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

Tue Nov 11 15:47:36 PST 2025

Chris - interesting.  Do you have any documentation from Staubli about this
restriction?  I haven't seen anything like that myself.  Thanks, Blake

On Tue, Nov 11, 2025 at 3:43 PM Chris Sparadeo via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> 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>
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