[RE-wrenches] Buchanan Crimp in 1000v Applications and the NEC

Tue Nov 11 15:42:49 PST 2025

It’s been my understanding that installing a cable to cable MC4 connection
inside a junction box is against Stabuli manufacturer guidelines and that
heat and moisture dissipation are important factors with MC4 connectors,
even though they are IP68 rated. I remember hearing this reiterated at the
NABCEP conference earlier this year as well.

On Tue, Nov 11, 2025 at 6:03 PM Jason Szumlanski via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> We have had terrific success using Wagos in rooftop junction boxes for
> splicing #12 Enphase cable to #10 home run THWN. We have no issues
> whatsoever with these.
>
> Unfortunately, the #10 PV wire insulation is too large for the Wago
> 221-6XX series. We have been buying #14-#4 Polaris taps and it's getting
> very expensive. I would like an alternative.
>
> For a while we were using the King Innovation AlumiConn purple "suitcase"
> connectors for Enphase, but they are only 300V rated and I don't think the
> PV Wire insulation fits in those, either, for <300V applications.
>
> I have seen people using MC4 connectors in rooftop junction boxes like
> Blake suggested, but I wasn't sure if that is acceptable practice to use
> them this way (in an enclosure), and it does require a pretty large
> junction box. We prefer to use the EZ Solar JB-# series of boxes. The rail
> mount ones (JB-3) are pretty small, but the tile roof JB-2 is huge, and the
> shingle JB-1 is sizable as well. I guess if there is no prohibition against
> using them in an enclosure, then it should be allowed. I do like the
> watertight nature of this solution.
>
> I have seen some clowns using MC4 connectors with #10 THHN wire to make
> these splices. That's obviously no bueno. Crazy stuff...
>
>
> 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 Tue, Nov 11, 2025 at 4:44 PM Dave Tedeyan via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>> Hi Adam,
>> This response is just to you. Is NYSERDA the inspection agency you are
>> talking about? Cause they have given me issues about using Wago Nuts inside
>> a 3R box, even after I got a statement from Wago saying that it is okay to
>> put it inside a 3R box. But squirting a bit of No-Ox in there seems to make
>> them happy about it. The one time we put one inside a 3R panel board to
>> extend a short wire and forgot to put No-Ox on that one, they gave us a 2
>> out of 5 on the inspection, even though that was the only thing noted in
>> the entire inspection report! But I would be curious if the point you make
>> above will work with NYSERDA?
>>
>> Cheers,
>> Dave
>>
>> On Tue, Nov 11, 2025 at 4:16 PM AE Solar via RE-wrenches <
>> re-wrenches at lists.re-wrenches.org> wrote:
>>
>>> We had an inspection agency that was giving us a hard time about using
>>> buchanan crimps in junction boxes because they aren't rated for
>>> outdoor/damp locations. The point was made (on this listserve) that "*if
>>> the inside of a 3R enclosure isn't considered dry enough for a buchanan
>>> crimp/cap, then there's millions of 3R panels with breakers and busbars in
>>> them that would have the same problem*". The inspection agency finally
>>> relented. We put a little No-Alox in the cap. I know that's not what your
>>> initial post was about, but tossing that in for consideration just in
>>> case...
>>>
>>> Adam Katzman (he/him)
>>> Autonomous Energies | Owner/Operator
>>> www.AutonomousEnergies.com <http://www.autonomousenergies.com>
>>> (518) 567-1468
>>>
>>>
>>>
>>>
>>> On Tue, Nov 11, 2025 at 3:51 PM Jay via RE-wrenches <
>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>
>>>> Hi Sam
>>>>
>>>> I can’t imagine being just copper it would matter, the AHJ might have a
>>>> different opinion however
>>>>
>>>> Question.
>>>> How are you insulating them?
>>>>
>>>> Jay
>>>>
>>>>
>>>> On Nov 11, 2025, at 11:15 AM, Sam Haraldson via RE-wrenches <
>>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>>
>>>> 
>>>> Wrenches,
>>>>
>>>> On the attached product spec sheet for Ideal Copper Crimps (aka
>>>> Buchanan crimps) you'll see that max voltage for the crimp is rated at 600V
>>>> but an asterisk indicates up to 1000V when "in fixtures and signs".  In our
>>>> application this is a 1000v system and we are joining pairs of #10 PV
>>>> wires.  The junctions are made in a rail-mounted, plastic j-box.  We could
>>>> not find the definition of "fixture" as it might pertain to this situation
>>>> in the NEC and as such are interested to learn more about using Buchanan
>>>> crimps for 1000V applications.
>>>>
>>>> <image.png>
>>>>
>>>>
>>>> Cheers,
>>>> Sam
>>>>
>>>> [image: OnSite Energy] <https://onsiteenergyinc.com/>
>>>>
>>>> Sam Haraldson
>>>> Operations Specialist
>>>> (406) 551-6135
>>>> 1515 N. Rouse Ave Bozeman, MT 59715
>>>> <https://www.google.com/maps/search/1515+N.+Rouse+Ave+Bozeman,+MT+59715?entry=gmail&source=g>
>>>> Locally owned and operated since 2012
>>>> [image: B Corporation] <https://onsiteenergyinc.com/bcorp>
>>>> <IDEALIndustries-Crimp Connectors.pdf>
>>>> _______________________________________________
>>>> 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
>>>>
>>>> _______________________________________________
>>> 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
>>
>> _______________________________________________
> 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/20251111/43b0cfc8/attachment.htm>