Connecting 12 gauge solid copper to 18 gauge stranded aluminum

[tomtheelder2020]

Connecting a new bathroom fixture with 18 gauge aluminum wire to the original (1951) household wire that is pretty stiff so I am guessing 12 gauge. I connected the previous fixture (which had about the same gauge aluminum wire) just using wire nuts. After something like 10-15 years, both compact fluorescent and LED lights started to flicker and I figure that connection is the most likely culprit. I am replacing the whole fixture at wife's request. Surprisingly, Youtube not helpful on how to connect these very dissimilar wires. What do you recommend - other than solder*?

*which I have never done and don't want to make first try while on a step-stool holding a fixture above the vanity.

 

[Snoonyb]

Google is your friend, nolox is a method.

 

[bud16415]

Are you sure the wires are aluminum? I have never seen a light fixture wired with aluminum. Sometimes the ends of the striped wires are (tinned) with solder and that could be mistaken for aluminum. Can you post a photo?

 

[user 4883]

Are you sure the wires are aluminum? I have never seen a light fixture wired with aluminum. Sometimes the ends of the striped wires are (tinned) with solder and that could be mistaken for aluminum. Can you post a photo?

Right, if the fixture is new, I highly doubt the wire is aluminum. Either tinned with solder or tinned with silver. You could always cut the exposed wire and strip back some insulation to reveal it's true composition.
And yes, nolox is the preferred method to marry to aluminum to a dissimilar wire type.

 

[tomtheelder2020]

Well, it sure looked like aluminum to me. Each individual strand was aluminum color - until I scraped with a utility knife and suddenly copper was showing. This is why I like to check with people who know more than be before I barge ahead. Thanks.

Is there any reason to NOT use a butt connector with such different sizes?

 

[bud16415]

I would just twist and wire nut.

 

[tomtheelder2020]

Bud, I know wire nut is the most common method but is there any problem with using a butt connector, particularly since the wire sizes are so different? I happen to have a bunch of them inherited from father-in-law.

 

[bud16415]

I guess you could do that as long as it’s inside a box.



For me I would rather be able to take it apart down the road and not have something crimped on.

The new modern wire nuts bind down on different size wires great as long as you get the right one for the size and number of wires you have. I always give each wire a tug when I’m done that will show you if you have something not holding.