I would definitely check the insulation on the AC-side wiring as Lloyd mentioned. Sometimes small faults don't show up until there is moisture in the air (or conduit) or until max current conditions. As long as you have time delay fuses property sized, it would be rare for them to blow more than once or twice over a period of many years. You could try checking the insulation with a megger, but pulling it out and replacing it might be a more sure fire bet. If it still faults after that, at least you know the wire is good.
August On Mon, Nov 1, 2021 at 3:50 PM Dave Tedeyan <d...@sungineersolar.com> wrote: > The fuses are Ferraz Shawmut Trionic TR60R. 60A, 250V. I looked them up to > find that they are time delay, RK5 type. > > I would imagine that there is monitoring, but not being my installation, I > don't have access to it. That's a good idea though to get access to see > when this is happening. > > I am also waiting to hear back as to whether it is both legs, or only one. > I've been to the site only once so far, to initially diagnose the bad fuse. > At the time, I was hoping that it was just a bad fuse since everything else > looked okay. > > Lloyd, thanks for the insulation tip. Next time I head out there, I should > pull out the wires and take a closer look. Unfortunately it's a line side > tap, so I'm not excited about removing the tap, but may be worth it if I > can't find anything else. Although come to think of it, I did find a ground > fault in the wires for another system at the same site, so the original > installers' wire pulling technique is certainly suspect. > > Cheers, > Dave > > On Mon, Nov 1, 2021, 6:05 PM Jerry Shafer <jerrysgarag...@gmail.com> > wrote: > >> Does this system have monitoring, what time of day is this happening, the >> monitoring site should show output at time of failure, what leg is tripping >> both or one side? You may want to look at the fuses they are using, rapid >> blow, slow blow, rated for the duty these are being used for. You can also >> use a data logger to get a better idea of what and when >> >> Jerry >> >> On Mon, Nov 1, 2021, 1:45 PM Lloyd Hoffstatter < >> ll...@sunstruckconsulting.com> wrote: >> >>> Dave, >>> >>> >>> >>> My first thought would be a small nick in wire insulation going to >>> ground, causing the fuse to fail over time. >>> >>> We had a similar situation with a much larger system where the culprit >>> was hard to notice… >>> >>> >>> >>> Best regards, >>> >>> Lloyd >>> >>> >>> >>> Lloyd Hoffstatter >>> >>> Sunstruck Consulting >>> >>> >>> >>> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for >>> Windows >>> >>> >>> >>> *From: *Dave Tedeyan <d...@sungineersolar.com> >>> *Sent: *Monday, November 1, 2021 4:26 PM >>> *To: *RE-wrenches <re-wrenches@lists.re-wrenches.org> >>> *Subject: *[RE-wrenches] SolarEdge inverter blowing fuses >>> >>> >>> >>> Hi All, >>> >>> >>> >>> I am servicing a system that keeps blowing fuses on the AC side, >>> although it >>> >>> appears that everything is sized correctly. It is a SolarEdge >>> SE11400A-US inverter. >>> >>> Max continuous output current is 47.5A x 1.25 = 59.4A. There is a GE >>> TG3222R >>> >>> 60A AC disconnect, and it is wired up with #6 THHN wire. The terminals >>> were tight >>> >>> and there was no evidence of arcing or burning in the past. This is >>> indoors, and not >>> >>> exposed to sunlight. No extra conductors are in the conduit. >>> >>> >>> >>> But they say that they need to replace a fuse roughly once per month. >>> Has anyone >>> >>> seen this before? Could there be some kind of fault in the inverter >>> itself that >>> >>> occasionally induces extra current? Is there any way to tweak the >>> settings so that it >>> >>> actually produces a bit more than 11.4kw? I appreciate your thoughts. >>> >>> >>> >>> Cheers, >>> >>> Dave >>> >>> >>> >>> -- >>> >>> [image: Logo] <https://www.sungineersolar.com/> >>> >>> >>> *Dave Tedeyan, P.E. Owner | Sungineer Solar* >>> >>> *p: *he | him | his >>> * a: *1653 Slaterville Rd. | Ithaca, NY 14850 >>> *w:* www.sungineersolar.com <http://www.sungineersolar.com/> >>> *c:* (607) 288-2898 >>> >>> >>> >>> >>> _______________________________________________ >>> List sponsored by Redwood Alliance >>> >>> Pay optional member dues here: http://re-wrenches.org >>> >>> List Address: RE-wrenches@lists.re-wrenches.org >>> >>> Change listserver email address & settings: >>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >>> >>> There are two list archives for searching. When one doesn't work, try >>> the other: >>> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ >>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >>> >>> List rules & etiquette: >>> http://www.re-wrenches.org/etiquette.htm >>> >>> Check out or update participant bios: >>> http://www.members.re-wrenches.org >>> >>> _______________________________________________ >> List sponsored by Redwood Alliance >> >> Pay optional member dues here: http://re-wrenches.org >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> There are two list archives for searching. When one doesn't work, try the >> other: >> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> http://www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> http://www.members.re-wrenches.org >> >> _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > >
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