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neutrals and derating?

15K views 7 replies 4 participants last post by  randerson1983 
#1 ·
when derating wires due to conduit fill, there is exceptions talking about the neutral not needing to be counted as a "current carrying conductor" if it is carrying only the unbalanced load of a multiwire circut.... so when do you not have to count the neutral as a current carrying conductor?


thanks for all the help you can give me!
 
#5 ·
Derating and conduit fill are totally different items.

Derating is to reduce the amount of heat that can affect the insulation. Fill is how many little circles can be put in to a large circle.
LoL, Do ya hasta bust everyone's balls 480?

.... so when do you not have to count the neutral as a current carrying conductor?

My opinion is that you always count a neutral as a current carrying conductor. If you believe that you have a valid exception then follow it. If you are not sure, don't.

310.15(B)(4) describes the only case I know where you are allowed to not count the neutral conductor as a current carrying conductor.

Personally, I would only use that if I had to. Do understand I prefer a little overkill anytime I can afford it.
 
#3 ·
when derating wires due to conduit fill, there is exceptions talking about the neutral not needing to be counted as a "current carrying conductor" if it is carrying only the unbalanced load of a multiwire circut.... so when do you not have to count the neutral as a current carrying conductor?


thanks for all the help you can give me!

Easy, when it's not a current carrying conductor. :blink:


You answered your own question. When the neutral is neutral, a common to two ungrounded conductors, it does not need to be counted as a CCC.
 
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