320 Service, two main breakers

[Sparky Adam]

Here's a good one:

Standard single phase 320a meter base fed underground. Municipality wants the disconnect to contain the SBJ.

Two 200a main breaker cans as emergency service disconnects on each side of the meter can, each feeding a 200a sub panel inside.

Municipality requires a Ufer with #4 as GEC as well as a supplemental ground rod with a #6.

Question: which disconnect would the GEC go to?

 

[infinity]

I think that you meant MBJ (not SBJ) which would be in the service disconnects. Can you just run the GEC's to the meter base?

 

[don_resqcapt19]

Here's a good one:

Standard single phase 320a meter base fed underground. Municipality wants the disconnect to contain the SBJ.

Two 200a main breaker cans as emergency service disconnects on each side of the meter can, each feeding a 200a sub panel inside.

Municipality requires a Ufer with #4 as GEC as well as a supplemental ground rod with a #6.

Question: which disconnect would the GEC go to?

See 250.64(D). If you cannot make a GEC connection on the line side of the service disconnects, you will have to run a GEC to each disconnect.

 

[Sparky Adam]

See 250.64(D). If you cannot make a GEC connection on the line side of the service disconnects, you will have to run a GEC to each disconnect.

Why is that? Wouldn't a ground bus bar accomplish the same thing and allow us to run a single GEC (ufer) to the ground bus bar and then individual wires to each main disconnect? I only ask this as a thought experiment in order to discover creative ways to apply the code.

 

[Sparky Adam]

I think that you meant MBJ (not SBJ) which would be in the service disconnects. Can you just run the GEC's to the meter base?

My post states that the AHJ won't allow the main bonding jumper in the meter can.

 

[Little Bill]

My post states that the AHJ won't allow the main bonding jumper in the meter can.

Didn't see that stated in your earlier posts.

 

[infinity]

My post states that the AHJ won't allow the main bonding jumper in the meter can.

The main bonding jumper is not permitted in there anyway so the AHJ is correct on that one. Some locales do allow the GEC to terminate in the meter enclosure.

 

[jaggedben]

Why is that? Wouldn't a ground bus bar accomplish the same thing and allow us to run a single GEC (ufer) to the ground bus bar and then individual wires to each main disconnect? I only ask this as a thought experiment in order to discover creative ways to apply the code.

You can run separate GECs to each disconnect, or do a single GEC from the electrodes and make taps to each disconnect. Both are allowed, so whatever you like. I think you could even run four GECs (one from each disconect to each of your two electrodes).
Read the section Don quoted, it's better than us trying to paraphrase it.

Your connections have to be irreversible, or else a busbar has to meet certain size requirements.

 

[electrofelon]

My post states that the AHJ won't allow the main bonding jumper in the meter can.

The main bonding jumper is not permitted in there anyway so the AHJ is correct on that one. Some locales do allow the GEC to terminate in the meter enclosure.

Perhaps Adam means that he is not allowed to bond the Ct cabinet directly to the neutral in the CT cabinet? I have a utility that does not allow that either - you musty run a bonding jumper back to the service disconnect to bond the CT cabinet. Even if allowed, that wouldnt be a MBJ.

 

[electrofelon]

You can run separate GECs to each disconnect, or do a single GEC from the electrodes and make taps to each disconnect. Both are allowed, so whatever you like. I think you could even run four GECs (one from each disconect to each of your two electrodes).
Read the section Don quoted, it's better than us trying to paraphrase it.

Your connections have to be irreversible, or else a busbar has to meet certain size requirements.

The connections of the tap conductors to the GEC do not have to be irreversible.

 

[don_resqcapt19]

Why is that? Wouldn't a ground bus bar accomplish the same thing and allow us to run a single GEC (ufer) to the ground bus bar and then individual wires to each main disconnect? I only ask this as a thought experiment in order to discover creative ways to apply the code.

Read the code section for the options on how you can make the connection in each service disconnect.

 

[Sberry]

 

[Dennis Alwon]

View attachment 2565705

How is this relevant to the op's question?

 

[Sberry]

While the disc are not on the outside note a wire from each to the electrodes,,, and a picture adds a bit to the thread,,, no?

 

[electrofelon]

While the disc are not on the outside note a wire from each to the electrodes,,, and a picture adds a bit to the thread,,, no?

Would you mind describing what you have? So there are two service disconnect enclosures inside? Are two rods the only grounding electrodes? Does the GEC loop thru the rods and back to the second enclosure or is it two pieces of wire with 4 acorns?

 

[Sberry]

Just 2 wires continious thru 2 acorns to 2 rods but,,,, and this was really before the recent code about uffer but I have a steel building, rods in the footing all the way around and a deep footing on a loading dock I had to pump a little water to pour whole mat sitting in ground water, I was younger at the time and thought if thats good I drove a couple rods below that and wired to the frame so I have a god of steel sitting in and with a bit of water behind it.
Then,,, I guess I had number 2 maybe and bond each N bar to the steel. Bolt for the lug welded to the building.

 

[Sberry]

I really hate to show panel pics but have 2-200, one I had was 200RB and used it indoor and it feeds the outbuildings and have a 300 synch hooked to the feed thru lugs (with 100 breaker added) and 200 inside. Then, 5 panels, office, air comps and to far sides, very short branches and allowed for a welder recept local,,, but most of the heavy load is next to the main,,,, or what could be heavy lets say.

 

[Dennis Alwon]

While the disc are not on the outside note a wire from each to the electrodes,,, and a picture adds a bit to the thread,,, no?

Sorry I didn't realize there were 2 discos inside. I should have realized it.

 

[Sberry]

I do this fast am not always clear or complete.

 

[Sberry]

The side of the dock is 4 ft below grade and had water behind it and in the foot when I dug it.