Marco, I second Chris' suggestion. Disconnect all strings at the combiner. Check VOC PV+ to ground, and PV- to ground on each string, and PV+ to PV-. This should point you to the faulty string. If the string consists of 10 modules, each with VOC of 30 volts then you should see +300V from PV+ to PV- (assuming negatively grounded array), and 0 volts PV+ to ground, and 0 volts PV- to ground. If you find a string where you see +60V from PV+ to ground, and -240V PV- to ground, your ground fault is on that string and is likely between the 2nd and 3rd module as you move from PV + of the string to PV-. (2 * 30V voc = 60V) (8 *30V voc = 240V).
Hope this helps Carl SunRock Solar.com On Wed, Feb 6, 2013 at 12:57 AM, Marco Mangelsdorf <ma...@pvthawaii.com>wrote: > Hoo boy....I’ve got a tough one here. Trying to troubleshoot an array > ground fault with a system that has 14 strings mounted on a metal roof with > the whole roof and metal framed building being common to ground.**** > > ** ** > > Can anyone recommend any diagnostic tools out there to troubleshoot and > locate ground faults?**** > > ** ** > > Thanks,**** > > marco**** > > ** ** > > _______________________________________________ > 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 > > >
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