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Electrical Simpleton
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The tap rules would most likely permit you to feed a 100 amp MAIN BREAKER panel, but I don't know how it would work with a main lug panel unless the buss was rated at 400 amps (and then it wouldn't really be a tap).

Pete
 
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Electrical Simpleton
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A long time ago you could do it. A 400 amp fused disconnect with 2 200 A MLO panels one each side.
Must be before my time... what code permitted this? Or, was it just something the inspector said was ok?

Pete
 

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Must be before my time... what code permitted this? Or, was it just something the inspector said was ok?

Pete
It was around 1977. I don't know if I have a code book that old. This was A 3 phase wild leg. One panel was 3 phase and the other was single phase. The wild leg fuse was downsized.

Another house service I have seen was CT metered with a 600 A fused disconnect and 3 225 A MLO panels. This would have been built about the same period.
 

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Electrical Simpleton
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It was around 1977. I don't know if I have a code book that old. This was A 3 phase wild leg. One panel was 3 phase and the other was single phase. The wild leg fuse was downsized.

Another house service I have seen was CT metered with a 600 A fused disconnect and 3 225 A MLO panels. This would have been built about the same period.
I looked in the 1978 NEC (oldest one I have) and I can't find a way to do it unless I'm totally missing something.

Not saying what you did or saw didn't pass... Just saying I can't find the provision for acceptance. Perhaps 480 might chime in... I believe he has some old NEC's.

Pete
 

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I looked in the 1978 NEC (oldest one I have) and I can't find a way to do it unless I'm totally missing something.

Not saying what you did or saw didn't pass... Just saying I can't find the provision for acceptance. Perhaps 480 might chime in... I believe he has some old NEC's.

Pete
The 3 phase was state inspected. The single phase house was city inspected.
Both were passed. House may have been early 70's
 
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