I have a 2500 amp service on a Nursing Home.We had one of the underground service feeders short out and we need to replace the (4) 500 mcm THW cables with new wire.My question is,does the new wire have to be THW or can i use THWN.The AHJ says we need to replace the wire in all 7 conduits because they need to be the same type of wire.Can someone point this out to me in the code.I agree they should be the same size,but i'm upgrading the insulation only from THW to THWN.
Any help will be greatly appreciated.
Thanks,Dennis
Any help will be greatly appreciated.
Thanks,Dennis