How to tell if you have it
Look at cable jackets in an unfinished basement or at the panel: aluminum cable is often marked "AL" or "ALUMINUM". At a switched-off outlet, the conductor itself looks dull silver rather than copper. If you're not sure, an electrician can confirm in minutes.
Why connections are the issue
Aluminum expands and contracts more than copper and oxidizes at the surface. Over years of heating and cooling, connections at outlets, switches and splices can loosen, increasing resistance and heat. The wire running through the walls is usually fine — it's the terminations that matter.
The two fixes
- Pigtailing (remediation): each aluminum termination gets a short copper lead joined with a connector approved for aluminum-to-copper connections. Devices are then connected to copper. Far less invasive and much cheaper than rewiring.
- Replacement: rewiring the affected circuits with copper. It makes sense when walls are open for a renovation anyway.
Typical costs
Whole-house pigtailing in a typical GTA home usually runs $1,800 – $4,000, depending on the number of devices. Replacement is quoted per circuit and depends heavily on access.
Insurance
Some insurers ask for confirmation that aluminum wiring has been inspected or remediated by a licensed electrician. After remediation you receive the ESA Certificate of Acceptance and a letter describing the work.
Warning signs
- Warm or discoloured cover plates
- Flickering lights not explained by the bulb
- A burning-plastic smell near an outlet or switch
If you notice any of these, stop using that circuit and have it checked. See also our electrical inspections.
Quick questions
Is aluminum wiring illegal in Ontario?
No. Existing aluminum branch wiring isn't illegal, and many homes still have it. The concern is the terminations, which is why remediation focuses on connections.
Can I just replace the outlets myself?
Standard devices aren't rated for aluminum conductors. Remediation uses connectors approved for aluminum-to-copper joins and should be done by a licensed electrician with a permit.
Does pigtailing need a permit?
Yes — it's electrical work and should be filed with ESA, which also gives you the certificate your insurer may ask for.
