The cold water ground thread brought up an old issue. An inspector asked me to insulate a conduit from HVAC duct. I'm assuming the idea is that a ground fault will be carried by the conduit, not the duct. I'm not quite following the reality that conduit is running to the furnace, which is multiple screwed to the duct. Since it's bonded there, what's the purpose of insulating it anywhere?
I think he meant "separate." While not mentioned (afaik) in the NEC, I was taught that my conduit was not allowed to touch other utilities; where contact was unavoidable, a thick pad was used to separate the two.
I was taught that this was to prevent wear caused by isloation; we could rub holes in out pipes, but not anyone elses'.
#99896 - 09/23/0605:44 PMRe: Insulating Conduit from HVAC Duct