Is a new grounding electrode required when adding to an exisitng site?

Status
Not open for further replies.
kameele

kameele

Member
Location
NH
We do a lot of retrofits on gas metering sites that involve adding new buildings to house additional equipment. Sometimes they get a new service, most times not. As a matter of practice, we always add a ground ring with a grounding rod around the new building. it gets bonded to the existing grounding system, the new building, any rebar, etc.

A customer recently asked if that was necessary--could the new building be grounded just to the exisitng system without the expense of excavating and installing the loop and rod? I did a quick read though 250 and could not come up with anything that would actually require one method or the other. Seems like I'm missing something I should know.

I like our method of getting an assured ground level for the entire site. But if the simpler way gets you the same thing, everyone wants to save money these days.

any input would be greatly appreciated.
 
I think, but I am not certain, that art 250.32 requires a GE at the new structure. Is the ground loop required? You could just drive 2 rods and be done or use a CEE at the new site (my preference). You also would not need the rods if you install a ground ring.
 
Dennis-I think that does cover it. I'll have to read it again a couple of times to make sure. Pardon my ignorance, but what is a CEE? it will probably be a D'oh moment for me, but all I can come up with at the moment is EGC and GEC.

Thanks
 
kameele said:
We do a lot of retrofits on gas metering sites that involve adding new buildings to house additional equipment. Sometimes they get a new service, most times not. As a matter of practice, we always add a ground ring with a grounding rod around the new building. it gets bonded to the existing grounding system, the new building, any rebar, etc.

A customer recently asked if that was necessary--could the new building be grounded just to the exisitng system without the expense of excavating and installing the loop and rod? I did a quick read though 250 and could not come up with anything that would actually require one method or the other. Seems like I'm missing something I should know.

I like our method of getting an assured ground level for the entire site. But if the simpler way gets you the same thing, everyone wants to save money these days.

any input would be greatly appreciated.
Click to expand...


When you say gas metering sites, is this work for the gas company? If so, do they have a spec or standard that you may be following?
 
The particluar project that I'm working on does have a construction spec that includes grounding, but it only defines how to ground, not what grounds are required. Most others are not much more detailed.

and thanks for the CEE (AKA Ufer ground?)
 
kameele said:
The particluar project that I'm working on does have a construction spec that includes grounding, but it only defines how to ground, not what grounds are required. Most others are not much more detailed.

and thanks for the CEE (AKA Ufer ground?)
Click to expand...
Regarding NEC 2008 Edition, the grounding at a new building if fed by a feeder or branch circuit has to meet all the requirements of Article 250 Part III [ref: 250.32(A)].

That gist of the preceding is that the grounding of the new building is required to be the same as if it were a service feeding the building, with the exception that there will be no main bonding jumper (i.e. grounded conductor remains isolated from grounding system).
 
Status
Not open for further replies.
Top