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_wiring/_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.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org