kingelectric
Member
3-480v 30amp rooftop units with 3 # 10s and one common # 10 ground wire in a 1'' conduit ,the inspector said we could not do this. Any code violation here??
the inspector said we could not do this
correct.3-3phase circuits with 3 # 10s thhn to each and 1-# 10 egc in a 1'' emt conduit, inspector said to many current carrying conductor and need seperate ground wire to each.
sounds as if you have encounter an inspector who may not know the NEC.
If you are using THHN, the derated value for the 9 wires (assuming no ambient problem) would be 28 amps.
With a 19.5 MCA, you would actually be legal with #12s ( #12 @ 90?C =20 x .7 = 21) (based on '08 ratings)