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Addressing Aluminum Wiring: Should You Be Concerned?

William Steyskal

By William Steyskal

Why do home inspectors call out evidence of aluminum wiring? Why should I be concerned? How concerned should I be? I get these questions from your clients all the time. To answer these common inquiries, let me begin by posing a question. If aluminum wiring is so bad, why is it used in the first place?

The History of Aluminum Wiring
Well, to answer that we need to look back in time. Copper is the proper metal. Aluminum is not terrible, though. In fact, aluminum was widely used in older homes built in the World War II era until the 1950s. It made a resurgence in the 1970s and again as recently as the 1990s.

The use of aluminum wiring was largely due to cost concerns. Copper is far more expensive, making aluminum a soluble and affordable substitute. Plus, during WWII, copper was needed for other manufactured goods – i.e., ammo – and became a scare commodity to homebuilders. They turned to aluminum.

Since that time, aluminum wiring has been installed either because of cost or supply.

Why Should Your Client Be Concerned?
Let’s turn back to the issue at hand – why is aluminum wiring called out and why should its presence concern your client?

Aluminum is soft. It will expand under heat and retract when not in use. This expanding and retracting is the main reason a good home inspector will point out its presence as it tends to affect the connections, especially at wall receptacles. The constant expanding and retracting will loosen the connection and cause unstable power supply and shorts that can led to burning and even fires.

Aluminum is less ductile. When subjected to bending, the aluminum is more likely to break down internally. This will lead to resistance of the electrical current, which will cause a buildup of heat – exacerbating the expanding and retracting issue.

Aluminum is more prone to oxidation. As the wiring is exposed to oxygen over time, it will become oxidized. In addition, oxidized copper is still more conducive than aluminum oxide. If oxidized, aluminum can deteriorate and present a fire hazard.

Aluminum vibrates excessively. As the electrical current courses through aluminum wiring, it causes extreme vibration. Over time, the vibration can cause connections to loosen. The vibration affects aluminum wiring more than copper wiring.

The Level of Concern
Most home inspectors will advise that a licensed electrician be called to – at the very least – determine the viability of the wiring at the receptacles. If your client is looking to purchase the house, advise them to ask the sellers if any electrical work has been done and if so where. Areas of the electrical infrastructure that haven’t been maintained for some time will be the areas of most concern. These are areas where the connections could have been compromised.

There are some rather simple fixes that an electrician can apply to minimize the risk of aluminum wiring without having to rewire the entire home in copper. For this type of project, I strongly recommend that professional electricians be employed. This is not the project they want to DIY.

William Steyskal is the general manager for HouseMaster Home and Termite Inspections in Phoenix, Prescott and Flagstaff. He is also the regional director of sales and technical training. For more information, call (480) 345-8570 or visit