New service to replace old... grounding

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lisco

Member
We have an existing 200A single phase panel with an UFER ground. A detached garage was built adjacent to the house where the existing service drop conductors went over the roof of the garage. Therefore the service needed to be relocated to the garage so that we would have the clearance necessary.

We built a new service with a main disconnect at the garage. The inspector told me to put a ground plate at the garage and that I do not need a grounding conductor running from the new disconnect to the existing panel (sub panel).

The UFER ground then is not tied to the service it goes directly to the sub panel. Should the grounding conductor and the grounded conductor be tied together at the sub panel?
 

electricman2

Senior Member
Location
North Carolina
Occupation
Retired Electrical Contractor
Since you have re-located the service to the garage, the circuit to the house now falls under Article 225. If you are not under the 2008 NEC, then you are permitted to bond the grounded conductor at the house panel and to the GEC and not run a seperate grounding conductor. See 250.32(B)(2). A grounding electrode is needed at the garage for the new service. FWIW, I would run the EGC and remove the bond at the house panel.
 

dnem

Senior Member
Location
Ohio
electricman2 said:
If you are not under the 2008 NEC

That's question #1

What's the chance of there being no other metallic paths between the buildings ?
That's question #2

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If you're not under '08, then you might have an option for the second building. . The building with the service is automatically building #1. . For the second building [the house] you can follow 250.32(B)(1) 4wire which includes an equipment ground
or
if there are no other metallic paths between the buildings [including communication cable shields] you would then have the option of 250.32(B)(2) 3wire which does not include an equipment ground.

With 250.32(B)(1) the 4wire feeder to the house panel is a subpanel and you treat it as a subpanel, separation of neutral from equipment grounding and isolation of neutral from the enclosure.

With 250.32(B)(2) the 3wire feeder to the house panel is a subpanel but you treat it as you would a mainpanel by bonding your neutrals and equipment grounding together and adding a bonding strap/screw to the enclosure.

Either way you need an electrode for each building and therefore bonded to each panel, 250.50.

***
If you're under '08, you must run a 4wire which includes an equipment ground and separate neutrals from equipment grounding in the house subpanel.

David
 

abe72487

Member
Location
Lewiston Idaho
New service

New service

I agree with the first inspector since the buildings are deattached. You will need a ground at the garage and a ground at the garage.
 

E.C.

Member
Man, all I can do know is read ground threads. I thinl someone could study this forever and not get it all.:cool: :D
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I agree with David, but would question why you would ever install a ground plate and not just 2 ground rods?
 
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