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

Tue Nov 11 16:45:14 PST 2025

https://www.staubli.com/content/dam/ecs/technical-documentation/assembly-instructions/RE/PV_MA231-en.pdf

Page 4 states:
“Thermal stress
Ensure that the connector is not exposed to excessive thermal stress.
• Install the connector in such a way that sufficient heat dissipation is
ensured.
• Installation in areas that restrict the air flow (e.g. in large bundles,
in split looms or other housings) is not permitted.
• Direct burial of the connector is not permitted.”

I think a junction box would be considered a housing that restricts air
flow.

On Tue, Nov 11, 2025 at 7:31 PM Jason Szumlanski via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> We're talking about inside a junction box (NEMA 3R or 4, for example), not
> an "outdoor environment." Wagos (and other connectors like wire nuts,
> Polaris Taps, power distribution blocks, terminal blocks, etc) are allowed
> inside of a rooftop junction box, just like they are allowed in various
> switch boxes, enclosures, and cabinets that are suitable for the
> environment outdoors.
>
> For the same reason you can put circuit breakers inside of a NEMA 3R load
> center outdoors, you can use splice connectors of many kinds inside of a
> NEMA 3R enclosure. They do not need to be listed for "outdoors" because it
> is not outdoors. It's enclosed and adequately protected from the
> environment.
>
> In other words, any AHJ that challenges me on this, I just ask them to
> show me a circuit breaker that's listed for use in a wet location. That's
> usually enough to shut them down.
>
>
> 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, 7:11 PM Glenn <glenn.burt at glbcc.com> wrote:
>
>> I have not found a listing for Wagos in an outdoor environment.
>>
>> -Glenn
>>
>> On Nov 11, 2025 18:01, 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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