Grounding and bonding at residential service

S

Sparkycart619

Member
Location
Tn
Occupation
EC
I have a 200 amp underground, ungrounded 3 wire single phase residential service. Installing a home standby generator. Service goes as: Consists of 4 panels outside
200A meter base- 200A non fused disconnect- 200A service rated ATS panel- 200A main breaker outdoor 16 circuit panel with sub panels,hvac etc… breakers
I have 3 wire from meter base to non fused disconnect > 3 wire run from non fused disc. To ATS > 4 wire run from ATS to 8/16 main breaker panel. 4 wire run from main breaker panel to sub panels and all grounded and grounding separated in main breaker panel and after I was going off 250.186A exception, 250.186B exception and 250.30 inspector says I have to separate my N-G in the ATS because the non fused is my first means of disconnect. Doing so will cause the generator itself to become a sds.
 
Welcome to the forum.

Label the first disconnect "Emergency Disconnect - Not Service Equipment".

Or, remove that disconnect completely.
 
250.186 is for 1000 volts or more = not applicable,
Larry's idea is prudent, however, most of TN is still on the '17 Code and the "emergency disconnect" rule is not in effect.

Separating the neutral and grounds in your ATS will not make the generator a SDS. The ATS would need to switch the neutral in order for the generator to be an SDS.

Seemingly the quickest solution would be to simply follow the inspector's request.
 
augie47 said:
250.186 is for 1000 volts or more = not applicable,
Larry's idea is prudent, however, most of TN is still on the '17 Code and the "emergency disconnect" rule is not in effect.

Separating the neutral and grounds in your ATS will not make the generator a SDS. The ATS would need to switch the neutral in order for the generator to be an SDS.

Seemingly the quickest solution would be to simply follow the inspector's request.
Click to expand...
230.71 and 230.35 permanently installed generators.
 
augie47 said:
250.186 is for 1000 volts or more = not applicable,
Larry's idea is prudent, however, most of TN is still on the '17 Code and the "emergency disconnect" rule is not in effect.

Separating the neutral and grounds in your ATS will not make the generator a SDS. The ATS would need to switch the neutral in order for the generator to be an SDS.

Seemingly the quickest solution would be to simply follow the inspector's request.
Click to expand...
230.71 and 230.35 permanently installed generators.
 
at the end of the day I’m not looking to tell an inspector off or not be compliant but at the same time the book needs to be followed not just something someone says because that’s how they do it. Thank
LarryFine said:
Then it is an emergency disconnect, right?
Click to expand...
yes
 
Where are you getting those Code references ? They are not in the 2017 NEC

Likely you are referencing 230.85 for "Emergency Disconnect" (not required in 2017)_
If so, I agree with Larry... label the NF as "EMERGENCY DISCONNECT, NOT A SERVICE DISCONNECT"
The neutral will provide the grounding for it, run the 3 wires to your ATS which becomes your service disconnect (apply SERVICE DISCONNECT label), bond neutral and ground and 4 wire thereafter.
Should satisfy the inspector based on 2020 NEC
 
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