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Faunsdale, AL | My experience is it’s time and exposure. It can be heat from full load that causes the connections to expand and shrink a little resulting in lugs loosening over time. That will result in either corrosion and heating or just arcing. Not a bad idea to preemptively go over any aluminum cable connections and check for loosening or even loosen, apply protective grease like NOALOX and then retighten. Lots of connections here done without the grease in the past. Once the lug heats up and corroded a little, you can’t loosen or tighten it and it’s time for a new box if you can make the shortened wires work.
But, classic failure is a nick or scrape in insulation that’s exposed to weather. Years later wire fails and there’s a section of the aluminum that’s turned to powder. That’s what I’ve seen in triplex overhead wiring. Generally it’s pretty reliable and it’s all the power co has used for a generation or two, but it happens occasionally. Aluminum buried in conduit better be perfect or it’ll fail too. But usually the problem is at the terminations on each end.
Not really related except for the aluminum wire, but I’ve bought a set of jumper cables and seen a battery charger that was built with fine strand copper plated aluminum wire that did the same. The cables worked great for a while, but I let them get rained on in the back of the pickup and I think that sealed their fate. Couldn’t get any amps through them at all one day. Found a corroded crimp where the clamp was attached to one cable . Fixed that and applied NOALOX before recrimping using the opposite side of the clamp, so identical to original but with the protective grease for aluminum. Wasn’t long before I had done all 4 clamps like that and then it quit again. That time I found a section of powdered aluminum corrosion about 8 inches back from one end under what looked like perfect insulation. At that point I pulled the plug and threw them in the dumpster!
The battery charger was at the neighbors and I saw the crimp area of the one clamp was wrapped up with tape but didn’t think much about it. Attached it to the tractor battery but couldn’t get any amps to flow. Figured the batteries were stone dead (they were) so it would pick up over time. Came back next morning and batteries were still dead. Then I got out test light and couldn’t even get it to burn touching the clamps of the running battery charger! So I snipped off the whole taped up mess and sure enough the cables are copper plated aluminum! I recrimped the clamp back to the clean bright shortened cable using the other side of the clamp but I bet the only long term fix is going to be to replace with copper. | |
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Two wires to each leg feeding breaker box
