Table 392.3(A) Wiring Methods
392.1 Scope. This article covers cable tray systems, in cluding ladder, ventilated trough, ventilated channel, solid bottom, and other similar structures.
FPN: For further information on cable trays, see ANSI/NEMA-VE 1-1998, Metal Cable Tray Systems; NEMA-VE 2-1996, Metal Cable Tray Installation Guide- lines; and NEMA-FG-1998, Nonmetallic Cable Tray Systems.
392.2 Definition.
Cable Tray System. A unit or assembly of units or sections and associated fittings forming a structural system used to securely fasten or support cables and raceways.
392.3 Uses Permitted. Cable tray shall be permitted to be used as a support system for service conductors, feeders, branch circuits, communications circuits, control circuits, and signaling circuits. Cable tray installations shall not be limited to industrial establishments. Where exposed to direct rays of the sun, insulated conductors and jacketed cables shall be identified as being sunlight resistant. Cable trays and their associated fittings shall be identified for the intended use.
(A) Wiring Methods. The wiring methods in Table
392.3(A) shall be permitted to be installed in cable tray
systems under the conditions described in their
respective articles and sections.
Wiring Method Article
Armored cable 320
CATV cables 820
CATV raceways 820
Class 2 and Class 3 cables 725
Communications cables 800
Communications raceways 800
Electrical metallic tubing 358
Electrical nonmetallic tubing 362
Fire alarm cables 760
Flexible metal conduit 348
Flexible metallic tubing 360
Instrumentation tray cable 727
Intermediate metal conduit 342
Liquidtight flexible metal conduit 350
Liquidtight flexible nonmetallic conduit 356
Metal-clad cable 330
Mineral-insulated, metal-sheathed cable 332
Multiconductor service-entrance cable 338
Multiconductor underground feeder and 340
branch-circuit cable
Network-powered broadband communications 830
cables
Nonmetallic-sheathed cable 334
Non-power-limited fire alarm cable 760
Optical fiber cables 770
Optical fiber raceways 770
Other factory-assembled, multiconductor control, signal, or power cables that are specifically approved for installation in cable trays
(B) In Industrial Establishments. The wiring methods in Table 392.3(A) shall be permitted to be used in any industrial establishment under the conditions described in their respective articles. In industrial establishments only, where conditions of maintenance and supervision ensure that only qualified persons service the installed cable tray system, any of the cables in 392.3(B)(1) and (B)(2) shall be permitted to be installed in ladder, ventilated trough, solid bottom, or ventilated channel cable trays.
(1) Single Conductors. Single-conductor cables shall be permitted to be installed in accordance with (B)(1)(a) through (B)(1)(c).
(a) Single-conductor cable shall be 1/0 AWG or larger and shall be of a type listed and marked on the surface for use in cable trays. Where 1/0 AWG through 4/0
AWG single-conductor cables are installed in ladder cable tray, the maximum allowable rung spacing for the ladder cable tray shall be 225 mm (9 in.).
(b) Welding cables shall comply with the provisions of Article 630, Part IV.
(c) Single conductors used as equipment grounding conductors shall be insulated, covered, or bare, and they shall be 4 AWG or larger.
(2) Medium Voltage. Single- and multiconductor medium voltage cables shall be Type MV cable. Single conductors shall be installed in accordance with
392.3(B)(1).
(C) Equipment Grounding Conductors. Metallic cable