DC contactor [RE-wrenches]

[R. Sparks Scott]

	Kurt:

> If the inverter was set into the LBX mode, and the inverter transfers
over to power >loads with the grid, can't it draw 60 amps?

	Not if the input breaker has a 20 amp rating. I'm assuming here that any
inspector will use the principle of maximum available current in rating any
in-line devices. For instance, you *could*, according to code, install 60
amp plugs and receptacles on a 15 amp, zip cord appliance, it the maximum
breaker rating was 15 amps, that's all that could flow in spite of the huge
connectors. Of course, it would be a real waste of time and money, and a
temptation for some clod to plug in a giant arc welder and blow the little
breaker, but it would meet code. You couldn't, however use a 15 amp
receptacle on an actual 60 amp branch circuit, for obvious reasons.
	Anyone who is connecting 60 amps worth of appliances to a 4kw inverter
output is asking for trouble anyway. If you really need the 60 amps of
surge capacity, undersizing the circuit breaker may not work, although the
inverter could take the excess of the surge not provided by the AC input
out of the batteries when the AC 1 (or 2) input amps has been set to a
lower level. As you mention, in LBX mode, this won't happen.
	Like everything, it comes down to a case-by-case basis. My guess is that
grid-intertied systems aren't going to have a lot in the way of loads
connected to the inverter's output, as grid power is available to run most
loads. Our topic was driven by the desire to be able to drop off the grid
when charging current is no available from RE sources, so limiting the AC 1
input current and using a smaller cricuit breaker should be workable in
most instances.
	Anybody else have practical experience with the AHJ's application of
maximum available current to in-line devices???

	-S

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