bonding in service disconnect

[123ozzie]

I have an unusual situation I need help with. There is a utility transformer that feeds a bank of meters. Each meter has its own disconnect. The way I understand it, this is my "service disconnect". A building about 75 feet away, is fed from the meter bank with three hots and a ground. No neutral. The feed from the meter goes to a 200 amp 480 v panel. Someone noticed there was not a cold water/building steel ground inside the panel. Should I pull a #4 (based on 250.66) from the water service, through the panel, then 75' to the meter and bond it on the neutral? Should I pull a neutral from the meter into the 200 amp panel and bond the cold water GEC there? Please keep in mind the neutral bus in the bank of meters feeds other unattached buildings. Any help with code references would be greatly appreciated. Thanks

 

[jaggedben]

I have an unusual situation I need help with. There is a utility transformer that feeds a bank of meters. Each meter has its own disconnect. The way I understand it, this is my "service disconnect". A building about 75 feet away, is fed from the meter bank with three hots and a ground. No neutral.

Are there neutral loads?

The feed from the meter goes to a 200 amp 480 v panel. Someone noticed there was not a cold water/building steel ground inside the panel. Should I pull a #4 (based on 250.66) from the water service, through the panel, then 75' to the meter and bond it on the neutral?

No, because you said there was already a 'ground' between the buildings. If the building with the panel does not have an electrode system then that needs to be solved at the building by installing electrodes or bonding existing qualifying ones.

Should I pull a neutral from the meter into the 200 amp panel and bond the cold water GEC there?

No. Especially not if if there are no neutral loads. I sincerely hope there are no neutral loads, since there's no neutral. (However, if there are neutral loads, the solution would pull a neutral and leave it isolated from from ground at the panel, and I presume stop using the ground for neutral loads.)

Please keep in mind the neutral bus in the bank of meters feeds other unattached buildings. Any help with code references would be greatly appreciated. Thanks

Start with 250.32.

 

[ptonsparky]

OP...How do you know it is an Equipment Ground? Is it an entirely separate building? When was the building wired?

 

[123ozzie]

Are there neutral loads?


No, because you said there was already a 'ground' between the buildings. If the building with the panel does not have an electrode system then that needs to be solved at the building by installing electrodes or bonding existing qualifying ones.


No. Especially not if if there are no neutral loads. I sincerely hope there are no neutral loads, since there's no neutral. (However, if there are neutral loads, the solution would pull a neutral and leave it isolated from from ground at the panel, and I presume stop using the ground for neutral loads.)


Start with 250.32.

There are no neutral loads. The panel feeds welding receptacles and a transformer which supplies the lighting and 120 v receptacles. The "ground" I spoke of is pulled in the pipe between the meter bank and the 480 v panel. It is bonded to the meter enclosure and the panel tub. Solved at the building: Are you suggesting that I bond building steel, water main, and gas main together ALONG WITH THE 480 v panel tub?

 

[123ozzie]

OP...How do you know it is an Equipment Ground? Is it an entirely separate building? When was the building wired?

The meter bank is mounted on the outside of building A, and feeds building A. It also feeds building B, which is an entirely separate building. Each building has its own meter/disconnect. The pipe feeding building B has an "equipment ground" that is bonded to the meter enclosure and the panel tub inside building B. Building is probably 40 years old and has been added onto/remodeled about 100 times.

 

[ptonsparky]

The meter bank is mounted on the outside of building A, and feeds building A. It also feeds building B, which is an entirely separate building. Each building has its own meter/disconnect. The pipe feeding building B has an "equipment ground" that is bonded to the meter enclosure and the panel tub inside building B. Building is probably 40 years old and has been added onto/remodeled about 100 times.

At one time we were allowed to run just the 4 wires to separate buildings, establish a GES and continue on. DB cable or PVC raceway and no interconnecting metallic paths between buildings were things to consider.
I notice you are Chicago...so depends on your codes at the time of installation.

Develop a GES at Building B bonding it to the EG that is in the feeder to the building. Some green tape may be all you need.

 

[augie47]

If I read correctly, sounds like you just need some bonding and a grounding electrode at the separate building. You have no 277 load and you have 480v plus and equipment ground to the building (you don't need a groundED conductor). Bond the EG to the panel and establish a grounding system to the steel and water and a ground rod. Note the secondary of your transformer also needs to be connected to to grounding electrode system.