[RE-wrenches] down-sizing main breaker

[Richard L Ratico]

Hi Nick,

I may not be entirely clear on your situation, but I interpret 690.64(B)(2),
literally or otherwise, as meaning a busbar, or a conductor used in the SAME WAY
as a busbar, rather than as a feeder. By that, I mean the conductor would have
the solar breaker's energy tapped into it in such a way that the conductor
downstream of the tap could at times see the sum of the solar current and grid
current exceed the conductors ampacity.

Dick Ratico
Solarwind Electric

--- You wrote:
if you read 690.64b it does mention both the buss rating AND conductors.

for years and years I thought it was just for the buss rating until i got called
recently for the feeders being undersized and unable to accommodate the solar
within 120%. I see a lot of sentiments in this thread that it is only for
busing, and I would really like to discover a reference to that. Someone told me
something about the difference of having main lugs and main breakers in the sub
panel... i am looking into it.

>From the literal of 690.64 it would seem that if you are fed with #4 than you
are stuck with 120% of 100a regardless of the sub panel rating.

nick
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