[RE-wrenches] MC4s are listed for THWN, right?

[drake.chamberlin at redwoodalliance.org]

On a practical note, MC-4 functions fine with THHN inside a weather 
proof enclosure. It will not seal, due to the smaller overall diameter 
of the cable.

THHN is rated for 90C. It is not sunlight resistant, and should never be 
used exposed.

---


On 2021-04-26 23:16, frenergy wrote:
> Blake,
> 
>             Its great to get definitive clarification on this MC4/THHN
> issue, we've been using 4-14 Polaris connectors with good results. 
> Being inside a Nema3 can and having silicone grease in the Polaris
> makes for a solid, durable connection.  Inspecting some of these that
> are now 17 years in the field shows very good condition for the wire
> landing in the Polaris and the condition of THWN-2 wire insulation. 
> We haven't had the best of luck with Buchanans.
> 
> Bill
> 
> Feather River Solar Electric
> Bill Battagin, Owner
> 4291 Nelson St.
> Taylorsville, CA 95983
> 530.284.7849
> CA Lic 874049
> www.frenergy.net
> 
> On 4/26/2021 5:41 PM, Blake Gleason wrote:
>> Corey,
>> 
>> Thank you!  Agreed, the message from Staubli's Eng dept is much less 
>> confusing (with the exception of the statement about THHN tending to 
>> be solid vs stranded).
>> 
>> All -
>> What are you folks using to transition from PV Wire to THHN/THWN-2 
>> inside a junction box?  We used to use split bolts, which make an 
>> awesome electrical connection, but are time-consuming and not easily 
>> serviceable.  Wire nuts (the right ones) are Listed, but never felt 
>> reliable for that purpose.  Same for WAGO levers.  I hear about people 
>> using Buchanan splice caps, but I wonder about trading one set of 
>> crimping problems for another.  And of course, the only problem with 
>> using THHN in an MC4 is that the compression gland may not be as 
>> watertight as it is with PVWire, and the Buchanans certainly are not 
>> watertight.  Terminal blocks generally aren't listed, definitely 
>> aren't watertight, and raise inspectors' eyebrows.  Why is this so 
>> hard for me??
>> 
>> Best,
>> Blake
>> Thanks
>> 
> 
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