ECN Forum Forums Code Related Discussion NEC & other Code issues What do you guys think?

Can we equate this large bored hole to a cable tray? Are there any rules on installing cables in cable tray? Would they then apply?
I see in 392.11(A) that multiple cables are allowed to be installed in open cable trays without derating of the conductors, so long as the individual cables do not require derating due to more than three current carrying conductors in one cable.
Using these rules for bored holes in basements is a stretch, I know. But maybe somebody's proposal can borrow some of the verbiage.

I'll bet if bundling were required the joists wouldn't satisfy bundling.

Can you Have it both ways?

Can any one of the people who insist that multiple runs of romex thru drilled holes in DWELLINGS needs to be derated show us any event that has actually contributed to a single house fire, unless a branch circuit itself was improperly overloaded?

I don't beleive that code requires derating because multiple cables pass through a joist or joists.

I would ask an inspector, or anybody else, to show me in code.

By Gfretwell:

"I really don't start thinking about derating unless I see a very pretty bundle with carefully aligned cable bundles. The cables in the middle are cooking. If you fan them out between holes they can breathe."

I wish I could claim to be the guy who came to this realization but I'm only repeating something that I heard from smarter people.

If you're talking about a residence. And you have only 12 and 14 AWG NM (no ranges heaters and such). Think about the load you're likely to find throughout the entire building at any one time. Even if you bundle all those circuits, I don't think in the vast majority of cases you'll have enough current to cause enough heating that you would need to derate.

Edit: fixed spelling

[This message has been edited by Physis (edited 12-29-2004).]