I am considering buying a home with aluminum wiring. What do I need to know about this?
Aluminum wire was used in the 1960’s and 1970’s as an alternative to copper when prices took a sharp increase. There is nothing wrong with using aluminum wire, in fact if you bought a house just built it would most likely have some aluminum cable in it.
Aluminum is not quite as good of a conductor as copper but than copper isn’t as good as gold! Adjustments are made in conductor sizing to equalize the performance of aluminum conductors to copper and it is much cheaper. Now it is used mainly for larger cables in houses such as for the range and the panel feeders. We use a mineral oil compound on the wire to prevent oxidation. The utility company uses aluminum cable to bring power to your house.
Aluminum wiring most often fails at its point of attachment to the device.
Electrical devices used in conjunction with aluminum wire must be rated and UL listed for use with aluminum. If you were to examine the back of your large range outlet, for example, you would see a marking like: CU/AL meaning the device is rated and listed for use with copper or aluminum.
There are currently no 15 or 20 amp devices, such as switches or receptacle outlets that are rated for use with aluminum. There-in lies the problem but there is a solution. You will need an electrician for this and honestly the procedure isn’t cheap.
Many people negotiate the cost into the contract when buying a home with aluminum wiring. At the point of termination copper jumper wires must be attached to the aluminum wire and then to the switch or receptacle. Because of oxidation issues caused when joining dissimilar metals, copper to aluminum, special care must be taken in this process. There are UL listed wing-nuts available now that we use for this procedure. They are quite expensive but they are UL listed meaning that they have been tested extensively for use in this way and can be trusted.