Steve,
A PV system GFDI integrated into the charge controller certainly
simplifies charge controller installations. Unfortunately every charge
controller that has done that has failed to correct a serious flaw in
the operation of the GFDI: under a ground fault circumstance, the
energized PV negative wire (and all those wires that are still connected
to it) remains a serious safety hazard. I can tolerate that hazard in
the PV system wiring; the PV modules are energized by sunlight so there
will be energized wires. But energized wiring running past the GFDI
should not be tolerated. NEC 690.5(C) requires a label that is visible
from the batteries warning that, if a ground fault is indicate, normally
grounded wires may be energized. That's a good warning for someone that
might be doing maintenance on the batteries. Trouble is the dc wiring to
the inverters, lights, refrigerator, or anything else may also be
energized. It's a dangerous circumstance that isn't necessary and
shouldn't be allowed. If the external GDFI device were to simply open
both PV+ and PV- conductors, there would be no hazard except between the
GFDI and the PV array. The NEC, as now written, even allows both
conductors to be opened. It's an easy fix, at least with the external
GFDI it is an easy fix, to a design flaw that has the potential to kill
someone. Outback shouldn't simply put a GFDI in the charge controller,
they should design one that is safe too.
It is safe to return to the list now. The rant is over.
Kent Osterberg
Blue Mountain Solar, Inc.
www.bluemountainsolar.com
On 5/23/2012 12:18 PM, Steve Higgins wrote:
From what I understand, future controllers from Outback Power will
incorporate the Ground Fault detection into the controller.
Steve Higgins
Sales Application Engineering Mgr
Direct 360-618-4313
Outback Power Technologies
5917 195th Street NE Arlington, Washington 98223
------------------------------------------------------------------------
*From:* re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of
*William Miller
*Sent:* Wednesday, May 23, 2012 11:22 AM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] Finding ground faults
Steve:
IMHO, a brilliant suggestion.
William Miller
At 11:19 AM 5/23/2012, you wrote:
Steve,
It would be appropriate for the GFDI to have 80-amp rated contacts
that do not have an over-current trip mechanism. IMHO, the fact that
they can trip on over-current and unnecessarily interrupt the dc
system bond is a serious design flaw.
Kent Osterberg
Blue Mountain Solar, Inc.
www.bluemountainsolar.com <http://www.bluemountainsolar.com>
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches@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
