grounding at the meter

[stennie_electric]

Hi came across a service today that the external meter housing was grounded (two grounding conductors), but no ground cable was extended into the main panel. The neutral and ground bars in the main panel are bonded and the connections are mixed on each. Service was installed in the late 80s. The customer needs to have a sub panel ran for an outbuilding. Do I need to extend the grounds from the meter housing to the main panel? Should the main panel not be bonded since the neutral and ground terminate into the meter housing (assuming bonding occurs there, haven't opened it)? I've just never came across a fairly modern service where there is no grounding in the main panel. I looked over section 250 of the NEC for clarification to see if I was missing something.

Any help would be appreciated - thank you!

 

[roger]

The GEC can stay in the meter, the Main Bonding Jumper is correct being that it is installed in the Main Service Disconnect. You will need to pull an EGC to the subpanel.

 

[stennie_electric]

The GEC can stay in the meter, the Main Bonding Jumper is correct being that it is installed in the Main Service Disconnect. You will need to pull an EGC to the subpanel.

Understood, so just run the ground and neutral off of the MDP bars, bringing 4 wire to the sub panel. Sub panel is unbonded and I need a additional ground rod since it's a detached building.

 

[roger]

You will have to bond the EGC to the enclosure at the sub panel and depending on how your local inspectors handle it you may need two rods

 

[stennie_electric]

You will have to bond the EGC to the enclosure at the sub panel and depending on how your local inspectors handle it you may need two rods

I understand the possible need for two grounds in the out building depending on local code, but why would I bond the ground and neutrals there?

"If its a sub panel that is fed out of a main panel your grounding would be either your conduit or other recognized method Art.250.118, you don't treat it as a seperate service, all your main grounding should be at the first point of disconnect, at the sub-panel you would not bond the grounded conductor."

grounding a sub panel at a separate building

do I carry the grounding/bonding electrode wire to the new subpanel in a seperate outbuilding or do I have to drive a new ground rod and then re-bond the whole thing like a new service? [ June 06, 2003, 11:31 PM: Message edited by: dia480 ]

forums.mikeholt.com

 

[infinity]

I understand the possible need for two grounds in the out building depending on local code, but why would I bond the ground and neutrals there?

You would not bond the neutral in the panel at the separate structure. You have a 4-wire feeder. The neutral goes to the neutral bus and the EGC goes to the EGC bus. Your GEC from the electrodes goes to the EGC bus. The neutral is not bonded.

 

[roger]

I understand the possible need for two grounds in the out building depending on local code, but why would I bond the ground and neutrals there?

You won't, I said bond the EGC to the enclosure.

 

[roger]

The neutral is isolated.

 

[stennie_electric]

You won't, I said bond the EGC to the enclosure.

Apologies, I just realized I misread that

 

[roger]

Apologies, I just realized I misread that

No problem.

 

[stennie_electric]

No problem.

Thank you for your help!