Second ground connection

[Ken Amelin]

Here's a remote panel located in detached garage. It is wired with four conductors from service equipment that is located in main house. The ground and neutral bars are isolated. The panel also has it's own ground connection to a ground rod that is not the same ground rod as the main house.

Is the additional ground connection at the remote panel allowed?

[Aaron Miller]

Is the additional ground connection at the remote panel allowed?

It is required to have its own ground as per NEC 250.32A, each building requires its own grounding electrode system.

http://www.iaei.org/magazine/2004/01/grounding-and-bonding-methods-for-outbuildings/

[Ken Amelin]

Thanks both of you for the quick reply. - Just in time for my report.

[Al Neuman]

The ground wire from the rod is connected in the wrong place.

It should be terminated on the neutral bus.... Not the equipment ground bus.

[Gerry Bennett]

The ground wire from the rod is connected in the wrong place.

It should be terminated on the neutral bus.... Not the equipment ground bus.

Now you are going to open up a can of worms, but you are correct!

[Jerry Peck]

The ground wire from the rod is connected in the wrong place.

It should be terminated on the neutral bus.... Not the equipment ground bus.


This is not a service, the bare GEC is terminated on the correct bus. It should not be on the neutral bus.

Robert is correct.

That is a remote panel/distribution panel/etc. and the neutral is not allowed to be bonded to ground.

I also doubt that those main lugs are listed for that small of conductors.

[Gerry Bennett]

Robert is correct.

That is a remote panel/distribution panel/etc. and the neutral is not allowed to be bonded to ground.

I also doubt that those main lugs are listed for that small of conductors.

Excuse my post It was wrong! I looked at it quickly and thought of a job I did. It was a detached garage with an existing overhead 3 wire triplex wiring. The inspector (more than one) said to make it right add a ground rod but don't isolate the ground from the neutrals.
I am going to check later the reason for that,maybe someone knows.

[Jerry Peck]

It was a detached garage with an existing overhead 3 wire triplex wiring. The inspector (more than one) said to make it right add a ground rod but don't isolate the ground from the neutrals.
I am going to check later the reason for that,maybe someone knows.

Triplex has 2-hot conductors and 1-groundED conductor, but 0-groundING conductors.

Older detached garages (separate buildings) were allowed (under certain conditions) to be fed with triplex wiring at that time.

The grounded conductor served as the groundED neutral and the groundING conductor, as such, the groundED neutral was connected to the GEC going to a grounding electrode at the separate building.

The certain conditions were that there was *no* metallic path of any kind between the buildings, no phone cable, no intercom cable, no metallic water piping, *no* metallic paths between the two.

With a 4-wire feed, an equipment ground is now run with the feeders, and if the groundED neutral conductor was bonded to the GEC going to the grounding electrode, then the neutral current would try to take both paths back to the source, i.e., some neutral current would go on the intended neutral conductor, however, some neutral current would also go on the unintended GEC to the grounding electrode and to earth, then back to the source.

That is the reason why.

[Gerry Bennett]

Triplex has 2-hot conductors and 1-groundED conductor, but 0-groundING conductors.

Older detached garages (separate buildings) were allowed (under certain conditions) to be fed with triplex wiring at that time.

The grounded conductor served as the groundED neutral and the groundING conductor, as such, the groundED neutral was connected to the GEC going to a grounding electrode at the separate building.

The certain conditions were that there was *no* metallic path of any kind between the buildings, no phone cable, no intercom cable, no metallic water piping, *no* metallic paths between the two.

With a 4-wire feed, an equipment ground is now run with the feeders, and if the groundED neutral conductor was bonded to the GEC going to the grounding electrode, then the neutral current would try to take both paths back to the source, i.e., some neutral current would go on the intended neutral conductor, however, some neutral current would also go on the unintended GEC to the grounding electrode and to earth, then back to the source.

That is the reason why.

Thanks for that clear answer. We are required when doing a service ground to "jump" the meter, ground clamp below the meter, a loop and a ground clamp above the meter. The reason I heard was on occasion the water meter service man would receive a shock when he removed the meter for replacement. Would this also be some unintended neutral current?

[Jerry Peck]

Yes, it could be, but it might also be unintended current from a ground-fault. It could also be both.