THHN Conductors and Cable Trays

I routinely do. NEC will guide you as to capacity.

Thank you.

Table 392.3(A) covers types of cables and conduits that can be run in trays in most locations. This table mostly lists multi-conductor cables and communications cables. (No THHN.)

Article 392.3(B)(1)(a) of the NEC covers the use single-conductors in cable trays In Industrial Establishments:

(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.).

Article 392.11(B) covers ampacities of single-conductor cables in cable trays. Article 392.11(C) deals with mixing multi- and single-conductor cables in a cable tray.

I'm in Latin America. We use NEC like excellent guide. I'm using NEC 1999. I'll get NEC 2008. Thank you very much.

Glad to offer some advice. Welcome to CR4

Thank you for valuable attendance.

You can't install THHN wires in cable tray or exposed, in other words exposed to mechancial injury. you can lay it in a closed containment like conduits or cable trunkings.

I read specifications THHN 4/0 Phelps Dodge is for cable tray (CT) use. I suppose with cable tray installed out of mechanical injury.

NO...........Not in cable tray single conductor THHN, it needs to be run in a seperate tray as a power conductor in a multiconductor cable , or shields put in as the same as keeping them seperated from the HV(480) and 24vdc plc or DCS cables . I have seen some plants that have done this (due to the older multiconductor cable shorting out as a temporary (bandaid fix) to keep the process going, after hours of determing which conductor was bad in the cable. It is certainly not an engineering pratice by any means. Conduit and THHN is the only way to go. Always pull extra when you do pull it, and think of future needs. As far as I am concerned thats should be in any country.

According NEC 2005 Section 392.11(B) a group of single conductors installed in triangle or square config. can be used. But your observation and recommendation are very important./p]