Cable Tray

[SamC]

Does any one know if cables in verticle runs of tray need to be P-clamped or is ty-wrapping still acceptable? Last summer we had a temp electrician working in our plant and he was using P-clamps on all his verticle runs, stating this was a code rule. I never thought anything of this as I was not on this project until recently, when I ty-wrapped some cables on a verticle run and was reminded of this so called rule. I,ve checked my code book and can't find such a rule.

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[electric-ed]

Sam, I don't see any rule that specifies what should be used to fasten the cables.
12-120(2) states that "conductors in vertical raceways shall be supported independently of their terminal connections" ---- "without injury to the conductors or their coverings".

I would say it would depend on the weight of the cables, the height of the vertical part of the run, and the strength of the ty-raps available.

Support spacing is specified in Table 21.

Metal fasteners are usually not permitted for single-conductor cables carrying aver 400 amps to prevent induction heating.

Ed

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