Is 4/0 AL SER good for 200A in NC?

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Buck Parrish said:
My opinion on why all this was started. It was because so many people were installing a 6 motions of the hand 200A outside panel with no main.
Then feeding a full panel inside on a 90A breaker with #2 SER AL then putting the condenser, the AC, stove and water heater on the outside panel. Dryer on the inside panel. They were maxing out the #2 AL.

Just my opinion.
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What was the point of 6 motions of the hand panel outside if they ran everything off the inside panel?
 
kwired said:
What was the point of 6 motions of the hand panel outside if they ran everything off the inside panel?
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The big 240V stuff went on the outside panel including the sub panel. All the branch circuits and the dryer went on the inside sub panel. They used a 200A main lug panel inside for the sub panel simply because they needed more spaces then most 100A panels. The inside panel was fed with a 90A breaker
 
Buck Parrish said:
The big 240V stuff went on the outside panel including the sub panel. All the branch circuits and the dryer went on the inside sub panel. They used a 200A main lug panel inside for the sub panel simply because they needed more spaces then most 100A panels. The inside panel was fed with a 90A breaker
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In that case the inside panel could been on a say a 40 amp feeder if that were all the load calculation was for it.

Can not protect the #2 aluminum with a 100 amp breaker if it is not supplying the entire dwelling load though, so 90 was proper.
 
letgomywago said:
90 is cheaper too
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Where I normally purchase square D breakers 80, 90 and 100 are all same price.

I could see different prices at say big box stores though, but would guess 90 is higher if even available simply because they likely purchase those in much larger quantities, 80 and 90 also would take up precious shelf space for an item that likely doesn't move as fast and that could factor in selling price even if they purchase them for same price.
 
kwired said:
Where I normally purchase square D breakers 80, 90 and 100 are all same price.

I could see different prices at say big box stores though, but would guess 90 is higher if even available simply because they likely purchase those in much larger quantities, 80 and 90 also would take up precious shelf space for an item that likely doesn't move as fast and that could factor in selling price even if they purchase them for same price.
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Eaton and siemens at my supply houses are like 10 bucks cheaper for a 90 vs a 100.

Idk why.
 
kwired said:
In that case the inside panel could been on a say a 40 amp feeder if that were all the load calculation was for it.

Can not protect the #2 aluminum with a 100 amp breaker if it is not supplying the entire dwelling load though, so 90 was proper.
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My point was the electricians were maxing out the load capacity of the #2AL to the inside panel and it was causing alot of problems. That imo is the reason the nec changed the ruling about if it is the entire load of the sfd or just part of the load is on the SER
 
Buck Parrish said:
My point was the electricians were maxing out the load capacity of the #2AL to the inside panel and it was causing alot of problems. That imo is the reason the nec changed the ruling about if it is the entire load of the sfd or just part of the load is on the SER
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It had to be supplying the entire load of a dwelling like forever to be able to use the reduced size conductor. Not sure when that came into play but probably at least back into 1960's maybe even further back.
 
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