Main service disconnect at exterior pole

jfrederick · October 18, 2016, 5:56pm

I’ve asked this before, but I couldn’t find it anywhere here. Regardless…
When a main service disconnect/panel is at an exterior pole(which I see a lot), the remote distribution panels, fed from this panel, inside the house. exterior buildings. etc. would be considered “detached buildings,” correct? The house today was built in 2004 and all feeds from the main service disconnect at the exterior pole were 3-wire. So 3 wire feeds would be o.k., as long as there are no other metallic connections from the pole?

Hope this makes some sense - lol.
TIA.

rmeier2 · October 18, 2016, 7:55pm

For 2004 you would be correct, the change came to eliminate this exception in the 2008 NEC. This is some explanatory material from 250.32(A) in the 2005 NECH:

Where a building or structure is supplied by a feeder, 250.32(A) requires that a grounding electrode system be established at each building or structure supplied, unless one already exists. The equipment grounding bus must be bonded to the grounding electrode system, and the disconnecting means enclosure, building steel, and interior metal water piping are also required to be bonded to the grounding electrode
system. All exposed non–current-carrying metal parts of electrical equipment are required to be grounded through equipment grounding conductor connections to the equipment grounding bus at the building disconnecting means. The connection of the grounded (neutral) conductor to the grounding electrode system, as shown in Exhibit 250.16, is permitted only where it can be ensured that such a connection does not
establish a parallel circuit path for normal neutral current on equipment grounding conductors, metal shields of cables not intended to be used as a current-carrying conductor, metal piping systems, or other metal structures that are continuous between buildings.