The electrical system is one of the most important components in a house because of the potential hazard faulty wiring creates. In research done by the Consumer Product Safety Commission, it was found that 1 out of 5 homes wired with aluminum had potentially dangerous, intermittent ‘hot connections”.
Aluminum wiring was used extensively in Canada from the mid 1960’s through the mid 1970’s. Initially, aluminum wiring was chosen for its low cost compared to the more expensive copper wiring. Some houses are wired completely with aluminum or copper. Others have a combination of both.
HOW TO RECOGNIZE ALUMINUM WIRING
Aluminum wire is not as good of an electrical conductor as copper, so a larger wire is used. For example, aluminum wire No. 12 has about the same ampacity as copper wire No. 14. The ampacity is the maximum current that a wire can safely carry. The outer covering of the cable will be marked about every 12 inches with the word aluminum or an abbreviation such as “ALUM” or “AL. Where aluminum wire is present, special service connectors must be used. Wall switches and receptacles should carry the marking “CU-AL”. This indicates that the equipment is suitable with aluminum wiring. This marking would also appear on circuit breakers. Electrical receptacles, wall switches and fuse boxes designed for use with copper wiring are not satisfactory for use with aluminum wiring.