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Question:

connecting aluminum and copper wires.?

This is not for around the house. It is for my lab. I am pretty sure these one wires are Aluminum, but I need the connector they were made with and the power cable is copper. Would it be okay to still try to join the two.

Answer:

yes but use wire nuts
different metal heat at a different rate use oxigaurd and wire nuts
They can be joined but only through a suitable device marked specifically for aluminum to copper connections. See website below.
The main problem with aluminum wiring is cold creep. When aluminum wiring warms up, it expands. When it cools down, it contracts. Unlike copper, when aluminum goes through a number of warm/cool cycles it loses a bit of tightness each time. To make it worse, aluminum oxidizes, or corrodes when in contact with certain types of metal, so the resistance of the connection goes up. Which causes it to heat up and corrode/oxidize still more. Eventually the wire starts getting very hot, the insulation melts or it damages the fixture it's attached to, and possibly even cause a fire. Anything attached to aluminum wiring should be rated for it. It will be stamped with Al/Cu or CO/ALR. Wires should be properly connected (at least 3/4 way around the screw in a clockwise direction). Connections should be very tight. Any connections using push-in terminals should be redone with the proper screw connections. Connections between aluminum and copper wire need to be handled specially. The NEC requires that the wire be connected together using special crimp devices, with a special anti-oxidant grease. The tools and materials for this are expensive - not practical to do it yourself unless you can borrow the tool. Good luck.

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