[RE-wrenches] Insulation Resistance Testing with Klein ET600

Sun Apr 6 15:08:39 PDT 2025

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 <dave at sungineersolar.com> 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 <
> re-wrenches at lists.re-wrenches.org> 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 <david at quattrosolar.com>
>> 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 <
>>> jason at floridasolardesigngroup.com> 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 <david at quattrosolar.com>
>>>> 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 <
>>>>> re-wrenches at lists.re-wrenches.org> 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: RE-wrenches at 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 at 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
>>
>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20250406/7b612b5e/attachment.htm>