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Friends:<br><br>
I have heard, but I have not researched myself, a provision in the code
where one could dedicate a panel to be an "AC combiner" to
collect the outputs of multiple inverters. You would not install
any branch circuit breakers and thereby eliminate the need to comply with
the 120% rule. This scenario has never occurred in any
projects we have designed, which is why I have not researched the code in
this regard.<br><br>
For a theoretic discussion, however, I wonder this: Even though you
have eliminated branch circuits from the equation, you still have the
potential to overload the buss bars in or the feeder to the breaker panel
in question. If a fault occurs in the panel or feeder, you still
have sum of the feeder breaker and the inverter breakers feeding the
panel and the feeder in excess of what either is rated for. Is this
not a concern? Faults can occur other than in branch circuits,
faults such as a wrench dropped across the buss, backhoe fade, defective
inverter breaker or compromised insulation. Such a fault could
cause catastrophic failure of the panel and/or feeder. Has anyone
else pondered this question?<br><br>
William Miller<br><br>
PS: I realize a fault in the feeder means that you have fault
current below the feeder rating from either direction, but what about at
the point of the failure?<br><br>
Wm<br><br>
<br><br>
At 09:38 AM 1/22/2012, you wrote:<br>
<blockquote type=cite class=cite cite>Hi Nick,<br><br>
I see (2011) 705.12 (d) where it talks about " supplying
branch circuits as the area where it changes.<br><br>
ie w/o branch circuits then all circuits are protected by the breakers as
long as the main buss isn't exceeded by the solar input of
course.<br><br>
But in putting in that metering device plugged into a outlet, now you
have a branch circuit and hence the need to comply with 705.12 (D)
2.<br><br>
But I could be wrong.<br><br>
jay<br><br>
peltz power<br><br>
<br><br>
<br>
On Jan 22, 2012, at 8:36 AM, Nick Vida wrote:<br><br>
<blockquote type=cite class=cite cite>That is very interesting Jay, do
you have a code reference for no derate needed for your solar
accumulation panel?<br><br>
Thanks,<br><br>
Nick Vida<br><br>
<br>
btw- Rich, thanks for Bernie Sanders.<br>
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