ANSI C80.

3-2020

Approved as an American National Standard

ANSI Approval Date: December 29, 2020

American National Standard for

Electrical Metallic Tubing—Steel (EMT-S)

Secretariat:

National Electrical Manufacturers Association

Approved: December 29, 2020

American National Standards Institute, Inc.

 NOTICE AND DISCLAIMER

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© 2021 National Electrical Manufacturers Assocation

 ANSI C80.3-2020
Page i

AMERICAN Approval of an American National Standard requires verification by

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NATIONAL criteria for approval have been met by the Standards developer.

STANDARD Consensus is established when, in the judgment of the ANSI Board of

Standards Review, substantial agreement has been reached by directly
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Published by

National Electrical Manufacturers Association

1300 North 17th Street, Rosslyn, VA 22209
www.nema.org

 2021 National Electrical Manufacturers Association. All rights reserved including translation into other
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of Literary and Artistic Works, and the International and Pan American Copyright Conventions.

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Printed in the United States of America

ANSI C80.3-2020
Page ii

Foreword (This foreword is not part of American National Standard C80.3-2021)

This Standard was developed by the Accredited Standards Committee on Raceways for Electrical Wiring
Systems, C80. The objective of the committee is to produce a comprehensive specification that will
establish uniform dimensions and Standard construction requirements for Electrical Rigid Steel Conduit,
Steel Electrical Metallic Tubing, Electrical Intermediate Metal Conduit, and Electrical Aluminum Rigid
Conduit raceway products and their associated components.

This Standard was originally approved in 1950 and revised in 1953, 1959, 1963, 1966, 1977, 1983, 1990,
1994, 2004, 2005, and 2015.

Suggestions for improvement of this Standard are welcome. They should be sent to:

NEMA Technical Operations Department

National Electrical Manufacturers Association
1300 North 17th Street, Suite 900
Rosslyn, VA 22209

This Standard was processed and approved for submittal to ANSI by the Accredited Standards Committee
(ASC C80), Raceways for Electrical Wiring Systems. Committee approval of the Standard does not
necessarily imply that all committee Members voted for its approval. At the time it approved this Standard,
the C80 Committee had the following Members:

J. Burris, Chairman
K. Shen, Secretary
Organization Represented: Name of Representative:
ABB Inc. D. Kendall
Atkore International R. Horner
Atkore International E. Iverson
Emerson Automation Solutions S. Blais
IBEW P. Hickman
International Association of Electrical Inspectors D. Humphrey
National Electrical Contractors Association M. Johnston
Nucor J. Broussard
SAPA Extrusions North America H. Harper
STI J. Andre
UL LLC D. Gerstetter
Western Tube (Division of Zekelman Industries) A. Nunez
Wheatland Tube Company J. Burris

The following Members of the NEMA Steel Conduit & Electrical Metallic Tubing - Codes/Communications/
Technical Committee worked on this Standard prior to its publication:

J. Burris, Co-Chair
R. Horner, Co-Chair
K. Shen, Secretary
Organization Represented: Name of Representative:
ABB Inc. D. Kendall
Atkore International B. Deacy
Atkore International R. Horner
Atkore International E. Iverson
Consultant (STI) P. Dobrowsky
Nucor J. Broussard
Nucor N. Fraser

© 2021 National Electrical Manufacturers Assocation

 ANSI C80.3-2020
Page iii

Nucor G. Fuentes
Nucor C. Wood
Robroy Industries, Inc. S. Voelzke
Steel Tube Institute of North America B. Sullivan
STI J. Andre
Western Tube (Division of Zekelman Industries) A. Nunez
Wheatland Tube Company J. Burris
Wheatland Tube Company G. Maurer

© 2021 National Electrical Manufacturers Association

ANSI C80.3-2020
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© 2021 National Electrical Manufacturers Assocation

 ANSI C80.3-2020
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CONTENTS

1 Scope ................................................................................................................................................... 1
2 Normative References ....................................................................................................................... 1
3 Definitions ........................................................................................................................................... 1
4 Units of Measurement ........................................................................................................................ 2
5 General Requirements ....................................................................................................................... 2
5.1 Circular cross section ................................................................................................................... 2
5.2 Wall thickness ............................................................................................................................... 2
5.3 Interior surface .............................................................................................................................. 2
5.4 Welding ......................................................................................................................................... 2
5.5 Cleaning ........................................................................................................................................ 2
5.6 Protective coating for corrosion resistance ................................................................................... 2
5.7 Surface treatment ......................................................................................................................... 2
6 Detailed Requirements ...................................................................................................................... 2
6.1 Exterior coating ............................................................................................................................. 2
6.1.1 Zinc coating .......................................................................................................................... 3
6.1.2 Alternate corrosion resistant coating (ACRC) ...................................................................... 3
6.2 Interior coating .............................................................................................................................. 3
6.3 Chamfering ................................................................................................................................... 3
6.4 Identification .................................................................................................................................. 3
6.5 Dimensions ................................................................................................................................... 3
6.6 Elbows .......................................................................................................................................... 3
7 Test Procedures ................................................................................................................................. 3
7.1 Bending properties ........................................................................................................................ 3
7.1.1 Ductility of steel..................................................................................................................... 3
7.1.2 Ductility of coatings at ambient temperature ........................................................................ 3
7.2 Thickness of zinc coating .............................................................................................................. 4
7.3 Alternate corrosion resistant coatings (ACRC) ............................................................................. 4
7.4 Performance requirement of organic coating for use on interior surface ..................................... 4
8 Examination of Product ..................................................................................................................... 4
8.1 Place of inspection ........................................................................................................................ 4
8.2 Visual inspection of tubing ............................................................................................................ 4
8.3 Visual inspection of elbows ........................................................................................................... 4
8.4 Retest ............................................................................................................................................ 4
9 Markings .............................................................................................................................................. 4
9.1 General ......................................................................................................................................... 4
9.2 Nonmetallic alternate corrosion resistant coating temperature marking ...................................... 5
9.3 Supplementary coating marking ................................................................................................... 5

© 2021 National Electrical Manufacturers Association

ANSI C80.3-2020
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TABLES
Table 1 Dimensions and weights for EMT-S................................................................................................. 6
Table 2 Minimum dimensions for 90-degree elbows .................................................................................... 7

© 2021 National Electrical Manufacturers Assocation

 ANSI C80.3-2020
Page 1

1 Scope
This Standard covers the requirements for steel electrical metallic tubing for use as a raceway for wires or
cables of an electrical system. Finished tubing is typically furnished in Standard 10-ft (3.05-m) lengths.
The production of lengths shorter or longer than the Standard length shall be allowed. EMT is protected
on the exterior surface with a metallic zinc coating or alternate corrosion protection coating (see UL 797
for alternate corrosion protection coating requirements) and on the interior surface with zinc or organic
coating.

This Standard also covers electrical metallic tubing elbows.

Properly assembled systems of EMT-S, manufactured in accordance with this Standard, and other
identified fitting provide for the electrical continuity required of an equipment grounding conductor.

© 2021 National Electrical Manufacturers Association