smaller main vs branch breaker

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xguard

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Baton Rouge, LA
The service for a house I'm working on has two 200 amp load centers next to each other. One was originally installed to provide future power for a shop, the homeowner is now ready to run power to the shop. This load center has a 200 amp main breaker and supplies SE-R 3/C 4/0 + 1/C 2/0 that runs through the attic to the other side of the house and ends in a box, that may be too small, on an exterior wall. We're planning to splice the conductors on the exterior wall for the final run to the shop.

It looks like the 4/0 SE-R should have been on a 150 amp breaker since it's not supplying a one family dwelling. Is this correct?

Options:

1. Replace 200 amp main breaker with 100 amp breaker. - I like this option though the breaker is no longer in production and may be hard to get. The current breaker has a mounting kit. Since I already have the kit could just the breaker be replaced? If I can find one. It's a GE THQMV 22kaic.

2. Add a 100 amp branch breaker. Move the 4/0 to the branch breaker by transitioning to smaller wire for terminating to the breaker. I'm not crazy about adding splices, we typically try to avoid them unless absolutely needed.

Opinions? Other options? Pros and cons? etc.
 

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Opinions?
In no particular order:

You should be able to keep the 200a breaker, since you're not feeding the same building.

A standard 100 amp 2-pole breaker will probably fit, using only the inner stabs and lugs.

That box probably is too small. It depends on the splicing and whether it'll be inspected.
 
In no particular order:

You should be able to keep the 200a breaker, since you're not feeding the same building.

A standard 100 amp 2-pole breaker will probably fit, using only the inner stabs and lugs.

That box probably is too small. It depends on the splicing and whether it'll be inspected.
any recommendations for a type of splice?
 
4/0AL is rated 180 amp and allowed to be protected by a 200 amp breaker (provided the load is 180 or less).
ah yes I see that now. Was thinking I was limited to the 60 degree column for some reason. So I could actually leave the 200 amp breaker and use tap rules for the run from the box on the exterior wall to a 100 amp load center in the shop? Using the "outside taps of unlimited length"?
 
It wouldn't be a tap as long as it's full-sized, which I'd suggest keeping full-sized.

The 100 amp main breaker at the shop building will take care of the reduction.
 
I noticed there may be in issue but hadn't dug into it. What do you see?
I see two things, if you don't mind:

1. The green screw should be in the EGC bus. If there's no hole, swap the neutrals and EGCs.

2. What appears to be a GEC should be in the service main, or at least in the grounding bus.
 
I see two things, if you don't mind:

1. The green screw should be in the EGC bus. If there's no hole, swap the neutrals and EGCs.

2. What appears to be a GEC should be in the service main, or at least in the grounding bus.
The load center in the photo is a service disconnect, it's not the one in the shop. There are two load centers next to each other that are service disconnects, this photo is of one. Each has a main breaker. Does that change anything?
 
The load center in the photo is a service disconnect, it's not the one in the shop. There are two load centers next to each other that are service disconnects, this photo is of one. Each has a main breaker. Does that change anything?
If that's a service panel, you're good.
 
The load center in the photo is a service disconnect, it's not the one in the shop. There are two load centers next to each other that are service disconnects, this photo is of one. Each has a main breaker. Does that change anything?
Of course it does. 😊

Why is there an incoming EGC (w/yellow tape)? (That's what said "sub-panel" to my mind.)

Where is the neutral-to-EGC bonding jumper? (Is that the purpose of the yellow-taped wire?)
 
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