CableTray NEMA
CableTray NEMA
CableTray NEMA
NEMA STANDARDS
VE 1-1991
REV. NOVEMBER 1993
Scope
This standard covers continuous, complete, metallic systems of ladder,
trough, solid-bottom or channel cable tray intended for, but not limited to,
the support of power, control and signal cables.
Contents
STANDARDS
SECTION 1
SECTION 2
MANUFACTURING STANDARDS
Materials .................................................................................................. 2-4
Finishes..................................................................................................... 2-4
Dimensions ............................................................................................... 2-5
Protection of Cable Installation .................................................................... 2-5
Fittings ...................................................................................................... 2-5
Marking of Trays When Used as Equipment
Grounding Conductors ......................................................................... 2-6
SECTION 3
SECTION 4
TEST STANDARDS
Destruction Load Test .................................................................................. 2-6
Deflection Test ........................................................................................... 2-7
Electrical Continuity of Connections ....................................................... 2-7
SECTION 5
SECTION 6
APPLICATION INFORMATION
Deflection .................................................................................................. 2-8
Concentrated Static Load ............................................................................ 2-8
Warning! Walkways .................................................................................. 2-8
Fittings ...................................................................................................... 2-8
Supports ................................................................................................... 2-8
Support Locations ...................................................................................... 2-8
Protection of Cable Insulation ..................................................................... 2-9
Thermal Contraction and Expansion ............................................................ 2-9
Cable Insulation ........................................................................................ 2-9
Support Locations for Fittings ............................................................... 2-10
FIGURES 6-1
THROUGH 6-8
FIGURE 6-9
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NEMA Standards
SECTION 1
Referenced Standards & Definitions
1.2 DEFINITIONS
Metallic Cable Tray System An assembly of cable tray
straight sections, fittings, and accessories that forms a rigid
structural system to support cables.
2-3
STANDARDS
Channel Cable Tray A prefabricated metal structure
consisting of a one-piece ventilated bottom or solid-bottom channel
section, or both, not exceeding 6" (152mm) in width.
SECTION 2
Manufacturing Standards
2.1 MATERIALS
Cable tray systems shall be made of either corrosion-resistant metal
or metal with a corrosion-resistant finish.
NEMA Standards
edges and heat-affected zone of welding are subject to
superficial oxidation. These areas are then protected through
electrolytic action of the adjacent zinc surfaces. The coating is
smooth, ductile, and adherent.
2.2 FINISHES
2.2.1 Carbon steel used for cable trays shall be protected against
corrosion by one of the following processes:
A. Hot-dip mill galvanized in accordance with ASTM Publication
No. A525 G90 Coating.*
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NEMA Standards
2.3 DIMENSIONS
2.3.1 General
Plus or minus values stated reflect the range of nominal dimensions
in cable tray designs and are not intended to represent manufacturing tolerances.
2.5 FITTINGS
The design and construction of fittings shall be based on the
assumption that they will be supported in accordance with the
recommendations given in 6.6 for support locations.
2-5
NEMA Standards
STANDARDS
SECTION 4
Test Standards
SECTION 3
Performance Standards & Load/Span
Class Designations
4.1.4 Supports
Load
(kg/m)
Support
Feet
Span
(m)
Designation
Per 3.1
(74.4)
(111.6)
(148.8)
(74.4)
(111.6)
(148.8)
(74.4)
(111.6)
(148.8)
(74.4)
(111.6)
(148.8)
8
8
8
12
12
12
16
16
16
20
20
20
(2.44)
(2.44)
(2.44)
(3.66)
(3.66)
(3.66)
(4.87)
(4.87)
(4.87)
(6.09)
(6.09)
(6.09)
8A
8B
8C
12A
12B
12C
16A
16B
16C
20A
20B
20C
NOTE 1- The above working loads are for cable only; when considering applications requiring concentrated static load, see 6.2.
NOTE 2 - These designations do not apply to channel tray, and the
manufacturer should be consulted.
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NEMA Standards
4.1.6 Loading
Each specimen shall consist of two 24" (610mm) lengths of side rail
plus mechanical connecting means.
SECTION 5
specifications & Drawings
5.1 DATA TO APPEAR IN SPECIFICATIONS
The following statement and minimum data, when applicable,
should appear in all cable tray specifications:
1. Cable tray shall be manufactured and installed in
accordance with NEMA Standard VE 1-1991
2. Load/span class designation (see Section 3)
3. Type (see Section 1.2)
4. Material (see Section 2.1)
5. Finish (see Section 2.2)
6. Rung Spacing (see Section 2.3)
7. Inside depth (see Section 2.3)
8. Width (see Section 2.3)
9. Fitting Radius (see Section 2.3)
10. Accessories (see Section 1.2).
2-7
NEMA Standards
STANDARDS
SECTION 6
Application Information
6.1 DEFLECTION
Under normal applications deflection limitations should not be
included in design criteria for cable trays. However, if unusual or
special conditions exist, the manufacturer should be consulted.
Limitations of deflection for aesthetic purpose only can result in an
over-designed tray system.
6.5 SUPPORTS
Supports for cable trays should provide a strength and working
load capacity sufficient to meet the load requirement of the cable
tray systems.
1. Horizontal and vertical tray supports should provide an
adequate bearing surface for the tray and should have
provisions for holddown clamps or fasteners.
2. In addition, vertical tray supports should provide secured
means for fastening cable trays to supports.
6.4 FITTINGS
Changes in direction should be mechanically continuous and
accomplished by use of fittings having dimensions in accordance
with 2.3.
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NEMA Standards
Table 6-1
MAXIMUM SPACING BETWEEN EXPANSION JOINTS THAT PROVIDE
FOR 1" (25.4mm) MOVEMENT
Temp. Differential
F
(C)
Feet
(m)
25
50
75
100
125
150
175
512
256
171
128
102
85
73
(156)
(78.0)
(52.1)
(39.0)
(31.1)
(25.9)
(22.2)
(-4)
(10)
(24)
(38)
(51)
(65)
(79)
Steel
Aluminum
Feet
(m)
260
130
87
65
52
43
37
(79.2)
(39.6)
(26.5)
(19.8)
(15.8)
(13.1)
(11.3)
2-9
STANDARDS
2'0" Max.
[610 mm]
.
ax ]
M m
"
0 m
2' 10
[6
2'0" Max.
[610 mm]
2'0" Max.
[610 mm]
Figure 6-5
STRAIGHT REDUCER
Figure 6-1
HORIZONTAL ELBOWS
2'0" Max.
[610 mm]
2'0" Max.
[610 mm]
3 R
2'0" Max.
[610 mm]
2 L
2'0" Max.
[610 mm]
Figure 6-6
OFFSET REDUCER
Figure 6-2
HORIZONTAL TEE
3 R
2'0" Max.
[610 mm]
= 30, 45, 60, 90
2'0" Max.
[610 mm]
2'0" Max.
[610 mm]
Figure 6-3
HORIZONTAL CROSS
Figure 6-7
VERTICAL ELBOWS
22.5
45
.
ax ]
M m
"
0 m
2' 10
[6
2'0" Max.
[610 mm]
2'0" Max.
[610 mm]
2'0" Max.
[610 mm]
2'0" Max.
[610 mm]
2'0" Max.
[610 mm]
Figure 6-4
HORIZONTAL WYE
2- 1 0
Figure 6-8
VERTICAL TEE
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NEMA Standards
GAP SETTINGS
MIN. TEMP.
MAX. TEMP.
130
50
40
30
20
110
90
10
50
30
10
10
20
TE
70
PE
RA
TU
RE
SL
O
PE
10
30
30
40
C
F
0
1 8
1 4
(0.0)
(3.2)
(6.3)
3 8
1 2
5 8
3 4
7 8
Figure 6-9
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STANDARDS
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