One other key to success with any splice method is giving the installers frequent training. Every few of months we bring some wire, wire nuts, strippers, and terminal blocks to our safety meeting and have everyone do a connection in front of an experience lead electrician. We then test the torques and do a pull test on the wires. A properly made up wire nut connection (or any good connection for that matter) is so strong that even the strongest folks can’t pull the wires out of the connection. We’ve had the spiral insides of the wire nut pop out during the pull test but the connection should still be intact. If they don’t strip the wire long enough or if they strip it too long and don’t trim it then we make them do it again.
-August *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Ray Walters *Sent:* Wednesday, June 25, 2014 11:02 AM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] AFCI disturbances. wire nuts I've had butt splices fail, due to a ratchet release type crimper that didn't pinch the wires tight enough. I now use a good old Klein crimper that puts a big indent on one side. The problem with this however, is that it damages the built in insulation. My favorite butt splice is uninsulated, and then slide adhesive shrink wrap up tubing up over the connection after. We use these on submersible pumps that are 100 ft under water with no issues. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 6/25/2014 11:43 AM, Nathan Charles wrote: Hi All, Has anybody had success with these butt splices with the adhesive shrink tubing? http://www.mcmaster.com/#butt-splices/=skb9qs Best, On Wed, Jun 25, 2014 at 1:12 PM, August Goers <aug...@luminalt.com> wrote: Hi All - We have been using outdoor Ideal brand wire nuts (the blue ones packed with waterproof gel/grease) for all of our residential DC side splices (typically #10 wire) for 10 years now and have never had a single problem. If the installers properly strip the conductors and follow the instructions I feel that these wire nuts make very robust connections. We always do a good pull test after twisting the wire nut on. I would never recommend standard wire nuts without the grease and have seen these fail numerous times during inspections of systems installed by others. Insulated terminal blocks also work well but don't have that nice waterproof grease in them to help avoid moisture issues. You can wrap them with a good splicing tape to help keep moisture out but the cost for these connections is significantly higher than wire nuts: http://solutions.3m.com/wps/portal/3M/en_US/EMDCI/Home/Products/Catalog/~? N=5433135&rt=c3 <http://solutions.3m.com/wps/portal/3M/en_US/EMDCI/Home/Products/Catalog/%7E?%0AN=5433135&rt=c3> Normally I error on the robust conservative side of the installation spectrum but in this case it sounds like I may not. Just my $0.02 Best, August -----Original Message----- From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of William Miller Sent: Wednesday, June 25, 2014 8:40 AM To: RE-wrenches Subject: Re: [RE-wrenches] AFCI disturbances. Richard: Possibly. I think I prefer din mount connector blocks. However, if a wire nut can arc internally a connector block might also. I am still wondering about this concept. William Miller Solar > On Jun 25, 2014, at 6:09 AM, richard.l.rat...@valley.net (Richard L Ratico) wrote: > > William, > Would UL listed crimp sleeves be an acceptable substitute where you > would otherwise use wirenuts? > > Dick Ratico > Solarwind Electric > > > --- You wrote: > Bob-O: > > > > When you say verboten, what does that mean? Not kosher? Frowned upon? > Disallowed by law??? > > > > I am quite curious about this subject. Here is what I have learned so far: > > > > This is a unique case where we are replacing 3 dead SMA U series > inverters with 2 US series inverters. The U series seem to all be > dying at about 12 to 14 years of age. We have about a dozen of these > to swap on our calendar and expect more. It may be that to do this > right requires that we pull new wire from the arrays. This makes the job a lot more expensive. > > > > We have never used a wire nut on a PV lead until this project. It's > not that we disapprove of wire nuts in general, it is because we know > that if we were to use them regularly we would eventually have failures and call backs. > We allow only one splice in a PV lead: between the cable provided by > the manufacturer of the module and a bulkhead mounted MC4 connector > direct to THWN in conduit > (http://millersolar.com/MillerSolar/practices/PV_wiring/PV_Cable_wirin > g/_PV_ > Cable_Wiring.html). > > > > We checked the manufacturer's listing and the wire nuts are rated for > 600 volts. We do use wire nuts on AC circuits, such as switch and > receptacle circuits in a power room. > > > > A tech at SMA told me that wire nuts "arc internally to the spring" > causing the AFCI faults. I am not aware of any process of "internal > arcing." To me, arcing means, as per the dictionary definition: "a > luminous bridge formed in a gap between two electrodes." The same > tech told me to solder the leads and apply shrink tubing. I don't > believe this is an approved method. By the way, we have spliced leads > on both US series inverters and only one is exhibiting AFCI disturbances. > > > > I do favor mounted terminal blocks, either screw or tubular type. I > need to check if the Amp model we stock are 600 volt rated. > > > > I was told by another representative from SMA that on a ground-mount > system it is legal to disable the AFCI protection. > > > > I will be troubleshooting this job tomorrow and I will let you all > know what I learn. > > > > William Miller > --- end of quote --- > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist > .html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.htm l List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org -- Nathan Charles Engineer NABCEP Certified PV Installation Professional #042013-20 Paradise Energy Solutions (717) 283-2021 direct _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
_______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
