Actually, it is permitted by the NEC (depending on the insulation type). But
you're right about being able to pull the wires.
Doug Miller (alphageek at milmac dot com)
How come we choose from just two people to run for president and 50 for Miss America?
You know not that of which you speak.
U.S. National Electrical Code allows *SIX* #10 wires in 1/2" conduit, with
appropriate insulation -- e.g. THHN.
And it _can_ be done, over short distances, with a limited number of bends .
I _know_, because I've _got_ a circa 8' section, that is so loaded.
It was a *real* b*tch to pull the wiring, particularly past the 3rd bend. :)
Done under 'permit' from the city, and the City electrical inspector _has_
signed off on it.
Derating in this application is not important. You would derate to 80% but THHN
#10 cu is good for 40a and 240.4(D) limits you to 30a so you still have a
safety factor, even with the derate.
You only have to derate based on current carrying conductors and you don't need
to derate the conductors that only carry the unbalanced current of a multiwire
circuit so it usually takes a lot of wire in a pipe before a THHN run is
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