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

Tue Nov 11 15:01:53 PST 2025

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
>>> Locally owned and operated since 2012
>>> [image: B Corporation] <https://onsiteenergyinc.com/bcorp>
>>> <IDEALIndustries-Crimp Connectors.pdf>
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