The Electrical System: Aluminum Wiring

The electrical system is one of the most important parts of your home—it keeps everything running and can pose serious risks if not properly maintained. Faulty wiring, for example, can be a hazard. Research by the Consumer Product Safety Commission found that 1 in 5 homes with aluminum wiring had potentially dangerous, intermittent “hot connections.”

What’s the Story with Aluminum Wiring?

Aluminum wiring was commonly used in Canadian homes from the mid-1960s to the mid-1970s. It was an affordable alternative to copper wiring at the time. Some homes are wired entirely with aluminum, others with copper, and many with a mix of both.

How to Spot Aluminum Wiring

Aluminum isn’t as good a conductor as copper, so the wires are thicker. Look for markings on the outer covering of the wire about every 12 inches. You might see words like “Aluminum” or abbreviations like “ALUM” or “AL.”

Where aluminum wiring is present, special connectors and compatible switches and receptacles must be used. Look for “CU-AL” markings on outlets, switches, and circuit breakers—these are designed to work with both copper and aluminum wiring. Standard fixtures for copper wiring aren’t safe for aluminum wiring.

Warning Signs of Aluminum Wiring Problems

Here are some things to watch out for:

• Very warm switch or outlet cover plates.

• Switches or outlets that suddenly stop working.

• Smoke near electrical outlets or switches.

If you notice any of these signs, it’s time to call a professional!

Preventing Problems

Aluminum wiring can be just as safe as copper if installed and maintained properly. Here’s how:

• Use the right switches and outlets with compatible connectors to prevent metal corrosion.

• Make sure terminal screws are tightly fastened to create a solid connection and ensure smooth electricity flow.

• Apply oxidation inhibitor compound to exposed aluminum connectors in the service panel to protect against oxidation.

Why Aluminum Wiring Can Be Hazardous

Aluminum wiring has some unique challenges:

1. Chemical Reactions:

   • When aluminum meets other metals (like brass), it corrodes, creating heat.

   • Exposed aluminum oxidizes when it touches air, forming a white coating that blocks electrical flow and generates heat.

2. Expansion and Contraction:

   • Aluminum expands and contracts more than copper, which can cause the wires to loosen under terminal screws. This loosening leads to poor connections and overheating at outlets, switches, or terminals.

Aluminum wiring can be safe if handled correctly, but it’s essential to know the risks and have a professional inspect and maintain your home’s electrical system. Staying proactive can help keep your home safe and sound!