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Most home wiring is copper, and you're not supposed to connect it with aluminum wire using a wire nut (push-in connectors are fine.) The reason being is the aluminum will apparently corrode. Is it safe to connect aluminum wire directly to the terminal screw in an outlet, or do you need to use push-in connectors to connect to a copper wire and then connect that?

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    Where did you get that? Push-in connectors aren't ok for aluminum. They're not even all that great for copper. – Harper Nov 29 '18 at 8:18
  • What actual situation are you facing where you are wondering about connecting aluminum wire directly to the terminal screw in an outlet? Do you have aluminum wiring in your house or does someone you are helping have it? There are receptacles labeled CO/ALR which are designed to accept aluminum conductor #12. I have aluminum wiring and I have had some of these CO/ALR receptacles (with #12 and #10 aluminum) in service for 35 years with no problems. You cannot expect good results with aluminum wire connected directly to standard receptacles. I also have many receptacles "pigtailed" with copper. – Jim Stewart Nov 29 '18 at 12:10
  • What kind of aluminum stranded wire are you contemplating connecting to a receptacle? Is this a 120 V receptacle or is it a receptacle for a dryer or an electric range? There are 240 V receptacles which are listed for direct connection with stranded aluminum wire. There will be a statement on the receptacle to the effect "approved for Cu or Al solid or stranded". I have to admit that in the one instance when I installed a NEMA 14-50 receptacle (or its predecessor) I did not like the way the clamping screw splayed out the stranded aluminum conductor. – Jim Stewart Nov 29 '18 at 12:41
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You're supposed to connect to aluminum wire using connections listed for use with aluminum wire. There is nothing magical about one style of connector vs. another, you can't say "all X type are ok for aluminum", they have to be individually listed for aluminum.

You also cannot put aluminum wire on common receptacles, get your money back from whoever taught you that, it's dangerously wrong.

There are aluminum wire nuts, but they aren't reliable. The gold standard for pigtailing or splicing aluminum and/or copper wires is **alumiconns*, a mini verson of a mains lug. Like most lugs, Alumiconns are made of aluminum. Turns out aluminum lugs work fine with both wires, copper lugs don't.

Regardless, you don't need to pigtail. You can directly attach aluminum wires to a receptacle with a CO-ALR rating for its connections, meaning it is compatible with both copper and aluminum. These cost a few dollars more, and have weird gray metal on their terminations.

  • thanks for this. i thought push-in connectors were fine because the copper and aluminum wires never actually touch? – Walrus the Cat Nov 29 '18 at 21:11

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