current on ground

[lmchenry]

I have a 120/208 service with 13 circuits in a 2000 amp MDP. One of the equipment grounds with the feeders has 4 amps on it. Is this uncommon and where would it come from?

 

[brian john]

Typically from a down stream ground on a neutral or the ground utilized for a neutral.

 

[lmchenry]

Maybe better asked would be if in a properly installed service should there be any current on the equipment ground? Could this come from the field around the phase conductors?

 

[brian john]

Maybe better asked would be if in a properly installed service should there be any current on the equipment ground? Could this come from the field around the phase conductors?

Not normally.

 

[SG-1]

If you cannot trace the current to a specific load with a clamp-on meter, then it will be necessary to shut down loads to identify the source of the ground current.

 

[brian john]

Prior to a shut down a full visual inspection and taking voltage readings neutral to ground (with full load) and zero sequence measurements can help isolate the issue.