The house I purchased last year was constructed in 1972. A neighbour whose house is the same age told me I have aluminum wiring that can be a fire hazard. Is this true? If so, is there anything I should be doing to avoid problems?

Many houses constructed between 1964 and 1978 came equipped with cloth and plastic sheathed aluminum wiring. You should have an electrician confirm this because aluminum wiring can be easily mistaken for an older type of solder dipped copper wiring. Here’s a tip. Aluminum wiring can be distinguished by the bare aluminum grounding conductor and the word ALUMINUM or ALUM or AL on the sheathing.

Aluminum wiring was introduced in the 1960’s because it was a less expensive alternative to copper wiring, even though larger wire gauge sizes were required and it was not as good a conductor as copper. Some problems associated with aluminum wiring are that the wire tends to creep out from under the terminal screws, the wire can oxidize reducing conductivity, and the wires can be easily damaged during installation. Several house fires were attributed to this wiring as a result of these deficiencies. Industry then responded to these concerns by designing connectors, receptacles and switches better suited to this wiring. Not all houses were retrofitted with this hardware so you should confirm that your receptacles, switches, connectors and fixtures are labeled CUAL and / or CO/ALR. The latter designation was introduced in the early 1970’s and used tin-plated terminals. This hardware more effectively controlled over-heating problems than the earlier CUAL hardware.

As well, if your home is equipped with aluminum wiring you should check for aluminum compatible equipment at the main panel. First, you or your electrician can check that the panel and circuit breakers have the aluminum designations (CUAL). There are even specially designed aluminum wire twist-on connectors, which continue to create controversy concerning their safety.  These wire nuts are not easily identified, so again, consult your electrician. In the main panel all larger stranded wires in contact with terminals should be coated with an anti-oxidant paste to prevent aluminum oxide from forming where the aluminum comes in contact with the air.

If you have aluminum wiring here are a few tips. Watch for signs of overheating especially at receptacles that are used for large demand appliances like clothes dryers, hair dryers and portable heaters. Have your local electrician do a detailed inspection, including a review of circuit wiring for loose wires at terminals. In the big picture, aluminum wiring can be safe if it has compatible receptacles, switches and fixtures and the wiring is maintained and serviced regularly.