guys, I need help with this ons... given a large multifamliy dwelling unit has (2) services, The building has a (2)hour rated party wall halfway the building, this is not a true fire wall, therefore this is considered to be one building. my question is to comply with 250.58, to have a single grounding system, Can the bonding jumper that connects service #1 to service #2 be routed through the attic of the the building ? thanks, mj

Mj, there is nothing prohibiting running through the attic as far as the NEC is concerned, there could possibly be a local code though.

Just be sure to use a proper "through penetration assembly" (fire cauking) when going through the rated wall.

Roger

thanks Roger, I have a contractor that do not understand the purpose of 250.58 since the slap in already in, I was going to suggest routing the bonding jumper through the attic to create a single grounding electrode system.

need help guys.... any more details to support sec# 250.58, commom gronding electrode where there are multiple services on one building ? I have a board meeting soon, and I need to prove my case for requiring the bonding of electrodes for all services. thanks, mj

does any kwows how long this requirment has been required in the nec .... "common gronding electrode,Sec # 250.58 " I had one inspector stated that it was not required in the 1990 nec.