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

frenergy frenergy at psln.com
Thu Apr 29 09:43:29 EDT 2021


Eric,

             I like your idea of drilling the weepage holes as long as 
they are not big enough to allow critters like wasps to make a home 
inside the J-box.  We will use aluminum tape on unused mounting holes in 
the back of the box for the same reason. Lurkers welcome.

Bill

Feather River Solar Electric
Bill Battagin, Owner
4291 Nelson St.
Taylorsville, CA 95983
530.284.7849
CA Lic 874049
www.frenergy.net

On 4/28/2021 6:19 PM, ericstev at vermontel.net wrote:
>
> Wrenches,
>
> I am normally a lurker on the List, but I would like to add a fact 
> observation and a personal preference to the topics raised by this 
> discussion.
>
> First, THWN does have PVC as its primary insulation, but it is 
> sheathed in Nylon which is a polyamide plastic.  Therefore the 
> compatibility with MC4 connectors should be polyamide being squeezed 
> by the restraining bushing in the MC4, not PVC.
>
> I prefer Buchanan copper crimp connectors when splicing PV wire to 
> THWN-2 in a roof junction box.  The bared wires should be lightly 
> doped with NO-OX-ID A-Special grease 
> https://www.sanchem.com/electrical-contact-lubricant.html 
> <https://www.sanchem.com/electrical-contact-lubricant.html> before 
> sleeving and crimping with the crimp sleeve to repel entry of moisture 
> and corrosive gasses into the wire joint.  I consider the crimped 
> joint to be superior to any screw-clamped joint that would be made in 
> a Polaris style connector.  I also drill weepage holes in the bottom 
> corner of the junction box to mitigate any collection of water.
>
> Eric Stevens, Vermont Made Energy
>
>

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