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<p>Wrenches,</p>
<p>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.</p>
<p>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.</p>
<p>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 <a href="https://www.sanchem.com/electrical-contact-lubricant.html">https://www.sanchem.com/electrical-contact-lubricant.html</a> 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.</p>
<p>Eric Stevens, Vermont Made Energy</p>
<p id="reply-intro">On 2021-04-28 18:16, re-wrenches-request@lists.re-wrenches.org wrote:</p>
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<blockquote type="cite" style="padding: 0 0.4em; border-left: #1010ff 2px solid; margin: 0">I think the biggest issue with poor connections on the Polaris type blocks<br />is not stripping enough insulation off the wire. They need much more<br />stripped off than other types of connectors. With too much insulation<br />remaining, the screw tightens on the insulation, and the electrical<br />connection is just some loose copper tickling the inside of the barrel.<br />You wouldn't notice it at first with testing, but it would definitely start<br />to over heat over time. Might catch it with a FLIR though.<br /><br />What other connectors are 1000 v rated? This seems like more an issue of<br />having the manufacturer's retest to 1000v. I can't imagine those blocks<br />not being able to handle 1000v, but.....<br /><br />Ray Walters<br />Remote Solar<br />303 505-8760<br /><br />On 4/28/21 11:27 AM, Corey Shalanski wrote:<br /><br />Chris's reminder is a good one?the 600V rating of most insulated<br />"multi-tap" connectors pretty much limits their use to residential systems.<br />I would also keep in mind that those connectors generally have a torque<br />spec. I've definitely seen examples of meltdowns caused by poor<br />terminations - either the compression screw isn't torqued properly or the<br />conductor isn't fully inserted. To help eliminate the latter case, we used<br />to favor the Burndy models (e.g., BIT4<br /><<a href="https://www.hubbell.com/burndy/en/Products/Power-Utilities/Connectors/Lugs-Terminals/Bolted/Vinyl-Insulated/BIT4/p/2021315" target="_blank" rel="noopener noreferrer">https://www.hubbell.com/burndy/en/Products/Power-Utilities/Connectors/Lugs-Terminals/Bolted/Vinyl-Insulated/BIT4/p/2021315</a>>)<br />because they had a transparent case; I see that Polaris also now offers<br />transparent models (e.g., IT-4C<br /><<a href="http://www.nsiindustries.com/catalog/nsiproducts/polaris-mechanical-connectors/polaris-vision-tap/it-4c" target="_blank" rel="noopener noreferrer">http://www.nsiindustries.com/catalog/nsiproducts/polaris-mechanical-connectors/polaris-vision-tap/it-4c</a>><br />).<br /><br />--<br />Corey Shalanski<br />Jah Light Solar<br />Portland, Jamaica<br /><br /><br />On Wed, Apr 28, 2021 at 7:38 AM Chris Sparadeo <<a href="mailto:sparadeo.chris@gmail.com">sparadeo.chris@gmail.com</a>
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<blockquote type="cite" style="padding: 0 0.4em; border-left: #1010ff 2px solid; margin: 0">Keep in mind that Wagos, Polaris lugs, Multi-tap Burndy lugs are rated<br />for 600V. I can see this being a possible use for MC4 connectors in a<br />higher voltage splice scenario, because of their 1000V/1500V ratings.</blockquote>
<br /><br />Send RE-wrenches mailing list submissions to<br /> <a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a><br /><br />To subscribe or unsubscribe via the World Wide Web, visit<br /> <a href="http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org" target="_blank" rel="noopener noreferrer">http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org</a><br />or, via email, send a message with subject or body 'help' to<br /> <a href="mailto:re-wrenches-request@lists.re-wrenches.org">re-wrenches-request@lists.re-wrenches.org</a><br /><br />You can reach the person managing the list at<br /> <a href="mailto:re-wrenches-owner@lists.re-wrenches.org">re-wrenches-owner@lists.re-wrenches.org</a><br /><br />When replying, please edit your Subject line so it is more specific<br />than "Re: Contents of RE-wrenches digest..."<br /><br /><br />When responding to posts within the Digest, be sure to restore the Subject: line to the original, and please edit out any extraneous lines from the quoted message.<br /> <br /><br />Today's Topics:<br /><br /> 1. Re: MC4s are listed for THWN, right? (Blake Gleason)<br /><br /><br />----------------------------------------------------------------------<br /><br />Message: 1<br />Date: Wed, 28 Apr 2021 15:13:51 -0700<br />From: Blake Gleason <<a href="mailto:blake@sunlightandpower.com">blake@sunlightandpower.com</a>><br />To: RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>><br />Subject: Re: [RE-wrenches] MC4s are listed for THWN, right?<br />Message-ID:<br /> <<a href="mailto:CAJVVAurNwUhVTnE+QtqVMoC7kSa1DOB36L2UTDyyFeJ756Gz+w@mail.gmail.com">CAJVVAurNwUhVTnE+QtqVMoC7kSa1DOB36L2UTDyyFeJ756Gz+w@mail.gmail.com</a>><br />Content-Type: text/plain; charset="utf-8"<br /><br />Great discussion, all. Thank you.<br /><br />For 1000V (where we also tend to favor MC-style connectors), we are<br />connecting PVWire to 1000V-rated XHHW-2 (which is not PVC), and always<br />inside a 3R box.<br /><br />Blake<br /><br />On Wed, Apr 28, 2021 at 9:00 AM Ray <<a href="mailto:ray@solarray.com">ray@solarray.com</a>> wrote:<br /><br /></blockquote>
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