June 04, 2017, 12:27 PM
slosigElectrician question: How to correctly connect suspected Al to Cu wires?
Fixing an fertilization injection system (12v, but pulls some HP). Sales rep came up with higher flow pumps as the originals weren't getting the job done. Manufacturers rep said it would be fine but he'd have to program the pump drivers to not run them any harder than 70% so as to not hurt the drivers. On the initial test run smoke departed the enclosure. On inspection, they had wired with 18-3, terminated the ground where it landed on a j-block, and cut it off on the other end. Manufacturers rep came out, realized he'd screwed up the programming and fixed that, but said it would need to be rewired throughout the path to the pumps (you think?). I did that with 12 gauge. When attaching to the 14awg pump pigtails, noticed that the stranded wire was finer, silver in color, and doesn't feel like copper. I'm guessing it isn't copper wire with the original strands individually coated, so I'm guessing aluminum. The bag of larger wirenuts I bought said on them Cu/Cu only.
My first thought was just to solder all ten connections, but then it occurred to me that a better plan would be to ask my (much more knowledgeable) invisible friends to make sure that isn't a bad idea.
Thoughts? Better way to solve the problem?
Thanks much!
-Nick
June 04, 2017, 12:33 PM
Skins2881Likely tin plated Cu. I've never seen small gauge stranded AL.
Cut the wire at a 45° angle you should be able to see Cu.
June 04, 2017, 12:53 PM
Skins2881quote:
Originally posted by slosig:
Awesome, Thanks much!
If you want to be safe, bring three of boxes of
these with just in case. That way you can get it done either way. They can be used for Al/Al, Al/Cu, or Cu/Cu. But I really think it's extremely unlikely to be Al, never hurts to be overly prepared, and HD takes anything back.
June 04, 2017, 02:03 PM
slosigGood plan, but Home Despot is a half hour round trip, so I'll try to verify the wire first. Thanks much for the info and suggestion!
June 04, 2017, 02:06 PM
stoic-oneI use a LOT of tinned wire, if it is even remotely flexible no matter the stranding, it's not aluminum...
June 04, 2017, 04:13 PM
slosigSkins2881 & stoic-one you're both absolutely correct. The pigtails on the motors barely reached into the j-box and the strands were so tiny that I don't know if I'd have it on a cut end even if I could spare the wire, so just scraped a stripped end with a pocketknife. Got that glint of copper, so good to job. Thrilled to have that job done, thanks a million for your help!
I learned something too. The strands were so tiny I didn't think they be individually plated before being wrapped into the stranded wire, but they obviously were.
Thanks again!
-Nick
June 04, 2017, 05:24 PM
FRANKTquote:
I learned something too. The strands were so tiny I didn't think they be individually plated before being wrapped...
Then you'd be blown away by the Litz wire that was used as transmission line for a VLF transmitter I worked on at NavRadTransFac Annapolis in the early 70s. It's amazing what some of the wire/cable manufacturers can do.