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

[Tyrone Houck]

Come to think of it, I've never seen a properly installed staubli mc4
connection fail that wasn't subject to extreme conditions.




On Wed, Nov 12, 2025, 6:59 AM Tyrone Houck <tyronehouck at gmail.com> wrote:

> To be fair, with a standard staubli mc4 inside a properly installed jbox
> not subject to extreme pressure/temperature conditions, the only difference
> between thwn and pv cable(assuming similar stranding versions) is how
> easily the gland grabs on the wire jacket.. in that case the USE version of
> the staubli has a tighter gland. Kind of a non issue if the interior
> conditions of the box are stable and not pushing condensation inside the
> connector via pressure differential....a good reason to seal the conduit if
> it goes into conditioned space. I tighten them until they grab and in 20
> years I've never had one fail in that scenario...Just my anecdotal
> input..maybe ones might think that clownish. I can't make a claim to the
> listing requirements.
> Sunny Regards,
>
>
>
> On Tue, Nov 11, 2025, 11:45 PM Jason Szumlanski via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>> Haha, that was my comment, not Glenn's. A bulkhead fitting designed for
>> use with THWN is a different story. I was referring to a standard MC4
>> connector designed and listed for use with Type PV/USE wire only.
>>
>>
>> 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, 9:44 PM William Miller via RE-wrenches <
>> re-wrenches at lists.re-wrenches.org> wrote:
>>
>>> Glenn:
>>>
>>>
>>>
>>> I am one of those clowns:
>>>
>>>
>>>
>>>
>>> https://millersolar.com/MillerSolar/practices/PV_wiring/PV_Cable_wiring/_PV_Cable_Wiring.html
>>>
>>>
>>>
>>> William
>>>
>>>
>>>
>>> Miller Solar
>>>
>>> 17395 Oak Road, Atascadero, CA 93422
>>>
>>> 805-438-5600
>>>
>>> www.millersolar.com
>>>
>>> CA Lic. 773985
>>>
>>>
>>>
>>>
>>>
>>> *From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
>>> Behalf Of *Glenn via RE-wrenches
>>> *Sent:* Tuesday, November 11, 2025 4:11 PM
>>> *To:* RE-wrenches
>>> *Cc:* Glenn
>>> *Subject:* Re: [RE-wrenches] Buchanan Crimp in 1000v Applications and
>>> the NEC
>>>
>>>
>>>
>>>
>>>
>>> I have seen some clowns using MC4 connectors with #10 THHN wire to make
>>> these splices. That's obviously no bueno. Crazy stuff...
>>>
>>>
>>>
>>>
>>>
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