grounding electrode/ system in buildings supplied by feeders or BCs

[Electron_Sam78]

250.32 seems to suggest that grandfathering is not acceptable - if there is no GE or GES in place at an existing feeder/BC supplied building. If you come across such a building then you must install one?

 

[Buck Parrish]

It makes sense if you are working on the service.

 

[SG-1]

250.32(A) Exception A

A grounding electrode shall not be required where only a single branch circuit...

 

[Electron_Sam78]

That's not the scenario here

250.32(A) Exception A

A grounding electrode shall not be required where only a single branch circuit...

 

[Smart $]

250.32(A) Exception A

A grounding electrode shall not be required where only a single branch circuit...

IMO, that's an odd exception. '08 code requires an EGC with a feeder or branch circuit supplying another building or structure and also does not permit running more than one feeder or branch circuit...

So under all '08 compliant installs, a GEC/GES is not required at additional buildings and structures...???

 

[augie47]

IMO, that's an odd exception. '08 code requires an EGC with a feeder or branch circuit supplying another building or structure and also does not permit running more than one feeder or branch circuit...

So under all '08 compliant installs, a GEC/GES is not required at additional buildings and structures...???

A single branch circuit over 20 amps, for the most part, would be useless at most separate buildings other than a small residential outbuilding. Once you add OCP at the building, that circuit becomes a feeder and GEC/GES is required so it seems the exception is manly for the receptacle/lighting outlets in smaller outbuildings where a single (or MW) 15 or 20 amp circuit is all thats needed.

 

[Smart $]

A single branch circuit over 20 amps, for the most part, would be useless at most separate buildings other than a small residential outbuilding. Once you add OCP at the building, that circuit becomes a feeder and GEC/GES is required so it seems the exception is manly for the receptacle/lighting outlets in smaller outbuildings where a single (or MW) 15 or 20 amp circuit is all thats needed.

I reread the exception... seems I glanced over it too fast and failed to realize it excepts only a branch cirucit and NOT a feeder.

 

[augie47]

makes sense.... but highly unlike you... I miss things, you don't :grin:

 

[tom baker]

The exception for BC or MWBC exists as that type of circuit will not have a lot of electrical equipment that is subject to damage in a lightning strike. Lightning will strike a building with or without electricity, a 40 or 400 amp feeder.
But there are other rules in Art 225 we have to follow. 225 requires every building to have a disconnecting means, some exceptions, and for the purposes of Art 250, a disconnecting means is not required for single circuit to a dwelling unit outbuilding, where a snap switch can be used.
The disconnect must meet the requirements for SUSE, meaning it has a neutral that can be bonded, and most often will be a overcurrent type device-IE fuses or CB. Once you have that, it becomes a feeder, and the exception in 225.32 (A) does not apply