Here is Robin's 2 cents worth on this subject....
In a PV input circuit to a charge controller that has a 63 or 80 amp
DC-GFP, it is perfectly legal to use a small wire. That is because you
will also have the appropriate sized breaker in series with the DC-GFP
breaker. If you want to use 10AWG wire, you will need a 30 amp DC
breaker in series with your 63 or 80 amp DC-GFP breaker. The DC-GFP is
being used as a switch, not as a breaker. I used to use an 80 amp switch
on the dual Outback DC-GFP rather than a breaker, but it really does not
matter if it is a breaker or a switch. The real over-current disconnect
breaker is the device that should determine your wire size.
I'm not sure why Outback changed the DC-GFP to the battery circuit? It
will work, but you still are required to have another breaker in series
with it. The NEC intends for the DC-GFP to be installed in the PV circuit.
If you need a 100 amp DC-GFP, then you will need to use a Classic. I
cannot think of any system today that would require a 100 amp DC-GFP though.
Robin Gudgel
MidNite Solar
On 4/17/2012 11:08 AM, Nathan Stumpff wrote:
Wrenches,
In a job coming up I have a customer with an existing FM60
controller, 520 watt (!!) array. We are doing a ton of work,
including adding a 4 kW solar array with Classic 150 charge
controller. I am trying to figure out how to handle the GFP.
For the Classic, I need a 90 or 100 A output breaker minimum. 80 A
is not an option. The OutBack dual GFP is 80 A, and so it not an
option.
Is there a 100 A GFP breaker assembly I have just never seen? Is
there a way to use the Classic's GFP to run an external relay via
AUX (to trip the FM60 output breaker at the same time)? Any ideas?
Thanks,
-Nathan
--
Nathan J. Stumpff - Arctic Sun, LLC
NABCEP Ceritified PV Installer #091209-175
nat...@arcticsun-llc.com <mailto:nat...@arcticsun-llc.com>
Office: 907/457-1297
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