Generator Grounding

[chris1971]

I have a customer that is not connected to the Grid. He has a fixed generator that he will use for his electrical source for his home. My questions are:

1. Does the generator need a ground rod at the generator?

2. Do we need to run a ground wire from the generator to the house panel?

3. Do we treat this as a typical home and drive a ground rod at the house and do the grounding and bonding like its typically done?

Your input is greatly appreciated.

Thank you.

 

[cpal]

it would be in your best interest to study 250.30, and reference section.

If the gen is remote from the structure served 250.32 might apply also.

after you read these section you may be able to focus on specific issues.

 

[nakulak]

some questions to consider (besides the ones already asked):

-is this a temporary installation
-is the generator vehicle mounted (mounted to a frame on wheels)
-does the generator have its own readily accessible ocpd
-is the generator in sight of the dwelling
-do they plan on ever connecting the house to the grid ? (is this a dwelling that was removed from the grid with an existing service or expects future connection ?)

example:
if its not a temporary installation, and it is going to be connected to grid in future, then install an ATS and if its switched neutral then the gen is a SDS and gets grounded.

example:
if its not withing sight of house you might need disco at service entry.

there are a lot of variables and not enough info.

(regardless, if its a sizable generator, it doesn't hurt to provide lightning protection)

 

[zbang]

Perhaps I'm being dense this morning, but if then generator is at all removed from the house, then I'd install a rod, whether or not it's required. They're cheap and do no harm.

Past that, there are too many questions before the answers.

 

[augie47]

some questions to consider (besides the ones already asked):
.......................................


example:
if its not a temporary installation, and it is going to be connected to grid in future, then install an ATS and if its switched neutral then the gen is a SDS and gets grounded.)

I don't recall ever running into this situation (generator only) so I have to admit I'm a bit lost. If there is no plan for a future utility service and no ATS, do we consider the generator a SDS ???

example:
if its not withing sight of house you might need disco at service entry.

In sight or not, would 225.32 not require a disconnect at the building ?

there are a lot of variables and not enough info.

(regardless, if its a sizable generator, it doesn't hurt to provide lightning protection)

 

[don_resqcapt19]

I don't recall ever running into this situation (generator only) so I have to admit I'm a bit lost. If there is no plan for a future utility service and no ATS, do we consider the generator a SDS ???

The generator is a SDS and 250.30 applies as well as 250.32.

In sight or not, would 225.32 not require a disconnect at the building ?

Maybe. Take a look at 702.11. On second though, this is not a standby system so does 702 even apply?

 

[chris1971]

Generator

Generator

This generator will be the primary source of electricity. The house will not be connected to the grid. (Its up in the mountains closest source of power from the grid is 10 to 15 miles away.) The generator will be in a seperate building and feed the house and the building it is in.

Do I install a ground rod at the generator?
A ground rod at the house?
One ground rod at the generator and run a ground wire from generator to the house panel and isolate the neutral and grounds?

Not sure how to proceed? Never seen this application?

 

[augie47]

This generator will be the primary source of electricity. The house will not be connected to the grid. (Its up in the mountains closest source of power from the grid is 10 to 15 miles away.) The generator will be in a seperate building and feed the house and the building it is in.

Do I install a ground rod at the generator?
A ground rod at the house?
One ground rod at the generator and run a ground wire from generator to the house panel and isolate the neutral and grounds?

Not sure how to proceed? Never seen this application?

The separate building pretty much decides it for me. (Based on '08)
Grounding electrodes as required and as available at both the house and the generator building. 250.24, 250.32
Equipment ground between the buildings 250.32
Disconnects at the house 225.32

 

[chris1971]

That makes sense. Do we isolate the neutral in the house panel and treat it like two seperate buildings?

 

[augie47]

In my opinion, yes