N-G bond
- Thread starter Beckonweb
- Start date
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
Is the neutral insulated in the meter socket? Most are not.
Also, to be clear, the only thing powering the bus bar will be a 200A loads breaker that does not itself have a N-G bond. But the N and G will need to be placed on the bars in the main panel that are bonded, creating N-G bond for this breaker. Is this a problem?
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
Yes, but you will have an illegal second bond, unless you convince the inspector that the first breaker is the emergency disconnect. Doesn’t matter what the utility company approves after their meter, they have no jurisdiction.
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
Is the utility meter in with the main panel? Meaning, is this a meter-main panel?
If not, I'm not getting what is going on at all.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
No meter in the second meter base, the op is using one of those meter transfer collars there instead of the utility meter. Main meter is 400 amp, so collar will not work there.
Yes it is a meter main panel.
CORRECTION: Neutral bypasses customer meter socket and lands in backup loads panel. See attached photo.
Attachments
So the second 200A breaker would power the bus routed through the subpanel.
Would it work if we came directly from the customer meter socket back to the bus bar in the main panel? Would disconnect bus from first 200A breaker and move conductors from second 200A breaker over to the first. (Second breaker will be turned off. Not being used.) So it would just be the customer meter socket between the main and the bus. Would that eliminate the N-G issue? We would just add a 60A breaker in the main bus to power the subpanel. I can draw it up quickly to show what it would look like.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
So neutral from meter collar would tap the insulated neutral passing through the customer meter base?
The Tesla Backup Switch meter collar does not require a neutral. See attached for what we want to do. It eliminates the back up panel completely, and all of the work to move all breakers. If this was 200A service, the meter collar would go behind the utility meter and works beautifully.
Attachments
Are you suggesting modifying a 200A main breaker service panel, disconnecting the busbar from the 200A service main breaker.
Installing feeders off the load side of the 200A service main that go to your ATS,
Then installing another set of feeders from the ATS back to the panel busbar?
Like this:
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
Ahhh! So it’s not like a generator type transfer collar, it is backfed at the panel buss, and the collar just disconnects the utility.
Well Larry nailed in in post #2 so thats the answer to your original question.
I have not seen a meter/loadcenter combo in Oregon that has been evaluated or listed to be modified in this way, tapping feeders off the main and re feeding the buss, like a switch loop.
Such a modification could be field evaluated ($$$$), but the ones I have seen (like the picture I posted) are in cramped 200A meter/load-center combos all run into wire bending space issues with 312.6.
With a 400A service enclosure like shown you may indeed be able to pull it off and meet wire bending space.
I do sympathize with trying to keep it simple and elegant re-use existing gear but you can paint your self into a corner pretty quick with modifying listed service equipment for other than the intended purpose.
I have not seen a meter/loadcenter combo in Oregon that has been evaluated or listed to be modified in this way, tapping feeders off the main and re feeding the buss, like a switch loop.
Such a modification could be field evaluated ($$$$), but the ones I have seen (like the picture I posted) are in cramped 200A meter/load-center combos all run into wire bending space issues with 312.6.
With a 400A service enclosure like shown you may indeed be able to pull it off and meet wire bending space.
Then if your creating a giant switch loop (2 feeders that do not contain a neutral) I wonder if there is a issue with 300.3(B)? I suppose if both feeders were in the same raceway it would be ok physics wise.
I do sympathize with trying to keep it simple and elegant re-use existing gear but you can paint your self into a corner pretty quick with modifying listed service equipment for other than the intended purpose.
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
Not what I was asking. I wasn't talking about the added meter socket, I was asking if the main was a meter-main.
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
I think this is the age old problem of adding a generator and ATS to an existing meter-main. Usually the only solution is to add a panel for the desired back-up loads. It's not hard on new construction, but a pain on existing service since you can't modify the service meter-main combo. Any ATS added will have to be wired as a subpanel since the main is factory bonded.
Another solution is to replace the meter-main with a regular meter base, then the ATS can be the main if it is service rated. A little more difficult with a 400A service and two 200A panels. You either move all desired backed-up loads to one of the 200A panels, or use two ATS.
Another solution is to replace the meter-main with a regular meter base, then the ATS can be the main if it is service rated. A little more difficult with a 400A service and two 200A panels. You either move all desired backed-up loads to one of the 200A panels, or use two ATS.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
What the op is using is not a standard ATS, it is apparently solar with battery backup. They are selling the solar to the utility, but when the utility fails, it automatically switches to solar/ batteries, which is harder to do with a standard transferswitch.