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A couple years ago I inherited a reading lamp my Grandfather gave my Grandmother back in the 40s. It was functional, except the 3-way rotary switch needed to be replaced. The new switch had copper strand wiring, whereas the lamp's wiring was aluminum strand. Now I'm hearing it's not advisable to mate copper to aluminum. Too late, I already did. Using butt connectors. Am I in for problems?

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  • Not an answer, bc I’m certainly no electrician, but I can tell you I had a fire at my house because someone connected copper and aluminum wiring in a junction box that ultimately fed my laundry room (with a dryer, obviously.) The electrical inspector (an 80 year old guy) was rather displeased to have to come condemn my electrical panel at 9:30 pm on a Saturday night because of mixed metals. – Jax Nov 6 '19 at 14:51
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    Are you sure it's aluminum and not tinned copper??? Maybe include a picture. – JACK Nov 6 '19 at 14:54
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    Aluminum cost about $50 a pound back then because they hadn't prefected modern smelting methods... so I seriously doubt it was aluminum wiring. When they needed lots of wire for uranium enrichment at Oak Ridge, they raided the Mint and got silver instead of aluminum. Maybe it's silver! J/K, it's zinc plating on copper. – Harper - Reinstate Monica Nov 6 '19 at 15:00
  • Hello, and welcome to Home Improvement. Interesting question, but we'll need more info. And, you should probably take our tour so you'll know how best to participate here. – Daniel Griscom Nov 6 '19 at 15:13
  • Not certain it was aluminum. Silver-gray, rather than a copper color. Sadly, I have no photo of the bare wire. Though I just found a photo I took of the back of the switch so I could show it to the counter guy at electric supply. Says Leviton 3A.125 VIA25OV CAT. 573 – Knucklehead Nov 6 '19 at 15:59
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I doubt it was aluminum wiring , in fact silver or tinned copper is more likely for fixture wire , butt connectors would work ok for either of the 2. If aluminum corrosion may have already started. I would check for signs of thermal stress at the connectors. I actually have run into silver several times because silver was available at times when copper was not but including solid silver buss bars . I have never seen aluminum fixture wire. Note tinned copper looks just like aluminum but aluminum is brittle and just a bend or 2 it starts cracking and breaks. But I doubt it is aluminum.

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  • Definitely could be silver.. – JACK Nov 6 '19 at 21:53
  • We were demoing an old mill built in the 40’s the millwright’s were tossing the buss bars in the aluminum bins, it did not sound like aluminum so I thought it was tinned copper nope solid silver got a huge bonus for that save over 100 lbs in that small load center. – Ed Beal Nov 6 '19 at 22:38
  • You need to write a book. you've got some great stories. – JACK Nov 6 '19 at 22:52

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