ground rod

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newinspector1

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If you have a 200 amp panel that goes to a 30 amp sub-panel for a timer for a lagoon would a ground rod be required at both panels. I thought yes, but the electrician thinks not. Who is right?
 
newinspector1 said:
If you have a 200 amp panel that goes to a 30 amp sub-panel for a timer for a lagoon would a ground rod be required at both panels. I thought yes, but the electrician thinks not. Who is right?
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Maybe you, maybe him. We need more info. Is the 30 amp sub panel detached from the original structure? If it's on the opposite side of house, (but still attached) then then answer is no, but if it's a post out in yard with a subpanel, or also detached structure w/ subpanel, both of those would require a GES.
 
It depends on whether the panel is just one dp breaker or if the panel had more than 2 circuits. If this is simply a 240v circuit and a disconnect out at the lagoon then I say no based on art. 225.30
 
Dennis Alwon said:
It depends on whether the panel is just one dp breaker or if the panel had more than 2 circuits. If this is simply a 240v circuit and a disconnect out at the lagoon then I say no based on art. 225.30
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Even by that description, it's still a seperate structure. So IMO 250.32 (a) applies
 
mcclary's electrical said:
Even by that description, it's still a seperate structure. So IMO 250.32 (a) applies
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Yes, but the exception to 250.32(A) would allow you to omit the grounding electrode at the separate building if the building is supplied by a single branch circuit, which is what Dennis was eluding to.

Chris
 
mcclary's electrical said:
Even by that description, it's still a seperate structure. So IMO 250.32 (a) applies
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I agree it is a separate structure but if it is just a MWBC then there is no need to use 250.32. Look at the except. to 250.32(a).

250.32 Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s).
(A) Grounding Electrode. Building(s) or structure(s) supplied by feeder(s) or branch circuit(s) shall have a grounding electrode or grounding electrode system installed in accordance with Part III of Article 250. The grounding electrode conductor(s) shall be connected in accordance with 250.32(B) or (C). Where there is no existing grounding electrode, the grounding electrode(s) required in 250.50 shall be installed.
Exception: A grounding electrode shall not be required where only a single branch circuit, including a multiwire branch circuit, supplies the building or structure and the branch circuit includes an equipment grounding conductor for grounding the normally non?current-carrying metal parts of equipment.
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raider1 said:
Yes, but the exception to 250.32(A) would allow you to omit the grounding electrode at the separate building if the building is supplied by a single branch circuit, which is what Dennis was eluding to.

Chris
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It would not be a branch circuit if it's feeding a 30 amp panel, it would be a feeder. If you want to say it applies to feeders, then a dweliing doesn't need a ground rod, since it's being fed by one big single MWBC.
 
mcclary's electrical said:
If there's (ONE) breaker at the fiinal destination,,,,then this is not a branch circuit.
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So if I install a non fused disconnect at the structure then then it is a branch circuit. Add the breaker and I must install a ground rod. Hummmm. I think you are correct with the interpretation of code based on the definition of feeder and branch circuit, but it does not make sense. I also don't believe that is the intent of this section. FWIW-- nothing....
 
Dennis Alwon said:
So if I install a non fused disconnect at the structure then then it is a branch circuit. Add the breaker and I must install a ground rod. Hummmm. I think you are correct with the interpretation of code based on the definition of feeder and branch circuit, but it does not make sense. I also don't believe that is the intent of this section. FWIW-- nothing....
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I agree with mcclary's. The definition of a feeder and branch circuit require a ground rod if there is a breaker or fuse there. It might not be the intent of the CMP but that's what it says. Maybe a suggestion to reword should be made. Something like, Where a building or structure is supplied by a feeder employing only one branch circuit, including a MWBC, then no GES is required.
 
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