Derating current carrying conductors.

[Phil Corso]

Did Robert mean mean 480Y/277? If so, what about the neutral? And derating for all conductors are iin the same raceway?

Phil Corso​

 

[Phil Corso]

Sorry, my post was intended for the another Topic!

Phil Corso

 

[kwired]

Some, yes. Enough that derating would not be necessary, who knows?

If you put a condulet every 24" without branching off, would you dissipate more heat? ...or less?

I think that the argument here is that the NEC wording does not support the practical applicaiton. In your example the conduit bodies would do little to disapate heat.

That is my point.

I agree with both of you, but at same time putting a box every 2 feet really is not a violation as worded. Would also cost more than using larger conductors in most cases so the problem kind of takes care of itself.

 

[Smart $]

I agree with both of you, but at same time putting a box every 2 feet really is not a violation as worded. Would also cost more than using larger conductors in most cases so the problem kind of takes care of itself.

Well then, let's use a more practical scenario...

Total conduit run length less than 4', using two "nipples", both less than 2', with one condulet joining them. Not required to derate... but should we?

 

[fmtjfw]

Word smithing does not trump physics.:happyno: If you can lawyer up a thesis as to why your scheme "meets the letter of the code", it still may overheat.:happysad:

 

[don_resqcapt19]

Word smithing does not trump physics.:happyno: If you can lawyer up a thesis as to why your scheme "meets the letter of the code", it still may overheat.:happysad:

We don't have to obey the laws of physics....only the laws of the NEC

 

[kwired]

Word smithing does not trump physics.:happyno: If you can lawyer up a thesis as to why your scheme "meets the letter of the code", it still may overheat.:happysad:

Absolutely correct.

We don't have to obey the laws of physics....only the laws of the NEC

Also correct.

Is a change needed in NEC to keep us from running all these short runs with just pull boxes or conduit bodies to make the deration issue go away? I think not. Cost alone is going to keep that from happening, except for the DIY that wants to use a bunch of used or close out items just because they were cheap, but chances are they are not paying attention to deration requirements anyway.