Hi Drake,
do you know how this is all done in say Germany?
I realize they have different codes ( hopefully) but how do they
address the main issue of potential bussbar overloading?
thanks,
jay
peltz power
On Jul 30, 2008, at 10:24 AM, Drake Chamberlin wrote:
Thanks to All who have replied,
First, to answer William's question
"What is a "feed-through" breaker box and what are "feed-through"
lugs?"
A feed through panel is the type of service equipment often
installed on pre-manufactured homes, where a main switch is needed
outside the building, and a limited number of loads, fed from the
outside, are also supplied. On the bottom of the busbar, there
are lugs equivalent to the lugs for the service entrance cables.
This is useful when feeder is to be installed to supply the breaker
panel in the premise that is equal to the total service amperage.
No breaker is needed for the run to the subpanel inside, since the
wiring will be equivalent to the service cable. It is similar in
function to a disconnect switch, but will typically have 4 to 8
breaker spaces.
The situation in this project is that a feed through panel is in a
separate building from the building to be supplied from that
panel. The building this panel is in has a separate electrical
service, which is commercial. The service for the residence comes
in through a separate meter, located on this same commercial
building, then goes to the feed through panel. This panel was
installed for us, for the sole purpose of allowing a feed from the
solar array.
The issue here is that the busbar will have 200 amps from the main,
and over 40 amps from the solar. No power is to be taken from the
residential service to feed the commercial building. There is no
possibility of an overload on the busbar because the house has a
main 200 A breaker that will limit the load from the panel.
It could be argued that since the line to the house will have up to
240 amps available on a 200 amp service, that is too much. I would
argue that a standard service drop can supply 10,000 amps
instantaneously.
The box is strictly to be used as an AC combiner and feed for two
inverters. By the letter of the NEC, it does not seem to be code.
I'm going to use Kent's suggestion and use a label, after running
it by the AHJ beforehand.
-Drake
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