Aluminum Wiring

Home inspection today revealed that the house is wired with aluminum wiring. It’s a known potential fire hazard so merits more research. There are lots of websites out there but this is the one that the electrician (Electrical Contractors and Design) that I talked recommended regarding Recognizing Aluminum Electrical Wiring.

There are different fixes for the problem but the “best” system, made by Tyco, attaches a copper wire to the aluminum with a special tool. Every outlet, switch and fixture throughout the house has the Amp Copalum applied to it.

One Comment on “Aluminum Wiring

  1. I’m an electrician with 25 years experience in the trade, so I’ll throw in my 2 cents here – see what you think.

    Nothing’s wrong with aluminum wiring, strictly speaking. It’s a fine conductor, widely used by the utilities for their distribution networks. And for good reason – it’s less expensive, much lighter in weight (meaningful to those who hang their wiring on poles), and every bit as good at carrying current as copper wire.

    But you have to terminate it correctly. If you don’t, it will fail – and that means heat, and possibly, a fire.

    Upon exposure to air after stripping away the insulation, aluminum wire begins to corrode within a few minutes by forming a thin coating of aluminum oxide. The aluminum oxide coating is fairly high in electrical resistance, so passing current through it will generate heat. This happens at those places where the wire makes its connection (“termination”) to an electrical device – but nowhere else along the conductor, unless the insulation has been pierced.

    Therefore, making proper terminations is the key to a safe aluminum wire installation. I agree that the method shown in the “Amp Copalum” is about as good as you can get, because if DONE PROPERLY it eliminates contact with the air at the point where the aluminum wire mates with the copper wire. Immediately upon stripping the aluminum and exposing it to air, you must apply an anti-corroding grease to it, thus preventing aluminum oxide from forming. The connector which crimps the copper and aluminum wire together must also be filled with the same grease. crimping the connector on mashes the two wires together in the complete absence of air, forming an anaerobic connection which should last for the life of the house.

    This is pretty much what utility linemen do when they make their connections.

    Unfortunately, when aluminum wiring was introduced into housing construction (about 1968, I think), the residential electricians weren’t trained in making aluminum terminations, but instead made their terminations the way they always had when using copper – which made no provision for eliminating the presence of air at the point of contact. Therefore, there were fires.

    Aluminum wiring in residential construction is still permitted under the electrical code – because it’s perfectly safe DONE PROPERLY. I’ll bet it would even be less expensive than using copper wiring, even allowing for the additional time required to make the terminations the right way. The issue is one of quality craftsmanship, not quality materials – that is to say, a commitment to doing a job right rather than quickly. And whether for good or ill, that kind of commitment receives a greater commitment in industrial/commercial electrical work than in residential.

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