Jeff S
Member
- Location
- St. Louis, MO
2011 NEC 705.12(D)(3) Exception states, "Connection shall be permitted to be made to the load side of ground-fault protection provided that there is ground-fault protection for equipment from all ground-fault current sources. Ground-fault protection devices used with supplies connected to the load-side terminals shall be identified and listed as suitable for backfeeding." I'm referring of course to those services requiring GFP per NEC 230.95 which is pretty much all 480/277VAC 3 ph systems of 1000A or more.
Comments and questions:
What is, "provided that there is ground-fault protection for equipment from all ground-fault current sources." referring to? Apparently not the GFP in an inverter since that's on the DC side. Mike Holt's book on PV basically says that if there's GFP on the main then connect to the supply side. This can be very difficult in a large building. John Wiles has previously stated that he wasn't aware of any GFP breakers that were rated for backfeeding. Was he referring to branch circuit breakers or main breakers? When I called G.E. tech support about their Spectra Series, I was told that the Power Break 1 or 2 frames are all rated for backfeeding. I believe this system uses a Ground Fault Relay. Is that the key- if the GFP is separate from the breaker?
Are all you installers out there connecting to the supply side or is this rule being ignored?
Is it enough to verify that the main breaker doesn't specifically state "line" & "load" terminals to verify that it can be backfed?
Any help clarifying this would be greatly appreciated.
J.S.
Comments and questions:
What is, "provided that there is ground-fault protection for equipment from all ground-fault current sources." referring to? Apparently not the GFP in an inverter since that's on the DC side. Mike Holt's book on PV basically says that if there's GFP on the main then connect to the supply side. This can be very difficult in a large building. John Wiles has previously stated that he wasn't aware of any GFP breakers that were rated for backfeeding. Was he referring to branch circuit breakers or main breakers? When I called G.E. tech support about their Spectra Series, I was told that the Power Break 1 or 2 frames are all rated for backfeeding. I believe this system uses a Ground Fault Relay. Is that the key- if the GFP is separate from the breaker?
Are all you installers out there connecting to the supply side or is this rule being ignored?
Is it enough to verify that the main breaker doesn't specifically state "line" & "load" terminals to verify that it can be backfed?
Any help clarifying this would be greatly appreciated.
J.S.