I find nothing in NEC regarding derating THHN that is embedded in ceiling foam insulation. Any ideas whether #12 should be derated? Thanks.
THHN conductors are required to be installed within a raceway or be part of a cable assembly, so the conductor should never be in direct contact with the insulation. Some of the cable Articles like 334 and 338 have specific requirements for insulation contact, in addition the adjustment factors in 310.15 would also apply.
Jerry, what is the Chapter 3 wiring method?
Retrieving data ...