Why so many Edmonton homes have it
In the late 1960s and through much of the 1970s, copper prices rose sharply and aluminium became a common choice for the branch circuits in new homes. Edmonton grew quickly in those years, so many neighbourhoods built in that era have at least some aluminium wiring.
Aluminium is a good conductor and is still widely used today for service entrance cables and large feeders. The concern is with the small branch circuit conductors that feed your outlets, switches and lights, and specifically with how they were connected.
Thousands of Edmonton homes with aluminium wiring are lived in safely. The key is knowing you have it, using the right connection hardware and watching for warning signs.
What goes wrong at the connections
Problems almost always start at the ends of the wire, where it connects to a receptacle, switch, light fixture or splice. The wire itself, running through the walls, is rarely the issue.
- Expansion and creep: aluminium expands and contracts more than copper as it heats and cools, and slowly deforms under pressure. Screws that were tight can loosen.
- Oxidation: exposed aluminium forms an oxide layer that resists current.
- Mismatched parts: devices and connectors that were never designed for aluminium, or copper and aluminium joined without the right connector.
All of these increase resistance at the joint. More resistance means more heat, and heat is what can damage devices and start fires.
How to tell if you have it
You can often find clues without opening anything up.
- Age of the home: built or renovated between the mid 1960s and late 1970s.
- Cable jackets: in an unfinished basement or attic, look at the printing on the cables between joists. It may say AL or ALUMINUM.
- Labels: "AL" or "AL/CU" printed on devices can be a clue, but those markings are found on many devices and do not prove the house wiring is aluminium.
- Paperwork: a home inspection report or insurer may already have flagged it.
Removing a receptacle or switch to check the wire can disturb already fragile connections, and the box may be live. Leave inspection to a licensed electrician.
Warning signs specific to aluminium
The general electrical warning signs all apply, but in aluminium-wired homes pay special attention to:
- Faceplates on receptacles or switches that feel warm.
- Lights that flicker when nothing else has changed.
- Outlets or lights that stop working, then start again.
- A faint burning plastic smell near a device.
- Discolouration around a receptacle or switch.
Any of these on an aluminium circuit deserves a call the same day. Stop using the device and switch off the circuit if you can do so safely.
Your options for making it safer
There are three common approaches. A licensed electrician will look at your home and recommend the right mix.
| Option | What it involves | Good to know |
|---|---|---|
| Pigtail repair | At every device and splice, a short copper lead is joined to the aluminium with a connector specifically listed for aluminium-to-copper | Addresses the weak points without opening up walls. Parts must be the right type and installed correctly |
| CO/ALR devices | Replacing receptacles and switches with devices rated for aluminium | Only covers devices it applies to, not fixtures or splices |
| Rewiring | Replacing branch circuits with new copper cable | The most permanent fix. Often done in stages or during a renovation |
Cost depends on the number of devices and splices, how accessible they are, whether walls are open, and whether other upgrades like panel work happen at the same time. If you are already planning a basement renovation or whole-home rewiring, it is a good time to deal with aluminium circuits as part of the same permit.
Ordinary twist-on connectors not listed for aluminium-to-copper joints can make the problem worse. This is a job for a licensed electrician with the right materials.
Living with it day to day
Until your home has been assessed and any repairs are done, a few habits help reduce strain on aluminium circuits:
- Avoid running high-draw appliances like space heaters, kettles and hair dryers on the same circuit at the same time.
- Plug heaters and other big loads directly into the wall, never into a power bar or extension cord.
- Replace any plug-in device that feels loose in its receptacle, and stop using receptacles that no longer grip a plug firmly.
- Do not add dimmers, smart switches or new fixtures to aluminium circuits yourself. Many of these devices are not rated for aluminium.
- Keep a note of any device that has ever been warm, flickered or stopped working, so the electrician can start there.
Winter is when these circuits work hardest. Furnace fans, block heaters, holiday lights and space heaters all add up, so a fall check is a sensible habit in an aluminium-wired home.
Insurance and selling
Some insurers ask about aluminium wiring and may request an inspection or proof of remediation. Requirements vary from company to company, so ask yours directly.
If you are buying or selling, a written home electrical inspection report helps everyone understand what is there and what has been done. See our checklist for buying an older home.
Common questions
Is aluminium wiring illegal in Alberta?
No. Existing aluminium branch wiring is not illegal. The concern is how it is connected and maintained. Any new work on it must use materials rated for aluminium and follow the current code.
Do I have to rewire the whole house?
Not necessarily. Many homes are made safer with pigtail repairs using the right connectors at every device and splice. Rewiring is the most permanent solution and is often done in stages.
Is the big cable coming into my panel a problem if it is aluminium?
Aluminium service and feeder cables are common and acceptable when installed with the right terminations. The concern is mainly with smaller branch circuit wiring from that era.
Can I just swap my outlets for new ones?
Only devices marked for aluminium should be connected to aluminium wire, and the connections have to be made correctly. Have a licensed electrician do this work.
Codes and permit rules change and every building is different. For work on your system, talk to a licensed electrician and your local permit authority.