# Grounding standby generators



## McClary’s Electrical (Feb 21, 2009)

Nyspark21 said:


> Would you have to drive a ground rod to ground a generator if the housing is all plastic. Just finished setting a Kohler generator with plastic housing all around. There is no lug on the outside of the unit like other models such as generac, the unit should be grounded through the grounding conductor coming from the transfer switch though?


Did you pour a pad?


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## Nyspark21 (Dec 15, 2011)

Nope 3/4" crushed stone per manufacturers recommendations.


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## Bulldog1 (Oct 21, 2011)

Nyspark21 said:


> Nope 3/4" crushed stone per manufacturers recommendations.




No ground rod needed. You did pull a ground to the genny from the ATS right? Did you remove the bonding jumper in the genny?


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## Bulldog1 (Oct 21, 2011)

mcclary's electrical said:


> Did you pour a pad?





What you talking bout willis?


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## Nyspark21 (Dec 15, 2011)

Yes, #4 copper.


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## Bulldog1 (Oct 21, 2011)

Nyspark21 said:


> Yes, #4 copper.



Why did you use #4? What size genny? Service rated?


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## Nyspark21 (Dec 15, 2011)

20 kw whole house. #2 feeders with a #4 ground.


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## varmit (Apr 19, 2009)

Unless you have some local codes that require otherwise, you should be good with 2 hots, a neutral, and a ground. Be sure that the ground (bond) and the neutral (grounded conductor) are not connected in the generator. Run the bonding conductor in the raceway with the other conductors and connect the bond to the grounding bar in the generator and the ground bar in the transfer switch. 

The only situation where this would not be true, would be if the transfer switch switched the neutral also. In this case, the generator would be a separately derived system.


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## mbednarik (Oct 10, 2011)

Did you use AL.


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## McClary’s Electrical (Feb 21, 2009)

Bulldog1 said:


> What you talking bout willis?


 
Fits defintition of seperate structure


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## Bulldog1 (Oct 21, 2011)

mcclary's electrical said:


> Fits defintition of seperate structure


Never ever had any inspector require that here if it was a pad with no rebar. Ill look at that definition tomorrow. Thanks


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## varmit (Apr 19, 2009)

I would call the generator a piece of equipment similar to a pump or chiller, but what I think does not matter. The AHJ may have a different interpretation.


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## Bulldog1 (Oct 21, 2011)

Nyspark21 said:


> 20 kw whole house. #2 feeders with a* #4 ground.*



:001_huh:

You do realize you could of pulled a #8 for your ground right?

Or did you mean to say you used #4 for your neutral?


We usually pull #3 thhn CU for the hots, #4 for the neutral and # 8 for the ground.


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## Bulldog1 (Oct 21, 2011)

mcclary's electrical said:


> Fits defintition of seperate structure



Something that is built or constructed. That pretty much covers everything....Still we don't have to do it here.


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## brian john (Mar 11, 2007)

Bulldog1 said:


> Something that is built or constructed. That pretty much covers everything....Still we don't have to do it here.


It is a waste of an 8’ ground rod IMO.


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## Salvatoreg02 (Feb 26, 2011)

Bulldog1 said:


> :001_huh:
> 
> You do realize you could of pulled a #8 for your ground right?
> 
> ...


 
Really number #4 copper or #4alum is required for a 20kw. Number #3 is overkill...:whistling2:


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## Salvatoreg02 (Feb 26, 2011)

brian john said:


> It is a waste of an 8’ ground rod IMO.


I agree!!! Its only a manufactures spec, the code doesnt require it..


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## McClary’s Electrical (Feb 21, 2009)

Salvatoreg02 said:


> I agree!!! Its only a manufactures spec, the code doesnt require it..


 
Code does require it if the AHJ calls it a seperate structure. I've had an inspector call a single 4X4 in the gruond a seperate structure.


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## B4T (Feb 10, 2009)

Bulldog1 said:


> :001_
> We usually pull #3 thhn CU for the hots, #4 for the neutral and # 8 for the ground.


I like how we pull #3 CU and the line side of genny looks like #8.. :no:

Just can't understand how that gets a green light from UL..:blink:


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## BBQ (Nov 16, 2010)

B4T said:


> I like how we pull #3 CU and the line side of genny looks like #8.. :no:
> 
> Just can't understand how that gets a green light from UL..:blink:


Because it works fine in those conditions. 

Have you seen them melt out?


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## chicken steve (Mar 22, 2011)

mcclary's electrical said:


> I can't argue with somebody who can't read the code book.


 
i'm looking at art 225

only due to the old _'lamp pole is /isn't a structure'_ debate

regardless of it all, the engineers _still _require G-rods for them....

~CS~


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## BBQ (Nov 16, 2010)

chicken steve said:


> i'm looking at art 225
> 
> only due to the old _'lamp pole is /isn't a structure'_ debate
> 
> ...


Dammit man, can you say it frigging English!


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## brian john (Mar 11, 2007)

chicken steve said:


> i'm looking at art 225
> 
> only due to the old _'lamp pole is /isn't a structure'_ debate
> 
> ...


SOME engineers, require ground rods and I would bet most can’t tell you why, it was in the last spec they saw and did the old copy and paste.


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## Bulldog1 (Oct 21, 2011)

Salvatoreg02 said:


> Really number #4 copper or #4alum is required for a 20kw. Number #3 is overkill...:whistling2:



How you ever got a license is beyond me. You can't us table 310.15(b)(6) for a 20kw unless it is backing up everything in the house. You need to go back to school and learn the code before one of your installs burns up and kills someone......:whistling2:


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## Salvatoreg02 (Feb 26, 2011)

Bulldog1 said:


> How you ever got a license is beyond me. You can't us table 310.15(b)(6) for a 20kw unless it is backing up everything in the house. You need to go back to school and learn the code before one of your installs burns up and kills someone......:whistling2:


Hey who said I was using table 310.15 b 6?

Table 310.16 check it out maybe you'll learn something.

Sent from my iPhone using ET Forum


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## BBQ (Nov 16, 2010)

Salvatoreg02 said:


> Table 310.16 check it out maybe you'll learn something.


Learn me something ...

What code section allows sizing the conductors from the generators rating instead of the breaker size?


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## Bulldog1 (Oct 21, 2011)

BBQ said:


> Learn me something ...
> 
> What code section allows sizing the conductors from the generators rating instead of the breaker size?



The same one the inspector was using......:thumbsup:


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## Bulldog1 (Oct 21, 2011)

Salvatoreg02 said:


> Hey who said I was using table 310.15 b 6?
> 
> Table 310.16 check it out maybe you'll learn something.
> 
> Sent from my iPhone using ET Forum


What I learned is that you have no clue how to properly connect a generator according to the NEC. I also learned you are to dumb to admit you are wrong and learn the correct way to do things. Guys like you make us a lot of money because we are always fixing your violations.


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## McClary’s Electrical (Feb 21, 2009)

chicken steve said:


> i'm looking at art 225
> 
> only due to the old _'lamp pole is /isn't a structure'_ debate
> 
> ...


 
Most lamp poles re fed with a single branch circuit, or MWBC, allowing you to skip the ground rod requirement. The wires to a Gen are neither of those.


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