Aluminum wiring is still used today in many applications.  All of the power company’s lines are aluminum.  Copper is too heavy to run overhead and too expensive to use in the mass quantities that they use for wire.  Large feeder wires for 240-volt items are typically run in aluminum as well to help save costs.  The issues with aluminum wiring stemmed from their use in smaller branch circuit wires like the ones that feed your outlets, switches, and light fixtures.  Even then, the problems don’t occur in the walls.  They happen at the connection points of your outlets, switches, and lights.  Aluminum will expand and contract more than copper will with use.  As your electrical system sees more use over time, the aluminum connection points will work themselves free from the outlets, switches, and light fixtures they are connected to and cause loose connections.  These loose connections can lead to small problems like simple outages all the way up to larger problems like fires.

Aluminum wiring on small branch circuits was only installed during the Vietnam War.  The copper was being rationed for bullets. So if your house was built in the 50’s or before, you aren’t going to have aluminum wiring in it.  If it were built in the mid-70’s or later, you wouldn't have aluminum wiring either.  If a remodel happened during the Vietnam era, you might have a portion of the house wired in aluminum.  

Rewiring to Copper Wiring
There are a number of ways to remedy aluminum wiring.  We get a lot of requests to rewire the whole house when aluminum wiring exists.  Not only is this the most expensive way to remedy the situation, but it will also cause other issues like a bunch of sheetrock repair.  We typically won’t take on a whole house rewire project, but for numbers’ sake, we ballpark around $10 per square foot to rewire a house.

Co/ALr Outlets
Co/ALr rated outlets and switches are another option that we get requests for from time to time.  They are devices that are rated for copper and aluminum connections.  The screws that terminate the wires are a little larger to help press down on more of the conductor.  This connection is supposed to squeeze everything a little better, but at the end of the day, you’ve still got aluminum exposed to free air and with use, will work itself free.  It is recommended that you go through all of your connections once per year and tighten them again.  This method is not a permanent install due to the additional work required every year.  There also aren’t any tamper resistant Co/ALr rated outlets that we are aware of.  All outlet replacements are required to be tamper-resistant.  The same holds true for GFCI receptacles.  There are no Co/ALr rated GFCI’s that we are aware of so we can’t install them where needed.  Co/ALr rated devices are no longer a viable solution to remedy aluminum wiring.

Pigtailing Using Alumiconn, Copalum, and Purple Wire Nuts
The last option is pigtailing the aluminum wires.  This option is taking the connections at your outlets, switches, and light fixtures and joining in a copper conductor with the aluminum ones.  A UL listed connector must be installed for this application for it to be a legal install.  This joint is then pushed to the back of the box, and the copper wires are now attached to your outlets, switches, and light fixtures.  There are a few different types of connectors available: Alumiconn, Copalum, and purple wire nuts.  Alumiconn is a type of terminal block that terminates each wire separately.  It is rather large and harder to work with.  Copalum is a cold welding crimp that uses special crimps, a crimper, and heat shrinks to seal the connection.  You have to be certified by their manufacturer with a class and the costs for the tools and materials are higher than the other methods.  The last method is purple wire nuts.  They have a higher heat rating than regular wire nuts and have an antioxidant built in to prevent the copper and aluminum from oxidizing when mixed together.  

You can find pros and cons to each method depending upon what website you look at and who is sponsoring that page.  We have used all three, and each one is a perfectly viable solution to the problem.  The methods in which they are installed is what determines how effective they are.  We prefer to use purple wire nuts because they are simple to install, take up less space in the already small boxes, and don’t require any specialized training from manufacturers.  They are the most cost effective solution to remedy aluminum wiring.  We ballpark around $3/square foot to pigtail whole house, but we will need to get a count of everything and see what type of new outlets and switches you would like installed.

When we pigtail, we do provide new tamper resistant outlets, new switches, GFCI’s where they need to be, and plates for everything.  We are also required by code to install arc fault protection on all of the circuits.  Depending upon the situation, that may require breakers or arc fault devices.
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Aluminum Wiring