NEC 2011 70512.(D)(3)
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texie
Senior Member
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- Fort Collins, Colorado
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- Electrician, Contractor, Inspector
It was determined that 705.12 (3) was redundant and removed since this is covered in 705.32.
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- Placerville, CA, USA
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- Retired PV System Designer
That is not just a regulatory provision, it is a practical provision.
If the PV does not also incorporate its own GFP (or even if it does) and it faults, then you could have unbalanced currents in the main breaker causing a main trip without any faults anywhere in the rest of the system.
Where the GFP is integral with the CB, yes. If it is a separate GFP relay, you can connect load-side between MCB and GFP... but physical means to do so will likely be restrictive.
GoldDigger,
I assume you are talking about a fault at the PV? Can you explanin how it will create unbalanced currents in the man circuit breaker? I guess I couldn't quite get how the current will flow if there is a fault.
What if there is a second level (or even thrid) GFP down stream of the main? We could put a sub-panel with GFP for the PV system interconnction.
- Location
- Placerville, CA, USA
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- Retired PV System Designer
If there is a ground fault in the inverter which does not cause it to be disconnected, the "missing" neutral current cannot come from anywhere except the ground-neutral bond at the service, which will trip the GFP at the main.
If there is GFP closer to the GTI then it may or may not trip first. Coordination of GFP can be difficult.
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If there is GFP closer to the GTI then it may or may not trip first. Coordination of GFP can be difficult.
Sent from my XT1080 using Tapatalk
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