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My house has aluminum wiring, which from what I understand isn't recommended any more. How do I replace a plug or switch since the new unit only takes copper wiring?

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Wow, I've never heard of aluminium wire being used in a house before. en.wikipedia.org/wiki/Aluminum_wire –  Matt Jul 7 '13 at 21:45

7 Answers 7

up vote 15 down vote accepted

There are two ways to do it:

  • Use CO/ALR switches/receptacles: these are specifically designed for aluminum wire. They have "CO/ALR" stamped on them somewhere. When you connect the wire, use a paste like Noalox (box stores sell it).

  • Use a pigtail connection: Sometimes it is not possible to find CO/ALR switches with the function or style you need. You can use a copper wire to connect to the switch itself as usual, and then a #63 wire connector to connect the copper wire to the aluminum one. Here is a picture of a 3-way dimmer switch I installed using this method:

    alt text (apologies for fuzzy picture)

    Note that you do the same thing with switches that have wires coming out of them already (like most dimmer switches do) or any other fixtures.

    enter image description here

In either case:

  • Connect with #63 wire connectors.
  • Use the anti-oxidant paste on the wire and any other connections involving aluminum (apply to the wires before you screw on the connector).
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Hey @gregmac your picture is no longer available. Are you able to re-upload it? –  Steven Jul 7 '13 at 21:49
According to the CPSC (Consumer Product Safety Commission), "CO/ALR devices must be considered, at best, an incomplete repair" that's only intended "as an emergency, temporary repair of a failed aluminum termination." Though less detailed, the answer below by @Jerr seems to be the safest method for dealing with aluminum wiring. See cpsc.gov//PageFiles/118856/516.pdf for more information. –  kevinmicke Mar 14 at 19:43

Here's what I did in my house, based on internet research and asking my Dad, a construction superintendent.

  1. Buy some wire nuts made for multiple types of wire and some anti-corrosion compound (usually available in the same area of the hardware store).
  2. Take some copper wire and twist it together with the aluminum wire.
  3. Put the compound on the wire and some inside the wire nut.
  4. Twist the wire nut onto the wire twist you made.
  5. Use the new copper end to connect to the new plug/switch.
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Very important safety note for the above: I believe you need to put the corrosion compound on BEFORE you twist the wires together. This prevents bimetallic corrosion between the two different types of wire, which would lead to higher resistance and a fire. Just smearing it on after you've already joined the wires is not enough. –  Karl Katzke Aug 15 '11 at 1:14
While that will prevent corrosion, won't you still get the separation caused from the heat generated between the copper and aluminum expanding? –  Zach Aug 18 '11 at 1:09
If you need to connect copper to aluminum, do not directly twist copper with aluminum. The two will eat at each other, and resistance and heat will increase. The only way to splice copper to aluminum safely is using a device listed for that use. Others here mentioned a wire nut that you can safely use instead. –  Jeremy W. Sherman Jul 13 '12 at 21:48

I am a licensed electrician in Connecticut. My own condo has aluminum wiring, I highly recommend the alum.con connectors because they are homeowner friendly. Two methods are presented:

  1. a special torque screwdriver (recommended)
  2. a set of specific instructions for the number of turns on the copper side/aluminum side.

These connectors are quickly becoming accepted by major insurance companies. Their downside is price: approximately $2.00 each, and figure three per outlet if you choose to do the grounds as well.

Also they are a bit larger than standard wire nuts adding a bit more difficulty for wire and device room in a existing device box. They appear to be code compliant in most cases for cubic inch capacity.

I have installed them in my home and neighbors. The biggest issue with aluminum wiring arc issues are exterior walls that are poorly insulated and major temperature changes occur over the years exaggerating the expansion/contraction issues. Hope this helps.

Do not use the Ideal purple wire nuts; I've seen too many melt downs; it's a bad product.

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I discovered I have the same issue here. My research has found that aluminum wiring is UNSAFE, and you need to be very careful about what you do. The two options are:

  1. Replace the wiring. This is not something that would be safe to do on your own (you really should get a licensed contractor), and looks to cost several thousand dollars (like $8000+ for a 1600 sq ft home).
  2. Use AlumiConn. This stuff is actually approved to be used for aluminum to copper connections (the other pigtails mentioned here are NOT), and you can get a free sample to try it out. There's another thing, called COPALUM, but it's not really something you can DIY. Wikipedia has some good information on this.

I'll update when I actually get my sample AlumiConn connector to see if it's a viable option. The safest option would be to get a licensed electrician to rewire the house with copper, since the aluminum connections are inherently dangerous (and you will probably find other issues, such as bad breakers, 3-wire 240V instead of 4-wire, and a poorly labeled breaker box like I did). I've had receptacles in my house spark and connections melt because of the aluminum, so please take this seriously.

Edit 1: There's also more information about aluminum wiring from the CPSC (PDF) (Consumer Product Safety Commission).

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"since the aluminum connections are inherently dangerous" How so? Isn't the only danger when you mix them with copper or other non-approved components? –  Zach Aug 18 '11 at 1:11
You still have the problem of oxidation. When the connection oxidizes, it increases resistance, which ultimately means heat. I'll update my post with a link to the CPSC document on aluminum wiring. –  Jerr Aug 20 '11 at 19:46
The main issue with the aluminum conductor is that aluminum expands more than copper when heated. This can cuase loose connections which can lead to arcing at the point of connection. –  RSMoser Nov 4 '11 at 16:01

Just buy the ALR rated outlets and switches. You can pigtail but I don't like that as you now have 2 connections instead of one and you bend the wire more stuffing all that into the box. I have 35 yr old alum wiring. My wiring is in great shape. Replaced several outlets that needed to be replaced. They had the classic alumnimum connection issues. Connected properly there is no problem with aluminum wire. I remember when it came out the industry was publishing all sorts of propaganda to sell ALR as the next big thing. Popular mechanics did a big piece saying we'd never use copper again. Now they are selling $50 "special" cold weld connectors. Its all a big friggin joke and a $ machine. A good connection will remain in place for decades no matter how many hot/cold cycles it goes thru. A bad connection may very well have problems.

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You should probably talk about what a proper connection is. –  Chris Cudmore Mar 27 '13 at 13:01

My parent's house has aluminum wiring. You can either search for CO-ALR switches and plugs which take aluminum wires or get the paste as you said and wire them together. The paste is important, otherwise the wires corrode and start rubbing/sparking .... bad mojo from there.

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To my knowledge, this insulated 3 port splice connector is the safest product on the market right now. Unfortunately, I don't know who actually makes it or what it's called- just what it looks like. NSi Industries (Tork) makes something similar (their IPL series), but I'm not sure if they make really small ones like you need.

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