[RE-wrenches] GFP and multiple charge controllers

[William Miller]

Friends:

Here is a related problem:  If we use an 80 amp GFD (ground fault 
detection) breaker, even for a very small array, we have to use 3AWG CU 
wire from the battery buss to the breaker and from the breaker to the FM or 
MX60.  This seems like a big hassle for 5 or 10 amps of charging.  A 
variety of sizes of GFD breakers would be helpful.

Here is a bigger problem:  GFD breakers don't really work.  All they do is 
turn off the charge function in hopes that someone will find the 
problem.  In the meantime, the negative-to-ground bond is removed and 
module mounting framework could be energized.  PV GFD breakers are 
completely different from standard AC GFDI (ground fault detection and 
interruption) receptacles and circuit breakers.  The AC versions interrupt 
power upstream, the PV versions interrupt power downstream from the fault.

See: 
http://millersolar.com/MillerSolar/case_studies/ground_fauilt/_ground_fault.html 
for some musings on the subject.

As they say on TV: "There had to be a better way!"

William Miller





At 05:54 PM 4/17/2012, Kent Osterberg wrote:
>Nathan,
>
>I don't think anyone makes a 100-amp PV GFP. The panel mount breaker model 
>that's being used for the PV GFP doesn't include a 100-amp breaker.
>
>The Classic has a built-in GFP so you shouldn't need an external GFP for 
>it. You will need to add a GFP for the FM60 - a single 80-amp GFP would work.
>
>You can use the dual 80-amp GFP and shut down both PV arrays at the same 
>time if the GFP is wired to disconnect the PV array from the charge 
>controller input. That's where Outback's instructions used to show the 
>GFP, and it is a better place for it than on the charge controller output 
>anyway. Midnite's instructions show the GFP on the charge controller 
>input, but their 80-amp GFP is a single.
>
>Kent Osterberg
>Blue Mountain Solar, Inc.
><http://www.bluemountainsolar.com>www.bluemountainsolar.com
>
>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
>><mailto:nathan at arcticsun-llc.com>nathan at arcticsun-llc.com
>>Office: 907/457-1297
>_______________________________________________
>List sponsored by Home Power magazine
>
>List Address: RE-wrenches at lists.re-wrenches.org
>
>Options & settings:
>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
>List-Archive: 
>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
>List rules & etiquette:
>www.re-wrenches.org/etiquette.htm
>
>Check out participant bios:
>www.members.re-wrenches.org
>
>
>No virus found in this incoming message.
>Checked by AVG - www.avg.com
>Version: 8.5.455 / Virus Database: 271.1.1/4341 - Release Date: 04/16/12 
>18:34:00

Miller Solar
Voice :805-438-5600
email: william at millersolar.com
http://millersolar.com
License No. C-10-773985
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20120417/c4a2e3be/attachment-0003.html>