Between approximately 1965 and 1973, aluminum was widely used for residential branch circuit wiring in Canada and the United States. Copper prices had spiked and aluminum was a cost-effective alternative. Millions of homes in the GTA and across Ontario were built or renovated during this period — and many still contain this original aluminum wiring today.
What's the problem with aluminum wiring?
Aluminum wiring itself isn't inherently dangerous — aluminum is used safely for large-gauge service entrance conductors in virtually every home built today. The issue is with small-gauge (15A and 20A) aluminum branch circuit wiring and its connections.
Aluminum expands and contracts at a different rate than the copper connections and terminals it was attached to. Over decades of temperature cycling, these connections loosen. Loose connections create resistance, resistance creates heat, and heat creates fire risk.
According to the U.S. Consumer Product Safety Commission, homes with aluminum wiring are 55 times more likely to have a fire hazard than homes with copper wiring, when connections aren't properly maintained.
How do I know if my home has aluminum wiring?
- Look at your electrical panel — aluminum wiring is silver-coloured (copper is orange-gold). Wires labeled 'AL' or 'ALUM' are aluminum.
- Check any exposed wiring in your attic or basement — aluminum is silver, not copper-orange.
- If your home was built between 1965 and 1973, there's a reasonable chance it has some aluminum wiring.
Remediation options
1. Full rewire (most comprehensive)
Replacing all aluminum branch wiring with copper is the gold standard. It eliminates the risk entirely. However, it's the most expensive option and requires accessing walls throughout the home. Best done during a major renovation when walls are already open.
2. Pigtailing with AlumiConn connectors (most cost-effective)
Pigtailing involves connecting short copper wire segments to the ends of each aluminum wire at every device and in every junction box. AlumiConn connectors are CSA-approved for aluminum-to-copper pigtailing — the most common remediation method in Canada.
If you're buying a home and the inspection reveals aluminum wiring, this is a legitimate negotiation point. Proper remediation is a known cost — use it to adjust the purchase price.
Safer Electric Team
Licensed Electricians · Toronto, ON
Our team of licensed GTA electricians writes these guides to help homeowners make informed decisions. Every article is reviewed for technical accuracy.