Prospex

[Prospex]

When the requirements/conditions of 250.32(B)(2) are present, are a separate grounding electrode with a grounding electrode conductor bonded to the panelboard in the separate building required in order to provide a separate path to earth ground?

My understanding is that, even though the grounded neutral conductor provides a path back to the main panel or S.E.S. (service entrance section) grounding electrode, that is not the grounded neutral conductor?s primary job?it?s the grounding conductor?s job.

Since there's neither a grounding conductor nor any other electrically continuous systems that bond the main panel to the panel in the separate building, the panel in the separate building can, in effect, be considered a separate S.E.S. Therefore, all applicable bonding requirements apply to this panel.

 

[bphgravity]

I think you understand the fundemental idea, except the actual grounding or earthing of the system plays no role in the operational aspects of the premise wiring both under normal and fault conditions. 250.32(B)(1) provides an insualted path for normally operating current to flow back to the source and an effective fualt path for the return ground fault current. The 250.32(B)(2) has the grounded (neutral) perform both functions.

In either case, a grounding electrode system at the separate building or structure is required. The NEC requirement for grounding of the equipment at the separate building or structure is primarily for lightning protection.

 

[suemarkp]

If by bonding you mean using article 230 raceway bonding rules for that panel, I don't think that applies. Yes, you're wiring this like a service, but it is not a service per NEC 230 if there is any breaker in that line to the second building.

Neutral/ground bonding jumper yes. Bonding locknuts or bushings, not required as long as this is a feeder from the other building.

 

[iwire]

Bonding locknuts or bushings, not required as long as this is a feeder from the other building.

That would be dependent on voltage and the equipment used. 250.97

Prospex be quick with your application of 250.32(B) it is likely that it will not exist in the 2008 NEC.