Hey Bob ! Hi from the west side of the hill.
This seems like an easy one... Well, maybe...
One a dry day, take a garden hose and spray different parts of the
system and see if you can
duplicate the problem and locate where the water makes it trip.
But you may have to wait a while for each spot sprayed to let it fault
out before spraying
another spot. That's how I'd start out.
This also seems kind of weird in a way because of the current necessary
for that breaker
to trip. What ? 1/2 amp or 1.0 amp or so.... That's not a real small
amount for rain.
I bet something is rusty or corroded or something like that. Please let
us know what
you find !!
boB
On 5/22/2012 7:36 PM, Bob Clark wrote:
Wrenches:
Sorry to bring up this situation again, but I could not find a
previous discussion thread that talked about step-by-step procedures
for tracking down ground faults (I believe it was John Berdner who
provided the bulk of the writing in that regard and it related to high
voltage strings---not that 75-85 volts per string is all that low).
We have an Outback FLEXpower Two system with 8, 3-module strings
(Silicon Energy 190W, 25.3Vmp, 7.5 Imp) combined in a Midnite Solar
MNPV12 combiner with breakers. The cables from the array are routed
to two different Wiley 4-string pass-through boxes (located under the
two center strings) and then off of the roof and into the PV combiner.
Up until this week the system has seen several weeks of awesome power
production. Yesterday, the rains came and the GFDI breaker tripped.
Every time it rains, the little green breaker on the GFDI trips off.
That tells me that the ground fault is occurring in a place where at
least one of the conductors on one of the strings (possibly more) is
getting wet and conducting current to ground.
It would seem to me that the most likely place for moisture to cause a
ground fault to occur in this system would be in the pass-through
boxes. This would mean removing the central modules to access the
pass-through boxes.
Any of you who have mounted the Silicon Energy modules know that the
cables are contained in trays along the side of the modules until they
are routed through conduit to the pass-through boxes. So, if there is
current going to ground from any of these cables, it could even be
occurring in any of the 9 trays along side of the modules. I do not
like the idea of tracking down a ground fault in one of these trays as
they are all interconnected.
How best (and safely) to track down where the ground fault is
occurring? Any advice as to the best and safest way to track down the
ground fault(s) would be greatly appreciated.
*Bob Clark*
*/SolarWind Energy Systems, LLC/*
_______________________________________________
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