
9.
* Optional
86 MTS-1997
Plot the operating characteristic.
Plot impedance circle.
46 Current Balance Relay

1.
Determine pickup of each unit.
2.
Determine percent slope.
3.
46N Negative Sequence Current Relay

1.
Determine negative sequence alarm level and trip.
2.
Determine negative sequence minimum trip level.
3.
Determine maximum time delay.
4.
Verify two points on the (I2)2t curve.
7.

7.9

10.
11.
47 Phase Sequence or Phase Balance Voltage Relay

1.
Determine positive sequence voltage to close the normally open

contact.
2.
Determine positive sequence voltage to open the normally closed

contact (undervoltage trip).
3.
Verify negative sequence trip.
4.
Determine time delay to close the normally open contact with

sudden application of 120 percent of pickup.
5.
Determine time delay to close the normally closed contact upon

removal of voltage when previously set to rated system voltage.
49R Thermal Replica Relay

1.
Determine time delay at 300 percent of setting.
2.
Determine a second point on the operating curve.
*3.
12.
13.
49T Temperature (RTD) Relay

1.
Determine trip resistance.
2.
Determine reset resistance.
50 Instantaneous Overcurrent Relay

1.
Determine pickup.
2.
Determine dropout.
*3.
14.
15.
Determine pickup.
51 Time Overcurrent
1.
Determine minimum pickup.
2.
Determine time delays at two points on the time current curve.
55 Power Factor Relay

1.
Determine tripping angle.
2.
* Optional
MTS-1997 87
7.

7.9

16.
17.
59 Overvoltage Relay
1.
Determine overvoltage pickup.
2.
Determine time delay to close the contact with sudden application

of 120 percent of pickup.
60 Voltage Balance Relay

1.
*2.
18.
19.
* Optional
88 MTS-1997
Plot the operating curve for the relay.
63 Transformer Sudden Pressure Relay

1.
Determine rate-of-rise or the pickup level of suddenly applied

pressure in accordance with manufacturer's specifications.
2.
Verify operation of the 63 FPX seal-in circuit.
3.
Verify trip circuit to remote breaker.
64 Ground Detector Relay

1.
20.
Determine voltage difference to close the contacts with one source

at rated voltage.
Determine maximum impedance to ground causing relay pickup.
67 Directional Overcurrent Relay

1.
Determine directional unit minimum pickup at maximum torque

angle.
2.
Determine closing zone.
*3.
*4.
Plot operating characteristics.
5.
Determine overcurrent unit pickup.
6.
Determine overcurrent unit time delay at two points on the time

current curve.
7.

7.9

21.
79 Reclosing Relay
1.
Determine time delay for each programmed reclosing interval.
2.
Verify lockout for unsuccessful reclosing.
3.
Determine reset time.
*4.
5.
22.
23.
24.
Determine close pulse duration.

Verify instantaneous overcurrent lockout.
81 Frequency Relay
1.
Verify frequency set points.
2.
3.
Determine undervoltage cutoff.
85 Pilot Wire Monitor

1.
Determine overcurrent pickup.
2.
Determine undercurrent pickup.
3.
Determine pilot wire ground pickup level.
87 Differential
1.
Determine operating unit pickup.
2.
Determine the operation of each restraint unit.
3.
Determine slope.
4.
Determine harmonic restraint.
5.
Determine instantaneous pickup.
*6.
Plot operating characteristics for each restraint.
* Optional
MTS-1997 89
7.

7.9

4.
Control Verification
1.
5.
90 MTS-1997
Verify that each of the relay contacts performs its intended function in the
control scheme including breaker trip tests, close inhibit tests, 86 lockout
tests, and alarm functions.
Test Values
1.
When not otherwise specified, use manufacturer's recommended

tolerances.
2.
When critical test points are specified, the relay should be calibrated to
those points even though other test points may be out of tolerance.
7.

7.10 Instrument Transformers
1.
2.

1.
2.
1.

7.10.2.1 and 7.10.3.1 (Electrical Tests).
2.

3.
Verify that all required grounding and shorting connections provide

contact.
4.
Verify correct operation of transformer withdrawal mechanism and

grounding operation.
5.
Verify correct primary and secondary fuse sizes for voltage (potential)
transformers.
6.
required.
Electrical Tests - Current Transformers

1.

7.10.1.2 (Visual and Mechanical Inspection).
2.
Perform insulation-resistance test of the current transformer and wiring-toground at 1000 volts dc. For units with solid-state components, follow
manufacturer's recommendations.
3.
Perform a polarity test of each current transformer.
MTS-1997 91
7.

7.10 Instrument Transformers (cont.)
3.
* Optional
92 MTS-1997
4.
Perform a ratio-verification test using the voltage or current method in

accordance with ANSI/IEEE C57.13.1.
5.
Perform an excitation test on transformers used for relaying applications

in accordance with ANSI/IEEE C57.13.1.
6.
Measure current circuit burdens at transformer terminals and determine

the total burden.
7.
When applicable, perform insulation-resistance and dielectric withstand

tests on the primary winding with secondary grounded. Test voltages shall
be in accordance with Tables 10.1 and 10.9 respectively.
Electrical Tests - Voltage Transformers

1.

2.
Perform insulation-resistance tests winding-to-winding and each windingto-ground. Test voltages shall be applied for one minute in accordance
with Table 10.1. Do not perform this test with solid-state devices
connected.
3.
Perform a polarity test on each transformer to verify the polarity marks or

H1-X1 relationship as applicable.
4.
Perform a turns ratio test on all tap positions, if applicable.
5.
Measure potential circuit burdens at transformer terminals and determine

the total burden.
*6.
Perform a dielectric withstand test on the primary windings with the

secondary windings connected to ground. The dielectric voltage shall be
in accordance with Table 10.9. The test voltage shall be applied for one
minute.
7.

7.10 Instrument Transformers (cont.)
4.
Test Values
1.
2.

3.
4.
Insulation-resistance measurement on any instrument transformer shall

be not less than that shown in Table 10.1.
5.
Polarity results shall agree with transformer markings.
6.
Compare measured burdens to calculated burdens supplied by owner.
7.
Ratio accuracies shall be within 0.5 percent of nameplate or

8.
MTS-1997 93
7.

7.11 Metering
1.
2.

1.
2.
Verify tightness of electrical connections.
3.
Inspect cover gasket, cover glass, condition of spiral spring, disc

clearance, contacts, and case-shorting contacts, as applicable.
4.
Verify freedom of movement, end play, and alignment of rotating disk(s).
5.
required.
Electrical Tests
1.
Check calibration of meters at all cardinal points.
2.
Calibrate meters in accordance to manufacturer's published data.
*3.
* Optional
94 MTS-1997
Verify all instrument multipliers.
7.

7.12 Regulating Apparatus
1.
Voltage
1.
Step Voltage Regulators
1.

1.
Record position indicator as-found, maximum, and minimum values.
2.
3.
Verify auxiliary device operation.
4.
1.

2.

3.
5.
Verify motor and drive train for correct operation and automatic motor cutoff at maximum lower and maximum raise.
6.
Verify correct liquid level in all tanks and bushings.
7.

the manufacturer.
8.
Verify operation of heaters.
9.
Verify equipment grounding.
MTS-1997 95
7.

7.12 Regulating Apparatus (cont.)
1.
Voltage (cont.)
1.
Step Voltage Regulators (cont.)
10.
1.
Remove oil.
2.
Clean carbon residue and debris from compartment.
3.
Inspect contacts for wear and alignment.
4.
Inspect all electrical and mechanical connections for tightness

using calibrated torque wrench method in accordance with
5.
Inspect tap changer compartment terminal board, contact support

boards, and insulating operating components for evidence of
moisture, cracks, excessive wear, breakage, and/or signs of
electrical tracking.
6.
Electrically operate tap change through full range of taps.
7.
Replace gaskets and seal compartment.
8.
Fill with filtered oil.
11.
required.
12.
Lubrication
13.
96 MTS-1997
If performing internal inspection on station regulator:
1.

parts.
2.
7.

1.
Voltage (cont.)
1.
2.
Electrical Tests
1.

2.
Perform insulation-resistance tests on each winding-to-ground in any offneutral position with the test voltage in accordance with Table 10.5. Test
duration shall be for ten minutes. Calculate polarization index.
3.
Perform insulation power-factor/dissipation-factor tests on windings and

correct to 20C in accordance with test equipment manufacturer's
published data.
4.
Perform power-factor/dissipation-factor tests (or hot collar watts-loss test)

on bushings and correct to 20C in accordance with test equipment
5.
Measure winding-resistance of source windings in the neutral position.

Measure the resistance of each load winding at all tap positions.
6.
Perform special tests and adjustments as recommended by manufacturer.
*7.
If the regulator has a separate tap-changer compartment, measure the

percentage of oxygen in the nitrogen gas blanket in the main tank.
8.
Perform turns ratio test on each voltage step position. Verify that the
indicator correctly identifies all tap positions.
9.
Verify accurate operation of voltage range limiter.
10.
*11.
Verify functioning and accuracy of bandwidth, time delay, voltage and linedrop compensation adjustments.
If regulator has a separate tap-changer compartment, sample insulating
liquid in the main tank in accordance with ASTM D3613 and perform
dissolved-gas analysis in accordance with ANSI/IEEE C57.104 or ASTM
D3612.
* Optional
MTS-1997 97
7.

1.
Voltage (cont.)
1.
12.
13.
*14.
Remove a sample of insulating liquid from the main tank or common tank
in accordance with ASTM D923. Sample shall be tested in accordance
with the referenced standard.
1.
2.
3.
4.
Interfacial tension: ANSI/ASTM D971 or ASTM D2285
5.
6.
*7.

Required when the regulator voltage is 46 kV or higher.
*8.
PPM water: ASTM D1533

Required when the regulator voltage is 25 kV or higher and on all
silicone-filled units.
Remove a sample of insulating liquid from the tap-changer tank in

accordance with ASTM D923. Sample shall be tested in accordance with
the referenced standard.
1.
2.
3.
Remove a sample of insulating liquid from the tap changer compartment

or common tank in accordance with ASTM D3613 and perform dissolved
gas analysis (DGA) in accordance with ANSI/IEEE C57.104 or ASTM
D3612.
NOTE: Although there is no ANSI/IEEE standard for evaluating dissolved
gas in regulator and load tap changer interrupter compartments, studies
have indicated there is value in comparing dissolved gases to the oil from
similarly designed regulators and load-tap changers.
* Optional
98 MTS-1997
7.

1.
Voltage (cont.)
1.
3.
Test Values
1.
2.

3.
4.
Insulation-resistance values at one minute should not be less than values

recommended in Table 10.5. Resistance values shall be temperature
5.
6.
Maximum power-factor of liquid-filled regulators corrected to 20C shall be

in accordance with manufacturer's published data. Representative values
are indicated in Table 10.3.
7.
Bushing power factors and capacitances should not vary by more than ten
percent of the nameplate values. Investigate any hot collar watts-loss
results that exceed the test equipment manufacturer's published data.
8.
Consult manufacturer if winding-resistance test results vary more than

one percent from test results of adjacent windings.
9.
Turns-ratio test results shall maintain a normal deviation between each

voltage step and shall not deviate more than one-half percent from the
calculated voltage ratio.
10.
11.
12.
Compare results of dissolved gas analysis to previous test results.
MTS-1997 99
7.

1.
Voltage (cont.)
2.
Induction Regulators
1.
100 MTS-1997

1.
2.
3.
Verify correct auxiliary device operation.
4.
1.

2.

3.
5.
Check motor and drive train for correct operation and automatic motor cutoff at maximum lower and maximum raise.
6.
Verify appropriate liquid level in all tanks and bushings, if applicable.
7.

the manufacturer.
8.
Verify heater operations.
9.
10.
required.
11.
Lubrication
1.
Verify appropriate contact lubricant on moving current-carrying parts.
2.
7.

1.
Voltage (cont.)
2.
Induction Regulators (cont.)
2.
Electrical Tests
1.

2.
Perform insulation-resistance tests winding-to-winding and winding-toground in accordance with Table 10.5. Test duration shall be ten minutes.
3.
Perform winding insulation power-factor/dissipation-factor tests on

windings and correct to 20C in accordance with test equipment
4.
Perform power-factor/dissipation-factor or hot collar watts-loss tests on

bushings and correct to 20C in accordance with test equipment
5.
Verify voltage regulation.
6.
Verify that the indicator correctly identifies neutral position.
7.
Perform winding resistance tests on each winding.
8.
Sample insulating liquid, if applicable, in accordance with ASTM D923.

1.
2.
*3.
4.
Interfacial tension: ANSI/ASTM D971 or ASTM D2285
5.
6.
*7.

*8.
Water content: ASTM D1533

* Optional
MTS-1997 101
7.

1.
Voltage (cont.)
2.
3.
* Optional
102 MTS-1997
*9.

ASTM D3613 and perform dissolved gas (DGA) analysis in accordance
with ASTM D3612 or ANSI.IEEE C57.104.
*10.
Measure the percent of oxygen in the nitrogen gas blanket, if applicable.
Test Values
1.
2.

3.
4.
Insulation-resistance value at one minute shall not be less than values

5.
6.
Maximum power factor of liquid-filled regulators corrected to 20C shall be

in accordance with manufacturer's specifications. Representative values
are indicated in Table 10.3.
7.
Bushing power factors and capacitances should not vary by more than ten
percent of nameplate values. Any hot collar watts-loss results that exceed
the test equipment manufacturer's recommendations should be
investigated.
8.
The regulation shall be a linear ratio throughout the range between the
maximum raise and the maximum lower positions.
7.

1.
Voltage (cont.)
2.
9.
2.
10.
If winding-resistance measurements vary by more than one percent from

adjacent windings, consult manufacturer.
11.
Evaluate results of dissolved gas analysis in accordance with ANSI/IEEE

C57.104.
12.
Current - Reserved
MTS-1997 103
7.

3.
Load Tap-Changers
1.

1.
2.
3.
Verify correct auxiliary device operation.
4.
Verify motor and drive train for correct operation and automatic motor
cutoff at maximum lower and maximum raise.
5.
Verify correct liquid level in all tanks.
6.

the manufacturer.
7.
Visually inspect wear/erosion indicators on vacuum bottles, if applicable.
8.
Verify operation of heaters.
9.
10.
104 MTS-1997

1.
Remove oil.
2.
Clean carbon residue and debris from compartment.
3.
Inspect contacts for wear and alignment.
4.
Inspect all electrical and mechanical connections for tightness

using calibrated torque wrench method in accordance with
5.
Inspect tap changer compartment terminal board, contact support

boards, and insulating operating components for evidence of
moisture, cracks, excessive wear, breakage, and/or signs of
electrical tracking.
6.
Electrically operate tap change through full range of taps.
7.
Replace gaskets and seal compartment.
8.
Fill with filtered oil.
7.

3.
Load Tap-Changers (cont.)
11.
required.
12.
Lubrication
13.
2.
1.

parts.
2.
Electrical Tests
1.
Perform insulation-resistance tests on each winding to ground in any offneutral position.
2.
Perform insulation power-factor/dissipation-factor tests in accordance with

Section 7.2.
*3.
Perform winding-resistance test at all tap positions.
4.
Perform special tests and adjustments as recommended by the

manufacturer.
5.
Perform turns-ratio test at all tap positions.
6.
Remove a sample of insulating liquid in accordance with ASTM D923. The

sample shall be tested for the following in accordance with the referenced
standard.
1.
2.
3.
* Optional
MTS-1997 105
7.

3.
Load Tap-Changers (cont.)
7.
Remove a sample of insulating liquid in accordance with ASTM D3613

and perform dissolved gas analysis (DGA) in accordance with ANSI/IEEE
C57.104 or ASTM D3612.
NOTE: Although there is no ANSI/IEEE standard for evaluating dissolved
gas in regulator, and load tap changer interrupter compartments, studies
have indicated there is value in comparing dissolved gases in the oil from
similarly designed regulators and load-tap changers.
8.
3.
106 MTS-1997
Perform vacuum bottle integrity test (overpotential), if applicable, across

each vacuum bottle with the contacts in the open position in strict
accordance with manufacturer's published data. Do not exceed
maximum voltage stipulated for this test.
Test Values
1.

2.
Insulation-resistance values at one minute should not be less than values

3.
4.
Turns ratio test results shall maintain a normal deviation between each
voltage step and shall not deviate more than one-half percent from the
calculated voltage ratio.
5.
Maximum winding insulation power factor/dissipation factor of liquid-filled

transformers corrected to 20C shall be in accordance with manufacturer's
specifications. Representative values are indicated in Table 10.3. Also,
compare with test equipment manufacturer's published data.
6.
Consult manufacturer if winding-resistance test results vary more than

one percent from test results of adjacent windings.
7.
8.
Compare results of dissolved gas analysis to previous test results.
7.

7.13 Grounding Systems
1.

1.
2.
3.
Verify ground system.
Electrical Tests
1.
Perform fall-of-potential test or alternative in accordance with IEEE

Standard 81 on the main grounding electrode or system.
2.
Perform point-to-point tests to determine the resistance between the main

grounding system and all major electrical equipment frames, system
neutral, and/or derived neutral points.
Test Values
1.
The resistance between the main grounding electrode and ground should
be no greater than five ohms for commercial or industrial systems and one
ohm or less for generating or transmission station grounds unless
otherwise specified by the owner. (Reference ANSI/IEEE Standard 142)
2.
Investigate point-to-point resistance values which exceed 0.5 ohm.
MTS-1997 107
7.

7.14 Ground-Fault Protection Systems
1.

1.
2.
2.
1.
Verify that ground connection is made ahead of neutral disconnect

link and on the line side of any ground fault sensor.
2.
Verify that neutral sensors are connected with correct polarity on

both primary and secondary.
3.
Verify that all phase conductors and the neutral pass through the
sensor in the same direction for zero sequence systems.
4.
Verify that grounding conductors do not pass through zero

sequence sensors.
5.
Verify that the grounded conductor is solidly grounded.
1.

7.14.2.2 (Electrical Tests).
2.

3.
3.
Verify correct operation of all functions of the self-test panel.
4.
Verify pickup and time-delay settings.
Electrical Tests
1.
108 MTS-1997
Visually inspect the components for damage and errors in polarity or

conductor routing.
Measure the system neutral-to-ground insulation resistance with the

neutral disconnect link temporarily removed. Replace neutral disconnect
link after testing.
7.

7.14 Ground-Fault Protection Systems (cont.)
2.

3.
Perform the following pickup tests using primary injection:
4.
3.
1.
Verify that the relay does not operate at 90 percent of the pickup
setting.
2.
Verify pickup is less than 125 percent of setting or 1200 amperes,

whichever is smaller.
For summation type systems utilizing phase and neutral current

transformers, verify correct polarities by applying current to each phaseneutral current transformer pair. This test also applies to molded-case
breakers utilizing an external neutral current transformer.
1.
Relay should operate when current direction is the same relative to

polarity marks in the two current transformers.
2.
Relay should not operate when current direction is opposite relative

to polarity marks in the two current transformers.
5.
Measure time delay of the relay at 150 percent or greater of pickup.
6.
Verify reduced control voltage tripping capability is 55 percent for ac

systems and 80 percent for dc systems.
7.
Verify blocking capability of zone interlock systems.
Test Values
1.
2.

3.
MTS-1997 109
7.

7.14 Ground-Fault Protection Systems (cont.)
110 MTS-1997
4.
System neutral-to-ground insulation shall be a minimum of one megohm.
5.
Insulation resistance values shall be in accordance with Table 10.1.
6.
Relay timing shall be in accordance with manufacturer's specifications but

must be no longer than one second at 3000 amperes.
7.

7.15 Rotating Machinery
1.
Motors
1.
AC Motors
1.
2.

1.
2.
Inspect for correct anchorage, mounting, grounding, and connection.
3.
1.

2.

3.
4.
Perform special tests such as air gap spacing and pedestal

alignment, if applicable.
Electrical Tests - Induction Motors

1.

2.
Perform insulation-resistance tests in accordance with ANSI/IEEE

Standard 43.
3.
*4.
1.
Motors larger than 200 horsepower:

Test duration shall be for ten minutes. Calculate polarization index.
2.
Motors 200 horsepower and less:

Test duration shall be for one minute. Calculate the dielectricabsorption ratio.
Perform dc overpotential tests on motors rated at 1000 horsepower and

greater and at 4000 volts and greater in accordance with ANSI/IEEE
Standard 95.
Perform insulation power-factor or dissipation-factor tests.
* Optional
MTS-1997 111
7.

7.15 Rotating Machinery (cont.)
1.
Motors (cont.)
1.
AC Motors (cont.)
*5.
6.
Perform insulation-resistance test on pedestal in accordance with

7.
Test surge protection devices in accordance with Section 7.19.
8.
Test motor starter in accordance with Section 7.16 prior to re-energizing

the motor.
9.
Verify that resistance temperature detector (RTD) circuits conform to

drawings. Verify that metering or relaying devices using the RTD's have
the correct rating.
10.
Verify that the motor space heater is functional.
11.
Perform a rotation test to insure correct shaft direction if the motor has
been electrically disconnected.
12.
Measure running current and evaluate relative to load conditions and

nameplate full-load amperes.
*13.
3.
*2.
112 MTS-1997
Perform vibration tests:

1.

Perform vibration test. Plot amplitude versus frequency.
2.

Perform vibration amplitude test.
Electrical Tests - Synchronous Motors

1.
* Optional
Perform surge comparison tests.
Perform all tests as indicated in Section 7.15.1.2 for induction motors.

Perform a voltage-drop test on all salient poles.
3.
Perform insulation-resistance tests on the main rotating field winding, the

exciter-field winding, and the exciter-armature winding in accordance with
ANSI/IEEE Standard 43.
*4.
Perform a high-potential test on the excitation system in accordance with

ANSI/IEEE Standard 421B.
7.

1.
Motors (cont.)
1.
AC Motors (cont.)
5.
*6.
Measure and record resistance of motor field winding, exciter-stator

winding, exciter-rotor windings, and field discharge resistors.
Perform front-to-back resistance tests on diodes and gating tests of silicon
controlled rectifiers for field application semiconductors.
7.
Prior to re-energizing, apply voltage to the exciter supply and adjust

exciter-field current to nameplate value.
8.
Verify that the field application timer and the enable timer for the powerfactor relay have been tested and set to the motor drive manufacturer's
recommended values.
*9.
Record stator current, stator voltage, and field current by strip chart
recorder for the complete acceleration period including stabilization time
for a normally loaded starting condition. From the recording determine the
following information:
1.
Bus voltage prior to start.
2.
Voltage drop at start.
3.
Bus voltage at motor full-load.
4.
Locked-rotor current.
5.
Current after synchronization but before loading.
6.
Current at maximum loading.
7.
Acceleration time to near synchronous speed.
8.
RPM just prior to synchronization.
9.
Field application time.
10.
Time to reach stable synchronous operation.
*10.
Plot a V-curve of stator current versus excitation current at approximately

50 percent load to check correct exciter operation.
*11.
If the range of exciter adjustment and motor loading permit reduce

excitation to cause power factor to fall below the trip value of the powerfactor relay. Verify relay operation.
* Optional
MTS-1997 113
7.

1.
Motors (cont.)
1.
AC Motors (cont.)
4.
Test Values
1.
2.

3.
4.
Insulation-resistance test results shall be in accordance with values listed

in Table 10.1 Investigate dielectric absorption ratios less than 1.4 and
polarization index ratios less than 2.0 for Class B and Class F insulation.
NOTE: Overpotential, high-potential, and surge comparison tests shall
not be made on motors having values lower than those indicated above.
5.
Stator winding dc overpotential test voltage shall be in accordance with

ANSI/NEMA MG 1, paragraph 3.01. Test results are dependent on
ambient conditions, and evaluation is on a withstand basis. If phase
windings can be separately tested, values of leakage current may be
compared for similar windings.
6.
Vibration amplitudes shall not exceed values shown in Table 10.10.
7.
Salient pole voltage drop should be equal for each pole. For direct current
tests each pole (or pair of poles) should not vary more than two percent
from the average.
NOTE: An ac test is more sensitive in determining shorted turns. A pole
with shorted turns will have a substantially lower voltage than sound coils.
Coils adjacent to coils with shorted turns will exhibit slightly lower voltage.
8.
114 MTS-1997
The measured resistance values of motor-field windings, exciter-stator

windings, exciter-rotor windings, and field-discharge resistors shall be
compared to manufacturer's recommended values.
7.

1.
Motors (cont.)
2.
DC Motors
1.
2.

1.
2.
Inspect for correct anchorage, mounting, grounding, and connection.
3.
1.

2.

3.
4.
Inspect brushes and brush rigging.
5.
Perform special tests such as air gap spacing and pedestal alignment, if
applicable.
Electrical Tests
1.

2.
Perform insulation-resistance tests on all windings in accordance with

ANSI/IEEE Standard 43.
3.
1.

Test duration shall be for ten minutes. Calculate polarization index.
2.

Test duration shall be for one minute. Calculate the dielectric
absorption ratio.
Perform high-potential test in accordance with NEMA MG 1, paragraph

3.01.
MTS-1997 115
7.

1.
Motors (cont.)
2.
DC Motors (cont.)
*4.
Perform a voltage-drop test on all field poles.
*5.
Perform insulation power-factor or dissipation-factor tests.
6.
*7.
8.
3.
Measure armature running current and field current or voltage. Compare

to nameplate.
Perform vibration tests:
1.

Perform vibration test. Plot amplitude versus frequency.
2.

Perform vibration amplitude test.
Verify that all protective devices are in accordance with Section 7.16.
Test Values
1.
2.

3.
4.
Insulation-resistance test values shall be in accordance with those listed

in Table 10.1. Investigate dielectric absorption ratios less than 1.4 and
polarization index ratios less than 2.0 for Class B and Class F insulation.
NOTE: Overpotential, high-potential, and surge comparison tests shall
not be made on motors having values lower than those indicated above.
2.
* Optional
116 MTS-1997
5.
Overpotential test evaluation shall be on a withstand basis.
6.
Vibration amplitudes shall not exceed values shown in Table 10.10.
Generators - Reserved
7.

7.16 Motor Control
1.
Motor Starters
1.
Low-Voltage
1.

1.
2.
Inspect contactors.
1.
Verify mechanical operation.
2.
Inspect and adjust contact gap, wipe, alignment, and pressure in

*3.
4.
Motor-Running Protection
1.
Compare overload element rating with motor full-load current

rating to verify correct sizing.
2.
If power-factor correction capacitors are connected on the

load side of the overload protection, include the effect of the
capacitive reactance in determining appropriate overload
element size.
3.
If motor-running protection is provided by fuses, verify

correct fuse rating considering motor characteristics and
power-factor correction capacitors.
Inspect all bolted electrical connections for high resistance using

one of the following methods:
1.

2.
Verify tightness of accessible bolted electrical connections

by calibrated torque-wrench method in accordance with
3.
* Optional
MTS-1997 117
7.

7.16 Motor Control (cont.)
1.
Motor Starters (cont.)
1.
Low-Voltage (cont.)
2.
5.
Thoroughly clean unit prior to testing unless as-found and as-left

tests are required.
6.
Lubrication
1.
Verify appropriate contact lubricant on moving currentcarrying parts.
2.
Verify appropriate lubrication on moving and sliding

surfaces.
Electrical Tests
1.

2.
Measure insulation resistance of each combination starter, phase-tophase and phase-to-ground, with the starter contacts closed and the
protective device open. Test voltage shall be in accordance with Table
10.1. Refer to manufacturer's published data for devices with solid-state
components.
*3.
4.
Perform an insulation-resistance test at 1000 volts dc on all control wiring.

recommendations.
Test the motor overload relay elements by injecting primary current
through the overload circuit and monitoring trip time of the overload
element.
NOTE: Test times for thermal trip units will, in general, be longer than
manufacturer's curve if single-pole testing is performed. Optionally test
with all poles in series for time test and each pole separately for
comparison. (Refer to ANSI/NEMA ICS 2, Part 4.)
* Optional
118 MTS-1997
5.
Test circuit breakers in accordance with Section 7.6.1.1.
6.
Perform operational tests by initiating control devices.
7.

1.
1.
Low-Voltage (cont.)
3.
Test Values
1.
2.

3.
4.
Insulation-resistance values shall be in accordance with Table 10.1.
5.
Control wiring insulation test resistance shall be a minimum of two

megohms.
6.
Overload trip times shall be in accordance with manufacturer's published

data.
MTS-1997 119
7.

1.
2.
Medium-Voltage
1.
120 MTS-1997

1.
Inspect physical, electrical, and mechanical condition, including evidence

of moisture and/or corona.
2.
1.

2.

3.
3.
and sequencing.
4.
Verify correct barrier and shutter installation and operation.
5.
Exercise all active components and confirm correct operation of all

indicating devices.
6.
Inspect contactors.
1.
Verify mechanical operation.
2.
Inspect and adjust contact gap, wipe, alignment, and pressure in

7.
Compare overload protection rating with motor nameplate to verify correct

size. Set adjustable or programmable devices according to the protective
device coordination study.
8.
required.
7.

1.
2.
9.
2.
Lubrication
1.

parts.
2.
Electrical Tests
1.

*2.
Perform system function tests at 1000 volts dc on all control wiring. For
units with solid-state components, follow manufacturer's
recommendations.
3.
Perform system function test in accordance with Section 8.
4.
Test control power transformers in accordance with Section 7.1.2.8.
5.
Perform insulation-resistance tests on contactor(s), phase-to-ground,

phase-to-phase, and across the open contacts for one minute in
accordance with Table 10.1.
*6.

data. If manufacturer has no recommendation for this test, it shall be in
7.

each vacuum bottle with the contacts in the open position in strict
maximum voltage stipulated for this test.
8.
9.
Measure blowout coil circuit resistance.
* Optional
MTS-1997 121
7.

1.
2.
10.
Measure resistance of power fuses.
11.
Energize contactor using an auxiliary source. Adjust armature to minimize

operating vibration where applicable.
12.
Test motor overload relay elements by injecting primary current through

overload circuit and monitoring trip time of the overload element.
NOTE: Test times for thermal trip units will, in general, be longer than
manufacturer's curve if single-pole testing is performed. Optionally test
with all poles in series for time test and each pole separately for
comparison.
3.
122 MTS-1997
13.
Test ground-fault protection by injecting primary current through sensor.

Confirm pickup level and timing.
14.
If solid-state or microprocessor-type protective relaying is used, test in

accordance with Section 7.9.
15.
Verify operation of cubicle space heater.
Test Values
1.
2.
Bolt-torque values shall be in accordance with Table 10.12 unless

3.
4.
Starter insulation resistance shall be in accordance with Table 10.1.
5.
7.

1.
2.
6.
7.
Resistance values shall not deviate by more than 15 percent between

identical fuses.
8.
Overload trip times shall be in accordance with manufacturer's published

data.
MTS-1997 123
7.

2.
Motor Control Centers
1.
Low-Voltage
2.
2.
1.
Refer to Section 7.1, Switchgear and Switchboard Assemblies, for

appropriate inspections and tests of the motor control center bus.
2.
Refer to Section 7.5.1.1, Low-Voltage Switches, for appropriate

inspections and tests of the motor control center switches.
3.
Refer to Section 7.6.1, Low-Voltage Circuit Breakers, for appropriate

inspections and tests of the motor control center circuit breakers.
4.
Refer to Section 7.16.1, Low-Voltage Motor Starters, for appropriate

inspections and tests of the motor control center starters.
Motor Control Centers

Medium-Voltage
1.
Refer to Section 7.1, Switchgear and Switchboard Assemblies, for

appropriate inspections and tests of the motor control center bus.
2.
Refer to Section 7.5.1.2, Medium-Voltage Air Switches, for appropriate

inspections and tests of the motor control center switches.
3.
Refer to Section 7.6.2, Medium-Voltage Circuit Breakers, for appropriate

inspections and tests of the motor control center circuit breakers.
4.
Refer to Section 7.16.2, Medium-Voltage Motor Starters, for appropriate

inspections and tests of the motor control center starters.
7.17 Variable Frequency Drives - Reserved
124 MTS-1997
7.

7.18 Direct-Current Systems
1.
Batteries
1.
2.

1.
2.
1.

2.

3.
3.
Clean corroded/oxidized terminals and apply an oxide inhibitor.
4.
Verify electrolyte level.
5.
Verify presence of flame arresters.
6.
Verify adequacy of battery support racks, mounting, anchorage, and

clearances.
7.
Verify ventilation of battery room or enclosure.
8.
Verify existence of suitable eyewash equipment.
Tests
1.

2.
Measure electrolyte specific gravity and temperature.
3.
Measure charger float and equalizing voltage levels.
4.
Verify all charger functions and alarms.
5.
Measure each cell voltage and total battery voltage with charger
energized and in float mode of operation.
MTS-1997 125
7.

7.18 Direct-Current Systems (cont.)
1.
Batteries (cont.)
6.
Measure intercell connection resistances.
*7.
Perform cell impedance test.
*8.
Perform a capacity load test in accordance with manufacturer's

specifications or the following ANSI/IEEE standards:
ANSI/IEEE 450. Recommended Practice for Maintenance, Testing and
Replacement of Large Lead Storage Batteries for Generating Stations and
Substations.
ANSI/IEEE 1106. Recommended Practice for Maintenance, Testing and
Replacement of Nickel-Cadmium Storage Batteries for Generating
Stations and Substations.
3.
* Optional
126 MTS-1997
Test Values
1.
2.

3.
4.
Charger float and equalize voltage levels shall be in accordance with

5.
Specific gravity shall be in accordance with manufacturer's recommended

values.
6.
Electrolyte level shall be within normal limits.
7.
Cell voltages should be within 0.05 volt of each other or in accordance

with manufacturer's published data.
8.
Cell impedance or conductance values should not vary by more than 25

percent between identical cells that are in a fully charged state.
7.

7.18 Direct-Current Systems
2.
Chargers
1.
2.
3.
3.

1.
Inspect for damage and moisture contamination.
2.
1.

2.

3.
Electrical Tests
1.

2.
Verify float voltage and equalized voltage settings.
3.
Verify operation of ammeter.
4.
Verify operation of alarms.
Test Values
1.
2.
Bolt-torque levels shall be in accordance with manufacturer's published

data or Table 10.12.
3.
4.
Float and equalize voltage settings shall be in accordance with

Rectifiers - Reserved
MTS-1997 127
7.

7.19 Surge Arresters
1.
Low-Voltage Surge Protection Devices
1.

1.
2.
Inspect for correct mounting and adequate clearances.
3.
4.
2.
128 MTS-1997
1.

2.

3.
Verify that the ground lead on each device is individually attached to a

ground bus or ground electrode.
Electrical Tests
1.

2.
Perform insulation-resistance tests. Use manufacturer's recommended

values or Table 10.1.
3.
Test grounding connection in accordance with Section 7.13.
7.

7.19 Surge Arresters (cont.)
1.
Low-Voltage Surge Protection Devices (cont.)
3.
Test Values
1.
2.

3.
4.
Insulation-resistance values shall be in accordance with Table 10.1.
5.
Resistance between the arrester ground terminal and the ground system
shall be less than 0.5 ohm.
MTS-1997 129
7.

2.
Medium- and High-Voltage Surge Protection Devices
1.
2.

1.
2.
Inspect for correct mounting and adequate clearances.
3.
2.

3.
Verify that the ground lead on each device is individually attached to a

ground bus or ground electrode.
5.
Verify that stroke counter, if present, is correctly mounted and electrically

connected.
Electrical Tests
1.
Test grounding connection in accordance with Section 7.13.
2.

4.
130 MTS-1997

4.
*3.
* Optional
1.
Perform a watts-loss test.

Perform an insulation-resistance test at voltage levels in Table 10.1.
7.

2.
Medium- and High-Voltage Surge Protection Devices (cont.)
3.
Test Values
1.
2.

3.
4.
Resistance between the arrester ground terminal and the ground system
shall be less than 0.5 ohm.
5.
Compare watts loss to similar units.
6.
Insulation-resistance values should be in accordance with Table 10.1.
MTS-1997 131
7.

7.20 Capacitors and Reactors
1.
Capacitors
1.
2.
132 MTS-1997

1.
2.
Inspect capacitors for correct mounting and required clearances.
3.
Verify that capacitors are electrically connected in their specified

configuration.
4.
1.

2.

3.
Electrical Tests
1.
Perform insulation-resistance tests from terminal(s) to case for one minute

on capacitors with more than one bushing. Test voltage and minimum
resistance shall be in accordance with manufacturer's published data or
Table 10.1.
2.

low-resistance ohmmeter, if applicable. See Section 7.20.1.1.4 (Visual
and Mechanical Inspection).
3.
Measure the capacitance of all terminal combinations.
4.
Measure resistance of internal discharge resistors.
7.

7.20 Capacitors and Reactors (cont.)
1.
Capacitors (cont.)
3.
Test Values
1.
2.

3.
4.
Insulation-resistance values less than Table 10.1 shall be investigated.
5.
Investigate capacitance values differing from manufacturer's published

data.
6.
Investigate discharge resistor values differing from manufacturer's

published data. In accordance with NEC Article 460, residual voltage of a
capacitor shall be reduced to 50 volts in the following time intervals after
being disconnected from the source of supply:
Rated Voltage
600 volts
> 600 volts
Discharge Time
1 minute
5 minutes
2.
Capacitor Control Devices - Reserved
3.
Reactors - Reserved
MTS-1997 133
7.

7.21 Outdoor Bus Structures
1.

1.
2.
3.
2.
2.

3.
Clean insulators.
1.

*2.
Measure insulation resistance of each bus, phase-to-ground with other

phases grounded.
4.
134 MTS-1997

Electrical Tests
3.
* Optional
1.
Perform overpotential test on each bus phase, phase-to-ground with other

phases grounded. Potential application shall be for one minute.
Measure resistance of bus section joints with low-resistance ohmmeter.
7.

7.21 Outdoor Bus Structures (cont.)
3.
Test Values
1.
2.
Bolt-torque levels shall be in accordance with manufacturer's published

data or Table 10.12.
3.
4.
Insulation-resistance tests shall be in accordance with Table 10.1.
5.
Overpotential test voltage shall be in accordance with manufacturer's

published data or Table 10.19. The insulation shall withstand the
overpotential test voltage applied.
6.
Compare measured bus connector joint resistance to an equal length of

bus and to similar connections.
MTS-1997 135
7.

7.22 Emergency Systems
1.
Engine Generator
NOTE: The prime mover is not addressed in these specifications.
1.
2.
3.
136 MTS-1997

1.
2.
Inspect correct anchorage and grounding.
Electrical and Mechanical Tests

1.
Perform an insulation-resistance test on generator winding with respect to

ground in accordance with ANSI/IEEE Standard 43. Calculate polarization
index.
2.
Test protective relay devices in accordance with Section 7.9.
3.
Functionally test engine shutdown for low oil pressure, overtemperature,

overspeed, and other features as applicable.
4.
Perform vibration test for each main bearing cap.
5.
Conduct performance test in accordance with NFPA Standard 110.
6.
Verify correct functioning of governor and regulator.
Test Values
1.
Polarization index values shall be in accordance with ANSI/IEEE Standard

43.
2.
Vibration levels shall be in accordance with manufacturer's published data

and compared to baseline data.
3.
Performance tests shall conform to manufacturer's published data and

ANSI/NFPA Standard 110.
7.

7.22 Emergency Systems (cont.)
2.
Uninterruptible Power Systems
NOTE: There are many configurations of uninterruptible power supply installations.
Some are as simple as a static switch selecting between two highly reliable sources,
while others are complex systems using a combination of rectifiers, batteries, inverters,
motor/generators, static switches and bypass switches. It is the intent of this
Specification to list possible tests and maintenance of the major components of the
system and more specifically the system as a whole. It is important that the
manufacturer's recommended maintenance be performed.
1.

1.
Inspect physical, electrical, and mechanical condition.
2.
Check for correct anchorage, required area clearances, and correct

alignment.
3.
4.
and sequencing.
5.
1.

2.

3.
6.
Thoroughly clean unit prior to tests unless as-found and as-left tests are
required.
7.
Check operation of forced ventilation.
8.
Verify that filters are in place and/or vents are clear.
MTS-1997 137
7.

2.
Uninterruptible Power Systems (cont.)
2.
Electrical Tests
1.

2.
Test static transfer from inverter to bypass and back. Use normal load, if
possible.
3.
Set free running frequency of oscillator.
4.
Test dc undervoltage trip level on inverter input breaker. Set according to

5.
Test alarm circuits.
6.
Verify sync indicators for static switch and bypass switches.
7.
Perform electrical tests for UPS system breakers in accordance with

Section 7.6.1.
8.
Perform electrical tests for UPS system automatic transfer switches in

accordance with Section 7.22.3.
9.
Perform electrical tests for UPS system batteries in accordance with

Section 7.18.
10.
138 MTS-1997
Perform electrical tests for UPS rotating machinery in accordance with

Section 7.15.
7.

2.
Uninterruptible Power Systems (cont.)
3.
Test Values
1.
2.

3.
4.
For breaker performance refer to Section 7.6.1.
5.
For automatic transfer switch performance refer to Section 7.22.3.
6.
For batteries refer to Section 7.18.
7.
For rotating machinery, refer to Section 7.15.
MTS-1997 139
7.

3.
Automatic Transfer Switches
1.
140 MTS-1997

1.
2.
Lubrication
1.

parts.
2.
3.
Verify that manual transfer warnings are attached and visible.
4.
Verify tightness of all control connections.
5.
1.

2.

3.
6.
Perform manual transfer operation.
7.
Verify positive mechanical interlocking between normal and

alternate sources.
7.

3.
Automatic Transfer Switches (cont.)
2.
Electrical Tests
1.
2.

3.
Perform insulation-resistance tests, phase-to-phase and phase-to-ground,

with switch in both source positions.
4.
Verify settings and operation of control devices.
5.
Calibrate and set all relays and timers in accordance with Section 7.9.
6.
Perform automatic transfer tests:
7.
1.
Simulate loss of normal power.
2.
Return to normal power.
3.
Simulate loss of emergency power.
4.
Simulate all forms of single-phase conditions.
Verify correct operation and timing of the following functions:

1.
Normal source voltage-sensing relays.
2.
Engine start sequence.
3.
Time delay upon transfer.
4.
Alternate source voltage-sensing relays.
5.
Automatic transfer operation.
6.
Interlocks and limit switch function.
7.
Time delay and retransfer upon normal power restoration.
8.
Engine cool down and shutdown feature.
MTS-1997 141
7.

3.
Automatic Transfer Switches (cont.)
3.
7.23
Test Values
1.
2.

3.
lowest value.
4.
Insulation-resistance test voltages and minimum values shall be in

Telemetry/Pilot Wire/Scada - Reserved
142 MTS-1997
7.

7.24 Automatic Circuit Reclosers and Line Sectionalizers
1.
Automatic Circuit Reclosers, Oil/Vacuum
1.

1.
2.
3.
Perform all mechanical operation and contact alignment tests on both the
recloser and its operating mechanism in accordance with manufacturer's
published data.
4.
5.
2.
1.

2.

3.
Inspect for correct insulating liquid level.
Electrical Tests
1.

2.
3.

ASTM D923. Sample shall be tested in accordance with the referenced
standard.
1.
2.
3.
MTS-1997 143
7.

7.24 Automatic Circuit Reclosures and Line Sectionalizers (cont.)
1.
Automatic Circuit Reclosers, Oil/Vacuum (cont.)
4.
Test all solid-state or electromechanical protective functions in

accordance with Section 7.9.
5.
Test all metering and instrumentation in accordance with Section 7.11.
6.

each vacuum bottle with the breaker in the open position in strict
maximum voltage stipulated for this test. Provide adequate barriers
and protection against x-radiation during this test. Do not perform this test
unless the contact displacement of each interrupter is within
manufacturer's tolerance. Be aware that some dc high-potential test sets
are half-wave rectified and may produce peak voltages in excess of the
breaker manufacturer's recommended maximum.
7.
Perform overpotential test on each pole-to-ground and pole-to-pole with

recloser in closed position.
*8.

recommendations.
*9.
Perform overall power-factor test.
*10.
3.
* Optional
144 MTS-1997
Perform power-factor test on each bushing equipped with power-factor

taps. Use hot-collar method if taps are not available.
Test Values
1.
2.

3.
from adjacent poles or similar reclosers by more than 25 percent of the
lowest value.
7.

7.24 Automatic Circuit Reclosures and Line Sectionalizers (cont.)
1.
Automatic Circuit Reclosers, Oil/Vacuum (cont.)
4.
Overpotential test voltages shall be in accordance with manufacturer's

recommendations or Table 10.15.
5.
Insulating liquid tests shall be in accordance with Table 10.4.
6.
7.
Dissipation-factor/power-factor test results and tank loss index should not

exceed the manufacturer's published data. In the absence of
reclosers.
8.

9.
Test values for protective functions shall be within manufacturer's

recommendations.
MTS-1997 145
7.

7.24 Automatic Circuit Reclosers and Line Sectionalizers (cont.)
2.
Automatic Line Sectionalizers, Oil
1.

1.
2.
3.
Perform all mechanical operation and contact alignment tests on both the
sectionalizer and its operating mechanism in accordance with
4.
5.
2.
146 MTS-1997
1.

2.

3.
Inspect for correct insulating liquid level.
Electrical Tests
1.

2.
3.
Remove a sample insulating liquid in accordance with ASTM D923.

1.
2.
3.
7.

7.24 Automatic Circuit Reclosers and Line Sectionalizers (cont.)
2.
Automatic Line Sectionalizers, Oil (cont.)
4.
*5.

recommendations.
6.
Test sectionalizer counting function by application of simulated fault

current (greater than 160 percent of continuous current rating).
7.
Test sectionalizer lockout function for all counting positions.
8.
Test for reset timing on trip actuator.
*9.
*10.
3.
Perform overpotential test on each pole-to-ground and pole-to-pole.
Perform overall power-factor test.

Perform power-factor test on each bushing equipped with power-factor
taps. Use hot-collar method if taps are not available.
Test Values
1.
2.

3.
from adjacent poles or similar sectionalizers by more than 25 percent of
the lowest value.
4.
Overpotential test voltages shall be in accordance with manufacturer's

recommendations or Table 10.16.
5.
Insulating liquid tests shall be in accordance with Table 10.4.
6.
7.
Dissipation-factor/power-factor test results and tank loss index should not

exceed the manufacturer's published data. In the absence of
line sectionalizers.
* Optional
MTS-1997 147
7.

7.25 Fiber-Optic Cables
1.

1.
2.
3.
148 MTS-1997
Field Test
1.
Perform cable length measurement and detect fiber fractures or other

defects through analysis of the backscattering signal with an optical time
domain reflectometer.
2.
Perform a continuity test to detect splice fractures or other defects through

analysis of the backscattering signal using the optical time domain
reflectometer.
3.
Perform attenuation measurement of the cable loss with a multimode

optical loss test set.
4.
Perform attenuation measurement of losses at each splice and connector.
Test Values
1.
Attenuation measurement (losses) shall be expressed in dB/km. Test shall

be performed at a propagation velocity of 830 nm for multimode fiber and
1300 nm for single-mode fiber.
2.
Bandwidth measurement shall be expressed in MHz/km. Test shall be

performed at a propagation velocity of 830 nm for multimode fiber and
1300 nm for single-mode fiber.
7.

7.26 Electrical Safety Equipment
Vehicle-Mounted Elevating and Rotating Aerial Devices (insulated bucket, platform, and
ladder trucks). Refer to ANSI/SIA A92.2.
1.

A qualified person shall inspect the mobile unit for defects in accordance with
ANSI/SIA A92.2, Section 8.2.4 (Periodic Inspection and Test).
2.
Electrical Tests
1.
2.
3.
3.
Perform overpotential tests in accordance with Section 5.4.3

(Periodic/Maintenance Test Procedures), ANSI/SIA A92.2. Determine
category of insulated aerial device:
1.
Category A: Used for bare-hand work and has lower test electrode
system.
2.
Category B: Used for rubber-glove work and has lower test

electrode system.
3.
Category C: Used for rubber-glove work and does not have lower
test electrode system. Rated for 46 kV and below.
Determine testing procedure:

1.
Test upper insulated boom in accordance with Section 5.4.3.1 of

ANSI/SIA A.92.2 for Category A and B aerial devices.
2.
Test upper insulated boom in accordance with Section 5.4.3.2 of

ANSI/SIA A92.2 for Category C aerial devices.
3.
Test lower insulated booms in accordance with Section 5.4.3.4 of

ANSI/SIA A92.2.
4.
Test insulating liners in accordance with Section 5.4.3.5 of

ANSI/SIA A92.2.
5.
Test aerial ladders in accordance with Section 5.4.3.3 of ANSI/SIA

A92.2.
Determine test voltages and duration in accordance with Table 10.11.
Test Values: Maximum currents should be less than indicated on Table 10.11.
MTS-1997 149
7.

7.27 Electrostatic/Electromagnetic Field Testing - Reserved
7.28 Special Systems - Reserved
150 MTS-1997
8.
SYSTEM FUNCTION TESTS

8.1
General
1.
Perform system function tests upon completion of equipment tests as defined in

Section 7. It is the purpose of system function tests to prove the correct
interaction of all sensing, processing, and action devices.
2.
Implementation
1.
Develop test parameters for the purpose of evaluating performance of all

integral components and their functioning as a complete unit within design
requirements and manufacturer's published data.
Perform these tests.
2.
Verify the correct operation of all interlock safety devices for fail-safe
functions in addition to design function.
3.
Verify the correct operation of all sensing devices, alarms, and indicating
devices.
MTS-1997 151
9.THERMOGRAPHIC SURVEY
9.1

1.
Inspect physical, electrical, and mechanical condition.
2.
Remove all necessary covers prior to thermographic inspection.
9.2
Equipment to be inspected shall include all current-carrying devices.
9.3
Provide report including the following:

1.
Discrepancies.
2.
Temperature difference between the area of concern and the reference area.
3.
Cause of temperature difference.
4.
Areas inspected. Identify inaccessible and/or unobservable areas and/or

equipment.
5.
Identify load conditions at time of inspection.
*6.
9.4
9.5
Provide photographs and/or thermograms of the deficient area.
Test Parameters
1.
Inspect distribution systems with imaging equipment capable of detecting a

minimum temperature difference of 1C at 30C.
2.
Equipment shall detect emitted radiation and convert detected radiation to visual
signal.
3.
Thermographic surveys should be performed during periods of maximum

possible loading but not less than 40 percent of rated load of the electrical
equipment being inspected. Refer to ANSI/NFPA 70B, Section 18-16 (Infrared
Inspection).
Test Results
Suggested actions based on temperature rise can be found in Table 10.18.
* Optional
152 MTS-1997
TABLE 10.1
Insulation Resistance Tests
on
Electrical Apparatus and Systems
Maximum Rating of
Equipment in Volts
Minimum Test Voltage, dc

in Volts
Recommended Minimum
Insulation Resistance in
Megohms
250
500
25
600
1,000
100
5,000
2,500
1,000
8,000
2,500
2,000
15,000
2,500
5,000
25,000
5,000
20,000
35,000
15,000
100,000
46,000
15,000
100,000
69,000
15,000
100,000
In the absence of consensus standards dealing with insulation-resistance tests, the NETA Technical Committee
suggests the above representative values.
See Table 10.14 for temperature correction factors.
Actual test results are dependent on the length of the conductor being tested, the temperature of the insulating
material, and the humidity of the surrounding environment at the time of the test. In addition, insulation resistance
tests are performed to establish a trending pattern and a deviation from the baseline information obtained during
maintenance testing enabling the evaluation of the insulation for confined use.
MTS-1997 153
TABLE 10.2
Switchgear Low-Frequency Withstand Test Voltages
Type of Switchgear
Rated Maximum Voltage
Maximum Test Voltage kV
(kV) (rms)
ac
dc
.254/.508/.635
1.6
2.3
MC
4.76
14.0
20.0
(Metal-Clad Switchgear)
8.25
27.0
37.0
15.0
27.0
37.0
38.0
60.0
SC
15.5
37.0
(Station-Type Cubicle
38.0
60.0
Switchgear)
72.5
120.0
MEI
4.76
14.0
20.0
(Metal-Enclosed
8.25
19.0
27.0
Interrupter Switchgear)
15.0
27.0
37.0
15.5
37.0
52.0
25.8
45.0
38.0
60.0
LV
(Low-Voltage Power
Circuit Breaker
Switchgear)
Derived from ANSI/IEEE C37.20.1-1993, Paragraph 5.5, Standard for Metal-Enclosed Low-Voltage Power Circuit-Breaker
Switchgear, C37.20.2-1993, Paragraph 5.5, Standard for Metal-Clad and Station-Type Cubicle Switchgear and C37.20.31993, Paragraph 5.5, Standard for Metal-Enclosed Interrupter Switchgear, and includes 0.75 multiplier with fraction rounded
down.
The column headed "DC" is given as a reference only for those using dc tests to verify the integrity of connected cable
installations without disconnecting the cables from the switchgear. It represents values believed to be appropriate and
approximately equivalent to the corresponding power frequency withstand test values specified for voltage rating of
switchgear. The presence of this column in no way implies any requirement for a dc withstand test on ac equipment or that a
dc withstand test represents an acceptable alternative to the low-frequency withstand tests specified in this specification,
either for design tests, production tests, conformance tests, or field tests. When making dc tests, the voltage should be
raised to the test value in discrete steps and held for a period of one minute.
Because of the variable voltage distribution encountered when making dc withstand tests, the manufacturer should be
contacted for recommendations before applying dc withstand tests to the switchgear. Voltage transformers above 34.5kV
should be disconnected when testing with dc. Refer to ANSI/IEEE C57-13-1978 (R1987) IEEE Standard Requirements for
Instrument Transformers [10], Section 8 and, in particular 8.8.2, (the last paragraph) which reads "Periodic kenotron tests
should not be applied to transformers of higher than 34.5 kV voltage rating."
+ Consult Manufacturer
154 MTS-1997
TABLE 10.3
Recommended Dissipation Factor/Power Factor
of Liquid-Filled Transformers
Oil
Maximum
Silicone
Maximum
Tetrachloroethylene
Maximum
High Fire Point

Hydrocarbon
Maximum
Power
Transformers
2.0%
0.5%
3.0%
2.0%
Distribution
Transformers
3.0%
0.5%
3.0%
3.0%
In the absence of consensus standards dealing with transformer dissipation factor/power factor values, the NETA
Technical Committee suggests the above representative values.
MTS-1997 155
TABLE 10.4
Suggested Limits for Service-Aged Insulating Fluids
Mineral Oil*
ASTM Method
69 kV and
Below
Above 69 kV
through 288 kV
345 kV and
Above
Dielectric breakdown, kV
minimum
D877
26
26
26
minimum @ 0.04 gap
D1816
23
26
26
minimum @ 0.08 gap
D1816
34
45
45
Interfacial tension, mN/m

minimum
D971
24
26
30
Neutralization number, mg
KOH/g maximum
D974
0.2
0.2
0.1
Water content, ppm maximum
D1533
35
25
20
Power factor at 25C, %
D924
1.0****
1.0****
1.0****
Power factor at 100 C, %
D924
1.0****
1.0****
1.0****
Test
ASTM Method
Silicone**
Less Flammable
Hydrocarbon***
Dielectric Breakdown, kV minimum
D877
25
24
Visual
D2129
Colorless, clear,
free of particles
N/A
Water Content, ppm maximum
D1533
100
45
Dissipation factor, % max. @ 25C
D924
0.2
1.0
Viscosity, cSt @ 25C
D445
47.5 - 52.5
N/A
Fire Point, C, minimum
D92
340
300
Neutralization number, mg KOH/g max.
D974
0.2
N/A
Neutralization number, mg KOH/g max.
D664
N/A
0.25
Interfacial Tension, mN/m minimum @ 25C
D971
N/A
22
Test
*
**
***
****
IEEE C57.106-1991 Guide for Acceptance and Maintenance of Insulating Oil in Equipment, Table 5.
IEEE C57.111-1989 Guide for Acceptance of Silicone Insulating Fluid and Its Maintenance in Transformers, Table
3.
IEEE C57.121-1988 Guide for Acceptance and Maintenance of Less Flammable Hydrocarbon Fluid in
Transformers, Table 3.
IEEE Standard. 637-1985 IEEE Guide for the Reclamation of Insulating Oil and Criteria for Its Use.
156 MTS-1997
TABLE 10.5
Transformer Insulation-Resistance
Recommended Minimum
Insulation Resistance in Megohms
Transformer Coil
Rating Type in Volts
Minimum dc Test
Voltage
Liquid Filled
Dry
0 - 600
1000
100
500
601 - 5000
2500
1000
5000
5001 - 15000
5000
5000
25000
In the absence of consensus standards, the NETA Technical Committee suggests the above representative values.
NOTE: Since insulation resistance depends on insulation rating (kV) and winding capacity (kVA), values obtained should
be compared to manufacturer's published data.
MTS-1997 157
TABLE 10.6
Medium-Voltage Cables
Maximum Maintenance Test Voltages (kV, dc)
Insulation Type
Rated Cable Voltage
Insulation Level
Test Voltage kV, dc
Elastomeric:
5 kV
100%
19
Butyl and Oil Base
5 kV
133%
19
15 kV
100%
41
15 kV
133%
49
25 kV
100%
60
Elastomeric:
5 kV
100%
19
EPR
5 kV
133%
19
8 kV
100%
26
8 kV
133%
26
15 kV
100%
41
15 kV
133%
49
25 kV
100%
60
25 kV
133%
75
28 kV
100%
64
35 kV
100%
75
Polyethylene
5 kV
100%
19
(see Note 4)
5 kV
133%
19
8 kV
100%
26
8 kV
133%
26
15 kV
100%
41
15 kV
133%
49
25 kV
100%
60
25 kV
133%
75
35 kV
100%
75
Derived from ANSI/IEEE Standard 141-1993 Table 12-9 and by factoring the applicable ICEA/NEMA Standards by 75% as
recommended in Section 18-9.2.4 of NFPA 70B, 1994 Edition Electrical Equipment Maintenance.
Refer to notes on the following page.
158 MTS-1997
TABLE 10.6 - NOTES

NOTE 1:
Selection of test voltage for in-service cables depends on many factors. The owner should be consulted
and/or informed of the intended test voltage prior to performing the test. Caution should be used in
selecting the maximum test voltage and performing the test since cable failure during the test will require
repair or replacement prior to re-energizing.
NOTE 2:
AEIC C55 and C56 list test voltages approximately 20 percent higher than the ICEA values for the first five
years of service. These values are based on 65 percent of the factory test voltages. A reduction to 40
percent is recommended for a cable in service longer than five years.
NOTE 3:
ANSI/IEEE 400-1991 specifies much higher voltages than either the ICEA or the AEIC. These voltages
overstress cables and are intended to find marginal cable during shutdown to avoid in-service failures.
These test voltages should not be used without the concurrence of the owner. If the cable is still in
warranty, the cable manufacturer should be consulted for their concurrence. (See the Standard for a
discussion of the pros and cons of high direct-voltage tests.)
NOTE 4:
See Electric Power Research Institute Report, EPRI TR-101245, "Effect of DC Testing on Extruded
Cross-Linked Polyethylene Insulated Cables." DC high potential testing of aged XLPE-insulated cable in
wet locations may reduce remaining life.
MTS-1997 159
TABLE 10.7
Molded-Case Circuit Breakers
Values for Inverse Time Trip Test
(At 300% of Rated Continuous Current of Circuit Breaker)
Range of Rated Continuous
Current Amperes
Maximum Trip Time in Seconds

1
For Each Maximum Frame Rating
250V
251 - 600V
0-30
50
70
31-50
80
100
51-100
140
160
101-150
200
250
151-225
230
275
226-400
300
350
401-600
------------
450
601-800
------------
500
801-1000
------------
600
1001-1200
------------
700
1201-1600
------------
775
1601-2000
------------
800
2001-2500
------------
850
2501-5000
------------
900
Reproduction of Table 5-3 from NEMA Standard AB4-1991.

1
For integrally-fused circuit breakers, trip times may be substantially longer if tested with the fuses replaced by solid links
(shorting bars).
160 MTS-1997
TABLE 10.8
Instantaneous Trip Setting Tolerances
for Field Testing
of Marked Adjustable Trip Circuit Breakers
Tolerances of High and Low Settings
Ampere Rating
High
Low
250
+40%
-25%
+40%
-30%
>250
25%
30%
Reproduction of Table 5-4 from NEMA publication AB4-1991.

For circuit breakers with nonadjustable instantaneous trips, tolerances apply to the manufacturer's published trip range,
i.e., +40 percent on high side, -30 percent on low side.
MTS-1997 161
TABLE 10.9
Instrument Transformer Dielectric Tests
Field Maintenance
Nominal System (kV)
BIL
(kV)
Periodic Dielectric Withstand Test

Field Test Voltage (kV)
ac
dc
0.6
10
2.6
1.1
30
6.5
10
2.4
45
9.7
15
4.8
60
12.3
19
8.32
75
16.9
26
13.8
95
22.1
34
13.8
110
22.1
34
25
125
26.0
40
25
150
32.5
50
34.5
150
32.5
50
34.5
200
45.5
70
46
250
61.7
69
350
91.0
115
450
120.0
115
550
149.0
138
550
149.0
138
650
178.0
161
650
178.0
161
750
211.0
230
900
256.0
230
1050
299.0
Table 10.9 is derived from Paragraph 8.8.2 and Tables 2 and 7 of ANSI/IEEE C57.13, "Standard Requirements for
Instrument Transformers."
+ Periodic dc potential tests are not recommended for transformers rated higher than 34.5 kV.
* Under some conditions transformers may be subjected to periodic insulation test using direct voltage from kenotron sets.
In such cases the test direct voltage should not exceed the original factory test rms alternating voltage. Periodic kenotron
tests should not be applied to (instrument) transformers of higher than 34.5 kV voltage rating.
162 MTS-1997
TABLE 10.10
Maximum Allowable Vibration Amplitude
Speed - RPM
Amplitude - Inches Peak to Peak
3000 and above
0.001
1500 - 2999
0.002
1000 - 1499
0.0025
999 and below
0.003
Derived from NEMA publication MG 1-1993, Sections 20.53, 21.54, 22.54, 23.52, and 24.50.
MTS-1997 163
TABLE 10.11
Periodic Electrical Test Values for Insulating Aerial Devices
Insulating Aerial Devices with a Lower Test Electrode System
(Category A and Category B)
Unit Rating
60 Hertz (rms) Test
Direct Current Test
Voltage kV
(rms)
Maximum
Allowable
Current
Microamperes
Time
Voltage kV
Maximum
Allowable
Current
Microamperes
Time
46 kV & below
40
40
1 minute
56
28
3 minutes
69 kV
60
60
1 minute
84
42
3 minutes
138 kV
120
120
1 minute
168
84
3 minutes
230 kV
200
200
1 minute
240
120
3 minutes
345 kV
300
300
1 minute
360
180
3 minutes
500 kV
430
430
1 minute
602
301
3 minutes
765 kV
660
660
1 minute
924
462
3 minutes
Insulating Aerial Devices without Lower Test Electrode System

(Category C)
Error!
Bookmark not
defined.Unit
Rating
46 kV & below
60 Hertz (rms) Test
Direct Current Test
Voltage kV
(rms)
Maximum
Allowable Current
Microamperes
Time
Voltage kV
Maximum
Allowable Current
Microamperes
Time
40
400
1 minute
56
56
3 minutes
Insulating Aerial Ladders and Insulating Vertical Aerial Towers

Unit Rating
60 Hertz (rms) Test
Direct Current Test
Voltage kV
(rms)
Maximum
Allowable Current
Microamperes
Time
Voltage kV
Maximum
Allowable Current
Microamperes
Time
46 kV & below
40
400
1 minute
56
56
3
minutes
20 kV & below
20
200
1 minute
28
28
3
minutes
164 MTS-1997
TABLE 10.11 (cont.)

Chassis Insulating Systems
Lower Insulated Booms
60 Hertz (rms) Test
Direct Current Test
Voltage kV
(rms)
Maximum
Allowable Current
Milliamperes
Time
Voltage kV
Maximum
Allowable Current
Microamperes
Time
35
3.0
3 minutes
50
50
3 minutes
NOTE:
1.
Derived from ANSI/SIA A92-2-1990.
2.
A method of calculating test voltages for units rated other than those tabulated here is as follows:
1.
The 60 Hz test values are equal to line to ground at the unit rating value time 1.5.
2.
Multiply the 60 Hz test values times 1.4 to arrive at the direct current values.
MTS-1997 165
TABLE 10.12
US Standard
Heat-Treated Steel - Cadmium or Zinc Plated
Grade
SAE 1 & 2
SAE 5
SAE 7
SAE 8
Minimum Tensile
(P.S.I.)
64K
105K
133K
150K
Bolt Diameter
In Inches
Torque (Foot Pounds)
1/4
4.0
5.6
8.0
8.4
5/16
7.2
11.2
15.2
17.6
3/8
12.0
20.0
27.2
29.6
7/16
19.2
32.0
44.0
48.0
1/2
29.6
48.0
68.0
73.6
9/16
42.4
70.4
96.0
105.6
5/8
59.2
96.0
133.6
144.0
3/4
96.0
160.0
224.0
236.8
7/8
152.0
241.6
352.0
378.4
1.0
225.6
372.8
528.0
571.2

Silicon Bronze Fasteners1
Torque (Foot-Pounds)
Bolt Diameter in Inches
Nonlubricated
Lubricated
5/16
15
10
3/8
20
14
1/2
40
25
5/8
55
40
3/4
70
60
Bronze alloy bolts shall have a minimum tensile strength of 70,000 pounds per square inch.
166 MTS-1997
TABLE 10.12 (cont.)

2
Aluminum Alloy Fasteners
Lubricated
5/16
8.0
3/8
11.2
1/2
20.0
5/8
32.0
3/4
48.0
Aluminum alloy bolts shall have a minimum tensile strength of 55,000 pounds per square inch.

Stainless Steel Fasteners3
Uncoated
5/16
14
3/8
25
1/2
45
5/8
60
3/4
90
Bolts, cap screws, nuts, flat washers, locknuts: 18-8 alloy. Belleville washers: 302 alloy.
MTS-1997 167
Table 10.13
SF6 Gas Tests
Test
Test Limits
Moisture by hygrometer method
Per manufacturer or investigate greater than

(1)
200 ppm
SF6 decomposition byproducts

by ASTM D2685
Greater than 500 ppm (2)
Air by ASTM D-2685
Greater than 5000 ppm
Dielectric Breakdown
using hemispherical contacts at 0.10 inch
gap at atmospheric pressure
11.5 - 13.5 kV
(1)
(2)
(3)
(4)
(3)
(4)
According to some manufacturers.

In the absence of consensus standards dealing with SF6 circuit breaker gas tests, the NETA Technical
Committee suggests the above representative values.
Dominelli, N. and Wylie, L., Analysis of SF6 Gas as a Diagnostic Technique for GIS, Electric Power Research
Institute, Substation Equipment Diagnostics Conference IV, February 1996.
Per Even, F.E., and Mani, G. "Sulfur Fluorides", Kirk-Othmer Encyclopedia of Chemical Technology, 4th ed.,
11,428, 1994.
168 MTS-1997
TABLE 10.14
Insulation Resistance
Conversion Factors
For Conversion of Test
Temperature to 20C
Temperature
C
Multiplier
F
Apparatus Containing
Immersed Oil Insulations
Apparatus Containing
Solid Insulations
32
0.25
0.40
41
0.36
0.45
10
50
0.50
0.50
15
59
0.75
0.75
20
68
1.00
1.00
25
77
1.40
1.30
30
86
1.98
1.60
35
95
2.80
2.05
40
104
3.95
2.50
45
113
5.60
3.25
50
122
7.85
4.00
55
131
11.20
5.20
60
140
15.85
6.40
65
149
22.40
8.70
70
158
31.75
10.00
75
167
44.70
13.00
80
176
63.50
16.00
MTS-1997 169
TABLE 10.15
High-Potential Test Voltage
for Automatic Circuit Reclosers
Nominal Voltage
Class, kV
Maximum Voltage, kV
Rated Impulse
Withstand Voltage, kV
Maximum Field Test

Voltage, kVac
14.4 (1 and 3)
15.0
95
26.2
14.4 (1 and 3)
15.5
110
37.5
24.9 (1 and 3)
27.0
150
45.0
34.5 (1 and 3)
38.0
150
52.5
46.0 (3)
48.3
250
78.7
69.0 (3)
72.5
350
120.0
Derived from ANSI/IEEE C37.61-1973(R1993) (Standard Guide for the Application, Operation, and Maintenance
of Automatic Circuit Reclosers), C37.60-1981(R1993) (Standard Requirements for Overhead, Pad-Mounted, DryVault, and Submersible Automatic Circuit Reclosers and Fault Interrupters for AC Systems).
170 MTS-1997
TABLE 10.16
High-Potential Test Voltage
for Periodic Test of Line Sectionalizers
Nominal Voltage
Class kV
Maximum
Voltage kV
Rated Impulse
Withstand
Voltage kV
Maximum Field
Test Voltage
kVAC
DC 15 Minute
Withstand (kV)
14.4 (1)
15.0
95
26.2
39
14.4 (1)
15.0
125
31.5
39
14.4 (3)
15.5
110
37.5
39
24.9 (1)
27.0
125
45.0
58
34.5 (3)
38.0
150
52.5
77
Derived from ANSI/IEEE C37.63-1984(R1990) Table 2 (Standard Requirements for Overhead, Pad-Mounted, Dry-Vault,
and Submersible Automatic Line Sectionalizers of AC Systems).
The table includes a 0.75 multiplier with fractions rounded down.
NOTE: Values of ac voltage given are dry test one minute factory test values.
MTS-1997 171
Table 10.17
Metal-Enclosed Bus Dielectric Withstand Test Voltages
Type of Bus
Rated kV
Maximum Test Voltage, kV

ac
dc
Isolated Phase for Generator Leads
24.5
29.5
34.5
37.0
45.0
60.0
52.0
---
Isolated Phase for Other than

Generator Leads
15.5
25.8
38.0
37.0
45.0
60.0
52.0
---
Nonsegregated Phase
0.635
4.76
15.0
25.8
38.0
1.6
14.2
27.0
45.0
60.0
2.3
20.0
37.0
63.0
--
Segregated Phase
15.5
25.8
38.0
37.0
45.0
60.0
52.0
63.0
--
0.3
0.8
1.2
1.6
3.2
1.6
2.7
3.4
4.0
6.6
2.3
3.9
4.8
5.7
9.3
DC Bus Duct
Derived from ANSI-IEEE C37.23-1987, Tables 3A, 3B, 3C, 3D and paragraph 6.4.2. The table includes a 0.75 multiplier
with fractions rounded down.
Note:
The presence of the column headed "dc" does not imply any requirement for a dc withstand test on ac equipment.
This column is given as a reference only for those using dc tests and represents values believed to be appropriate
and approximately equivalent to the corresponding power frequency withstand test values specified for each class
of bus.
Direct current withstand tests are recommended for flexible bus to avoid the loss of insulation life that may result
from the dielectric heating that occurs with rated frequency withstand testing.
Because of the variable voltage distribution encountered when making dc withstand tests and variances in leakage
currents associated with various insulation systems, the manufacturer should be consulted for recommendations
before applying dc withstand tests to this equipment.
172 MTS-1997
TABLE 10.18
Thermographic Survey
Suggested Actions Based on Temperature Rise
Temperature difference (DT)
based on comparisons
between similar components
under similar loading.
Temperature difference (DT)

based upon comparisons
between component and
ambient air temperatures.
Recommended Action
1C - 3C
0C - 10C
Possible deficiency; warrants

investigation
4C - 15C
11C - 20C
Indicates probable deficiency;

repair as time permits
-- -- --
> 16C
22C - 40C
> 40C
Monitor continuously until

corrective measures can be
accomplished
Major discrepancy; repair
immediately
Temperature specifications vary depending on the exact type of equipment. Even in the same class of
equipment (i.e., cables) there are various temperature ratings. Heating is generally related to the
square of the current; therefore, the load current will have a major impact on T. In the absence of
consensus standards for T, the values in this table will provide reasonable guidelines.
MTS-1997 173
TABLE 10.19
Overpotential Test Voltages for Electrical Apparatus
Other than Inductive Equipment
Nominal
System (Line)
1
Voltage (kV)
Insulation
Class
AC Factory
Test (kV)
Maximum
Field Applied
AC Test (kV)
Maximum
Field Applied
DC Test (kV)
1.2
1.2
10
6.0
8.5
2.4
2.5
15
9.0
12.7
4.8
5.0
19
11.4
16.1
8.3
8.7
26
15.6
22.1
14.4
15.0
34
20.4
28.8
18.0
18.0
40
24.0
33.9
25.0
25.0
50
30.0
42.4
34.5
35.0
70
42.0
59.4
46.0
46.0
95
57.0
80.6
69.0
69.0
140
84.0
118.8
1
Intermediate voltage ratings are placed in the next higher insulation class.
174 MTS-1997
The NETA Affiliate

"Technical Affiliate to the Electrical Testing and Maintenance Industry"
It is the intention of NETA, in establishing the Affiliate classification, to provide interaction
between NETA and those people who require or specify electrical testing. This classification
applies to those individuals who have an interest in the electrical testing industry.
This classification will typically be chosen by engineers, electrical contracting personnel,
project managers, electricians, plant engineers, purchasing agents, and others who wish to
participate and learn about the electrical testing industry.
Benefits of being a NETA Affiliate:
* Access emergency consultation
* Attend Annual Technical Conference at reduced rate
* Attend NETA training seminars at reduced cost
* Receive NETA World technical journal
* Purchase NETA publications at reduced rate
* Serve on Technical Working Committees
* Be an active participant in developing ANSI standards
First Time Affiliates only:
NETA Electrical Acceptance or Maintenance Testing Specifications
included in Affiliate fee.
Send application and Affiliate fee to
Dr. Mary R. Jordan, Executive Director
PO Box 687, 106 Stone Street, Morrison, CO 80465
Phone: 303-697-8441 FAX: 303-697-8431
E-mail: neta@compuserve.com
_________________________________________________________________
NETA Affiliate Application

Name/Title
Firm
Address
City/State/Zip
Phone
* Save on multi-year membership: 1 year $75
Affiliate fee enclosed: Check #
2 years $125
or Visa
3 years $150
Mastercard
Credit Card Number

First time Affiliates: Please send
Expiration Date
Acceptance Specification OR
Maintenance Specification
I hereby agree to abide by the ByLaws of the Association and not to use the NETA logo. I understand my Affiliate status
does not entitle me to claim NETA membership in the performance of electrical testing.
Signature
Date
* Rates current 1997; subject to change.

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Maintenance Testing Specifications

These specifications have been developed

NETA Technical Committee

NETA Standards Review Council

Alan D. Peterson, Chair

Mary R. Jordan, EdD - Executive Director

Did another test that was listed provide similar information?

How commonplace was the test procedure? Is it new technology?

GENERAL SCOPE .................................................................................................................... 1

Circuit Breakers ............................................................................................................. 52

Capacitors and Reactors ............................................................................................. 132

Standard Specification Form

American National Standards Institute - ANSI

American Society for Testing and Materials - ASTM

Association of Edison Illuminating Companies - AEIC

Canadian Standards Association - CSA

Institute of Electrical and Electronic Engineers - IEEE

Insulated Cable Engineers Association - ICEA

InterNational Electrical Testing Association - NETA

National Electrical Manufacturer's Association - NEMA

National Fire Protection Association - NFPA

Occupational Safety and Health Administration - OSHA

Scaffold Industry Association - SIA

State and local codes and ordinances

Underwriters Laboratories, Inc. - UL

3.QUALIFICATIONS OF TESTING FIRM

NETA (InterNational Electrical Testing Association)

NICET, (National Institute for Certification in Engineering Technologies)

Any system, material, or workmanship which is found defective on the basis of

Safety and Precautions

Current Occupational Safety and Health regulations

National Safety Council, Accident Prevention Manual for Industrial

Applicable state and local safety operating procedures

Owner's safety practices

ANSI/NFPA 70E, Electrical Safety Requirements for Employee

OSHA 29 CFR 1910.147. Control of Hazardous Energy Sources

The testing organization shall have a designated safety representative on the

Suitability of Test Equipment

All test equipment shall be in good mechanical and electrical condition.

Split-core current transformers and clamp-on or tong-type ammeters require

Position of the conductor within the core

Clean, tight fit of the core pole faces

Presence of external fields

Accuracy of the current transformer ratio in addition to the accuracy of the

Selection of metering equipment should be based on a knowledge of the

Waveshape and frequency of test equipment output waveforms shall be

Test Instrument Calibration

The accuracy shall be directly traceable to the National Institute of Standards

Instruments shall be calibrated in accordance with the following frequency

Field instruments: Analog, 6 months maximum. Digital, 12 months

Laboratory instruments: 12 months

Leased specialty equipment: 12 months where accuracy is guaranteed by

Dated calibration labels shall be visible on all test equipment.

Up-to-date instrument calibration instructions and procedures shall be

Calibrating standard shall be of higher accuracy than that of the instrument

The test report shall include the following:

Description of equipment tested

Analysis and recommendations

POWER SYSTEM STUDIES