[RE-wrenches] down-sizing main breaker

[Richard L Ratico]

William,

I don't know if I've solved Brian's dilemma yet either. But, with regard to your
example below, if the 100 amp meter main is accepting 20 amps, or even all of
the 50 amps of PV, that would mean that the house, at that moment, presented no
load at all, and that all the PV would be backfeeding the grid, turning the
meter backwards. That, of course, would mean the main 100 amp breaker is only
handling 50 amps, well below its rating. Likewise the feeder from the house
would only be carrying the 50 amps from the PV, instead of anything near it's100
amp rating. The code can be perverse, but it's my understanding that the point
of 690.64(B) is to ensure none of the distribution components are exposed to
overcurrent, not to arbitrarily throw numbers around.

I was just kidding about offering you those 200 amp Milbank breakers. I've got
to figure out how to list them on Ebay.

Dick

--- You wrote:
Dick:

I don't believe you have solved Brian's dilemma yet.  It is my 
understanding that if one is going to install a load side tape, the back 
feed calculations need to work for every link of the distribution system 
upstream to the meter.  In the scenario you suggest, that will not be the 
case.  The 100 amp meter main on Brian's project will still  accept only 20 
amps of PV AC feed, still not satisfying his requirements.
--- end of quote ---