If the house does burn down my wife will be so pissed at me. Anyway, after 14 years the control panel on our electric wall oven has crapped out and they don’t make replacements, so order a whole new oven. While waiting for delivery I pull the old oven and disconnect the wires and find to my surprise that the oven supply cable is aluminum (6 ga, 40A circuit). It was attached to the copper wires of the oven using what looks like standard wire nuts, with anti-oxidant compound liberally applied. Ground and common from the oven were both attached to the bare stranded lead of the supply cable. I’ve done what searches through this site that I can figure out and I’ve found many cautionary tales about joining Al to Cu, but not exactly how to do it safely. Was the original job done to best practices? Can I tackle this? My impression of the original wiring work (1994) is that the electrician was very cost-conscience but not dangerous. I’ve done a lot of small jobs around the house, adding or moving outlets and I’ve found that he used the $0.29 variety with wires pushed into the little holes in the back. I always replace them with the expensive $5 ones using pigtails clamped under the screws. Can I safely attach the Cu wires from the new oven to the Al supply wires? Do I do exactly as the original installer did? Are better techniques now available?
Your suggestions are very much appreciated.
Replies
I believe you are saying that the house wires are aluminum, and the wires from the over itself are copper.
You ought to get a Sparky to look at it. It is possible that the wires are too small to begin with. There is also the issue of needing a separate ground wire today - and that has to be copper. Your new oven should be hooked up to four wires, not just three.
Wire nuts are not a proper connection - not even the purple ones. A different type of connector, one that has a separate set-screw for each wire, should be used. The problem is, not many junction boxes have enough room for these connectors.
the problem with copper and alum, is they contrast at different rates so they will come loose.as long as they stay tight, no problem.
There's a bit more to the issue than that ... and even the experts have differing opinions. Yet another reason to have someone look at it in person.
My understanding is that solid alum was the problematic wiring (mainly 15 & 20 A in my area) but stranded alum is ok because the stranding nature minimizes the expansion contraction which was one of the basic problems (the other being limited bending ability of the earliest alum)
But, as said, check with an electrician ... s/he's got insurance to give advice.
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have you got room for a plug and box? buy a plug rated for al [i think all the big plugs are]wire it in a box,then put a plug on your stove pigtail and your covered with no questions.
i thought you had to run 4 wire when you ran new wire. the old 3 wire is ok as long as it's not being replaced with 3 wire? larry
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