In recent years there has been an increase in the concern over the safety of aluminum wiring. In particular, purchasers or owners of homes built from the mid 1960’s to the late 1970’s with aluminum wiring are finding that many insurer’s will not provide or renew insurance coverage on such properties unless the wiring is inspected and repaired or replaced as necessary, and the work is inspected by the ESA (Electrical Safety Authority), and a copy of the certificate of inspection is provided to the insurer. In some cases the insurer may require replacement of the aluminum wiring with new copper wiring.
Many homes have a mixture of both aluminum and copper wiring.
Reported problems with aluminum wiring have been related to the overheating and failure of aluminum wiring terminations. This is due to the tendency of aluminum wiring to oxidize, and aluminum’s incompatibility with devices designed for use with copper wiring only. Aluminum has a higher rate of expansion than copper wiring, which can lead to loose connections, arcing and melting, eventually fire. Ware cover plates or discoloration of switches or receptacles, flickering lights or the smell of hot plastic insulation may be evidence of poor or improperly made connections.
All homes are wired differently and must be assessed on an individual basis. The Electrical Safety Authority recommends that the homeowner hire an authorized electrical contractor that is knowledgeable in the approved methods for working with, and repairing aluminum wiring.
Replacing all the receptacles and switches in the home, with ones that are rated for aluminum wiring (not available at any BIG BOX stores), and treating all other connections at light fixtures and junction points with an antioxidant, and replacing wire connectors with ones that are rated for aluminum.
It is interesting to note that the acceptable wire connection methods that are used in Ontario and Canada as well as many of the US States are not acceptable in other US States.
This probably poses a policy issue with International Insurance Companies.
The reality is however – that the Electrical Inspection Department of whatever jurisdiction has the final say as to what is acceptable.
Aluminum in itself is not a dangerous material to be used for wiring – the terminations and connection points are where the trouble begins.