There are two junction boxes on the roof, but they are very difficult to reach (steep, high, metal, etc.)
I should be able to splice them temporarily at the inverters. I'll have to check it out. The faults usually take more than 12 hours to manifest, so it's frustrating to track them down. That's why I was hoping to narrow the scope of the investigation with some insulation tests. Given the wire management mess, I'm strongly suspecting a problem on the roof, not an inverter problem. Jason Szumlanski Principal Solar Designer | Florida Solar Design Group NABCEP Certified Solar Professional (PVIP) Florida State Certified Solar Contractor CVC56956 Florida Certified Electrical Contractor EC13013208 On Sun, Apr 6, 2025, 7:38 PM Dave Tedeyan <[email protected]> wrote: > How quick do the faults take to show up? If you can just wire nut on > temporary jumpers while you are on site, you can swap the strings at the > inverters. With an ungrounded array, you can touch one hot wire at a time > without getting zapped. But put on your gloves to be extra safe. I would > not leave things open like that overnight, but if the faults occur within > an hour or two, then you can leave it like that very temporarily to > troubleshoot. > > Also, no Jbox on the roof at all? Strange. If there were you can > disconnect and swap wires up there, or just disconnect them there and then > safely swap them at the inverters. > > Cheers, > Dave > > On Sun, Apr 6, 2025, 6:08 PM Jason Szumlanski < > [email protected]> wrote: > >> Yes, I considered swapping strings per inverter, but it is a very >> challenging roof and there is no easy way to disconnect the PV strings to >> swap them. In these cases I always prefer some sort of PV string disconnect >> that is easily accessible, but the original installer just ran strings from >> the roof to junction boxes in ridiculous locations with no additional >> disconnecting means on to the inverter. >> >> On top of that, there is no RSD/PVHCS system (which was required in this >> case, but the local AHJ is clueless apparently). So I'm dealing with high >> voltage DC and limited options to isolate conductors and make it safe for >> testing. >> >> >> Jason Szumlanski >> Principal Solar Designer | Florida Solar Design Group >> NABCEP Certified Solar Professional (PVIP) >> Florida State Certified Solar Contractor CVC56956 >> Florida Certified Electrical Contractor EC13013208 >> >> On Sun, Apr 6, 2025, 2:15 PM Dave Tedeyan <[email protected]> >> wrote: >> >>> Can you swap the strings in each inverter? Then you'll know whether the >>> issue truly lies in the inverter or the array. >>> >>> Cheers, >>> Dave >>> >>> On Sun, Apr 6, 2025, 1:35 PM Jason Szumlanski via RE-wrenches < >>> [email protected]> wrote: >>> >>>> I should mention that the other inverter also has three strings and is >>>> experiencing no faults. Neither inverter has an EGC landed in it from the >>>> array. >>>> >>>> >>>> Jason Szumlanski >>>> >>>> >>>> On Sun, Apr 6, 2025, 11:47 AM david quattro <[email protected]> >>>> wrote: >>>> >>>>> Tech support said if it’s landed in conjunction with the Load Out >>>>> ground it causes an ‘echo’ on the grounds. Can result in erroneous Arc >>>>> fault or other error codes. >>>>> I think if using a separate wire trough, that trough needs to be >>>>> physically far from the inverter and close to an electrode. >>>>> >>>>> >>>>> >>>>> On Sun, Apr 6, 2025 at 8:09 AM Jason Szumlanski < >>>>> [email protected]> wrote: >>>>> >>>>>> That's a good point. I didn't install this system, but I know for >>>>>> certain the PV EGC is not landed in either of the dual Sol-Ark inverters. >>>>>> It must be landed on a grounding terminal in a wiring trough or load >>>>>> center. I'll have to track that down. I'm not sure how the GE system is >>>>>> installed, either. >>>>>> >>>>>> >>>>>> Jason Szumlanski >>>>>> Principal Solar Designer | Florida Solar Design Group >>>>>> NABCEP Certified Solar Professional (PVIP) >>>>>> Florida State Certified Solar Contractor CVC56956 >>>>>> Florida Certified Electrical Contractor EC13013208 >>>>>> >>>>>> >>>>>> On Sun, Apr 6, 2025 at 11:03 AM david quattro <[email protected]> >>>>>> wrote: >>>>>> >>>>>>> Hi Jason, >>>>>>> SolArk tech support has told us to land the PV equipment ground >>>>>>> directly to an electrode. ie do not land the PV ground in the >>>>>>> inverter’s built in ground-bar. This detail wasn’t in their manuals >>>>>>> years >>>>>>> ago. I hope this is helpful 🤙🏼 >>>>>>> David >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Sun, Apr 6, 2025 at 7:19 AM Jason Szumlanski via RE-wrenches < >>>>>>> [email protected]> wrote: >>>>>>> >>>>>>>> If anyone is using this tester to do insulation resistance testing, >>>>>>>> I would appreciate any pointers you have. >>>>>>>> >>>>>>>> I have used it successfully to test home run DC strings from >>>>>>>> rooftop junction boxes to inverters to check for nicks in wires and >>>>>>>> hard >>>>>>>> faults to ground or short circuits. However, I am currently facing a >>>>>>>> Sol-Ark 15K with three strings of PV that all seem to cause an >>>>>>>> intermittent >>>>>>>> DC insulation fault (F24). I have isolated each string by >>>>>>>> disconnecting the >>>>>>>> other strings at the rooftop junction box. With only one string >>>>>>>> connected >>>>>>>> to the inverter, regardless of which string it is, I will eventually >>>>>>>> get >>>>>>>> the F24 error. >>>>>>>> >>>>>>>> Since I have ruled out the home run wiring, It appears the issue >>>>>>>> must be within the array somewhere. I would like to use the ET600 to >>>>>>>> help >>>>>>>> track it down, but I am reading conflicting information on how to >>>>>>>> properly >>>>>>>> undertake the test on each string. I know that I can disconnect the >>>>>>>> conductors between each PV string and the junction box and test each >>>>>>>> jumper >>>>>>>> wire individually while disconnected. But what about the PV module >>>>>>>> leads >>>>>>>> within the string of connected modules? I'm suspecting a pinched PV >>>>>>>> module >>>>>>>> lead somewhere, but I don't know where to start looking. >>>>>>>> >>>>>>>> Jason Szumlanski >>>>>>>> Florida Solar Design Group >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> List sponsored by Redwood Alliance >>>>>>>> >>>>>>>> Pay optional member dues here: http://re-wrenches.org >>>>>>>> >>>>>>>> List Address: [email protected] >>>>>>>> >>>>>>>> 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/[email protected]/ >>>>>>>> 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: [email protected] >>>> >>>> Change listserver email address & settings: >>>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >>>> >>>> There are two list archives for searching. 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