I cannot speak for what if. I have seen CU & AL bolted in AL mechanical butt splices where someone did not torque it to spec. and it went to arcing. Both were a mess ; The butt splice was pitted / damaged and needed replacement, the AL cable melted and the copper cable did not. It the same amperage, but both were 1,600+watt arrays. But AL is softer and the strands are larger for the same size as CU wire.
I think that there was a greater safety factor in the CU. More strands, finer wires, a harder metal, therefore greater contact area on the AL mechanical butt splice. I have seen split bolts that were loose and you could pull the wire out easily and no melting or arcing. Thanks, Dana Orzel Great Solar Works, Inc E - [email protected] V - 970.626.5253 F - 970.626.4140 C - 970.209.4076 web - www.solarwork.com "Responsible Technologies for Responsible People since 1988" -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Dana Sent: Friday, July 23, 2010 4:24 PM To: 'RE-wrenches' Subject: Re: [RE-wrenches] AL wire with DC OG - Off Grid Thanks, Dana Orzel Great Solar Works, Inc E - [email protected] V - 970.626.5253 F - 970.626.4140 C - 970.209.4076 web - www.solarwork.com "Responsible Technologies for Responsible People since 1988" -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Richard L Ratico Sent: Friday, July 23, 2010 4:18 PM To: [email protected] Subject: Re: [RE-wrenches] AL wire with DC Dana, Thanks for the input. Excuse me please, "OG jobs" are? If the wire had been copper and didn't melt, but instead continued to arc, would the resultant heat have eventually started a fire? What type of splice was it? Does no one else use Al for DC? Here in rocky Vermont/NH, we use the same type aluminum URD cable for both AC and DC runs, but, always installed in PVC conduit, never direct buried. Haven't seen seen a problem yet. Dick Ratico Solarwind Electric --- You wrote: The problem with Al is that, IF there is ever a loose connection, & associated arcing, that it melts not like copper in the same situation which may arc but not melt. I have come in on OG jobs where Al was employed and found J boxes that were [sometimes wet] and had loose connections and the splice was charred/melted and the AL wire was not conducting & melted beyond use, directly at the splice. The rubber linemen's tape was charred and there was a direct short to the metal box which was at least grounded correctly. I tend not to use Al based on this experience. Thanks, Dana Orzel Great Solar Works, Inc E - [email protected] V - 970.626.5253 F - 970.626.4140 C - 970.209.4076 web - www.solarwork.com "Responsible Technologies for Responsible People since 1988" -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of R Ray Walters Sent: Friday, July 23, 2010 7:46 AM To: RE-wrenches Subject: Re: [RE-wrenches] calculating DC voltage drop I try to keep it in copper for DC, as I had always heard of trouble with Aluminum on DC. (True or Old Wrenches Tale?) We definitely go to Al on long AC runs, as its whats available, and the cost difference becomes remarkable. I've seen small cuts in Al, later corrode completely through the conductor.(AC run) I'm not sure what would happen it were DC. Probably depend on whether it was positive or negative, and which was bonded to ground? (either accelerate the corrosion, or act as cathodic protection?) R. Walters [email protected] Solar Engineer --- end of quote --- _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wren ches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrench es.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3023 - Release Date: 07/23/10 00:36:00 _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wren ches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrench es.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3023 - Release Date: 07/23/10 00:36:00 _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
