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Cooper B-Line, Inc Cable Tray Manual
392.9. Number of Multiconductor Cables,
Rated 2000 Volts, Nominal, or Less, in
Cable Trays. (C) Solid Bottom Cable
Trays Containing Any Mixture. (2) Cables
Smaller Than 4/0
The procedure used in selecting a cable tray width
for the type of cable covered in this section is similar
to that shown on Appendix Sheet 4 page 48. The
maximum allowable cable fill area is in Column 3 of
Table 392.9.
392.9. Number of Multiconductor Cables,
Rated 2000 Volts, Nominal, or Less, in
Cable Trays. (C) Solid Bottom Cable
Trays Containing any Mixture. (3) 4/0 or
Larger Cables Installed With Cables
Smaller Than 4/0
No. 4/0 and larger cables must have a dedicated
zone in the tray in order to be installed in one layer.
Therefore the cable tray needs to be divided into
two zones (a barrier or divider is not required but
one can be used if desired).
The formula for this type of installation is shown
in Column 4 of Table 392.9. This formula is a trial
and error method of selecting a cable tray of the
proper width. A direct method for determining the
cable tray width is available by figuring the cable tray
widths that are required for each of the cable
combinations and then adding these widths together
to select the proper cable tray width. [Sd (sum of the
diameters of the No. 4/0 and larger cables) x
(1.11)] + [(Sum of Total Cross-Sectional Area of all
Cables No. 3/0 and Smaller) x (6 inches/5.5
square inches) = The Minimum Width of Cable Tray
Required. The procedure used in selecting a cable
tray width for the type of cables covered in this
section is similar to that shown on Appendix Sheet
5 page 49.
392.9. Number of Multiconductor Cables,
Rated 2000 Volts, Nominal, or Less, in
Cable Trays. (D) Solid Bottom Cable Tray
Multiconductor Control and/or Signal
Cables Only.
This is the same procedure as for ladder and
ventilated trough cable trays except that the
allowable fill has been reduced from 50 percent to
40 percent. The procedure used in selecting a cable
tray width for the type of cable covered in this
section is similar to that shown on Appendix Sheet
6 page 50.
[Example 392.9(B)]
392.9. Number of Multiconductor Cables,
Rated 2000 Volts, Nominal, or Less in
Cable Trays. (E) Ventilated Channel Cable
Trays.
392.9(E)(1)
Where only one multiconductor cable is installed
in a ventilated channel cable tray.
392.9(E)(2)
The fill areas for combinations of multiconductor
cables of any type installed in ventilated channel
cable tray.
392.9. Number of Multiconductor Cables,
Rated 2000 Volts, Nominal, or Less in
Cable Trays. (F) Solid Channel Cable
Trays.
392.9(F)(1)
Where only one multiconductor cable is installed
in a solid channel cable tray.
Ventilated Channel Maximum Allowable
Cable Tray Size Fill Area
3 Inch Wide 1.3 Square Inches
4 Inch Wide 2.5 Square Inches
6 Inch Wide 3.8 Square Inches
Ventilated Channel Maximum Cross-Sectional
Cable Tray Size Area of the Cable
3 Inch Wide 2.3 Square Inches
4 Inch Wide 4.5 Square Inches
6 Inch Wide 7.0 Square Inches
Solid Channel Maximum Cross-Sectional
Cable Tray Size Area of the Cable
2 Inch Wide 1.3 Square Inches
3 Inch Wide 2.0 Square Inches
4 Inch Wide 3.7 Square Inches
6 Inch Wide 5.5 Square Inches