How do I identify aluminum wiring in my home?

Aluminum wiring can be identified by a few key visual and documentary clues — and knowing whether you have it is an important safety step for any Ottawa homeowner.

Aluminum wiring was commonly installed in Canadian homes built between approximately 1965 and 1978, when copper prices spiked and aluminum became a cost-effective alternative. If your home falls in that era, there's a reasonable chance you have it.

Check Your Electrical Panel First

The easiest starting point is your main electrical panel. Open the door (not the inner cover — leave that to a licensed electrician) and look at the wires connecting to your breakers. Aluminum wiring is silver-colored, while copper wiring is orange-brown or reddish. You may also see the letters "AL" printed directly on the wire jacket, which is a definitive identifier. Some wires will also be labeled "ALUMINUM" in full.

Look at Outlets and Switches

If you're replacing an outlet or switch (with the power OFF at the breaker), look at the wires connected to the terminals. Again, silver-colored wires indicate aluminum. You might also notice the outlet or switch itself is stamped "CO/ALR" or "AL/CU" — these markings mean the device was rated for aluminum wiring connections, which is a strong indicator the home was wired with aluminum.

Check Your Home's Documentation

Your ESA Certificate of Inspection or original building permits may reference the wiring type. Home inspection reports from when you purchased the property often flag aluminum wiring as well. If you have a pre-1978 home and no documentation, assume it's worth having a licensed electrician take a look.

Why It Matters

Aluminum wiring itself isn't illegal, but it requires specific handling. Aluminum expands and contracts more than copper with temperature changes, which can cause connections to loosen over time. Loose connections create heat and arcing — a leading cause of house fires. Insurance companies in Ottawa increasingly require either remediation or a certificate from a licensed electrician confirming the wiring is safe before they'll provide coverage.

The two accepted solutions in Ontario are:

• Pigtailing — splicing short copper leads onto each aluminum wire at every connection point using approved connectors (CO/ALR rated)


• Full rewiring — replacing all aluminum wiring with copper

Pigtailing typically runs $150–$300 per outlet/connection in the Ottawa market, while whole-home rewiring can range from $8,000–$15,000 depending on home size.

What To Do Next

If you suspect or confirm aluminum wiring, don't panic — but do act. Have an ESA-licensed electrician inspect the system and assess the condition of all connections. This inspection will also help you understand what your insurance provider requires. Electrical Ottawa offers assessments for aluminum wiring situations, and all work is done to OESC standards with proper ESA permits.

For other renovation trades you might need during a rewiring project, vetted contractors are also available through the Ottawa Construction Network at ottawaconstructionnetwork.com.