250.24(B) - Grounded Conductors Beyond Service Equipment

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ptrombley

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I think I understand 250.24(B), but I have a situation where a feeder is run to a sub-panel (from the main service) and no grounded (neutral) conductor was run because the load is 240-volt and does not require a neutral. The sub-panel, however has extra breaker spaces in it. What does the NEC say about this? Does the grounded conductor need to be extended to this sub-panel for future 120-volt circuits? Would it make a difference if it were just a 2-pole disconnect (without extra breaker spaces)? Thanks for your help - Paul.
 
What does the NEC say about this? Does the grounded conductor need to be extended to this sub-panel for future 120-volt circuits? Would it make a difference if it were just a 2-pole disconnect (without extra breaker spaces)?

The NEC doesn't require a grounded conductor to be brought to a sub-panel for future use. This would be a design issue not a code issue.

250.24(C) requires a grounded conductor to be brought to, and bonded to, a service to provide a effective ground-fault current path from the service to the utility source. The sub-panel is required to have an equipment grounding conductor of the type listed in 250.118 to provide the effective ground-fault current path for the sub-panel.

Hope this helps,

Chris
 
A feeder does not (as far as the NEC is concerned) have to include a Grounded conductor if the load(s) does not require one, an EGC would be the fault clearing path.

If a load in the future requires a grounded conductor it would have to be addressed then.

Roger
 
The grounded conductor on a grounded system is only required at the first disconnect and any other points that require the grounded conductor.

"Does the grounded conductor need to be extended to this sub-panel for future 120-volt circuits?"

It's not required for future circuits.
 
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