Why Is Aluminum Wiring An Issue In Homes?

Date Published: April 6, 2021

If you own a home built in the late ’60s to early ’70s or are planning on purchasing a home in this age range, it is quite possible that the home was built with aluminum wiring.

According to the US Consumer Product Safety Commission, homes with aluminum wiring are 55 times more likely to have electrical wire connections reach dangerous “fire hazard conditions” than homes wired with copper wiring.

So, this begs the question: Why do homes built during this time period have aluminum wiring? And more importantly, why is aluminum wiring an issue in homes?

Why do homes have aluminum wiring installed?

In the late ’60s and early ’70s, the United States was in the middle of the Vietnam War and we had a shortage of copper. This forced the price of copper up as the military demand was high and our mostly imported supply at this time was low.

Because of the shortage, another metal was chosen with which to wire homes, and aluminum seemed to be a good choice.

Aluminum wiring was less expensive and easy to come by. It is also easier to work with than copper which made it seem like a good alternative.

What Changed? Why is Aluminum wiring a problem in homes?

Different metals will react differently when an electric charge, or current, is passed through them. Aluminum expands and contracts more readily than copper does.

Also, aluminum is more brittle than copper, so, it is not as flexible and will break easier if twisted or stretched. Because aluminum expands much more when heated than copper does, excess heat expansion can force the wire out from under terminal screws, loosening its connection to the attached device, outlet, switches, circuit breakers, and junction boxes.

Aluminum wiring at the neutrals

This exposed wiring can develop oxidation and corrosion when the metal is exposed to the air. If the aluminum wire connections become loose, this can disrupt the electrical flow to these connection points.

If more electrical resistance exists inside the wire, it will generate unwanted heat on the wiring. That additional heat will cause the wire to expand, and the more the wire expands, the looser the wiring connections can become overtime at the connection points throughout the home.

Just because there isn’t a problem in the home now, doesn’t mean there may not be a problem in the future. This is a problem that can slowly get worse over time as the wires get progressively looser at their end connection points.

How do I fix aluminum electrical wiring?

Completely rewiring a home isn’t really a practical solution, as it would require tearing into walls and ceilings, and it is extremely expensive. Fortunately, this is typically not necessary.  The primary repair method is to address the end point connections to re-secure them.

The most common repair for this is called pig tailing, and it is a relatively simple repair. However, it can be time-consuming with high labor charges.

At each connection point throughout the home, the aluminum wire is disconnected from ALL of the devices (the circuit breakers, outlets, wall switches, and junction boxes).

The end of the aluminum wiring is then connected to a small piece of copper wire by using an encapsulated wire-nut filled with an antioxidant compound.

The new piece of copper wire is connected to the existing connect point (the circuit breakers, outlets, wall switches, and junction boxes) creating a safe connection with the device.

pigtailing aluminum wiring

There are several companies that manufacture specific wire nuts (usually purple in color). This makes them fairly easy to find during a home inspection or rental inspection.

Depending on how much aluminum wiring and how many connection points there are in the home, this can range from a couple of dozen to several hundred splices. While the wire nut device is inexpensive, the cost to repair can add up as the electrician’s time increases.

However, the cost is negligible as this is a potentially hazardous and, in some cases, life-threatening issue.

Whether it turns out to be a smaller job or a bigger job, it is, of course, a good idea to get several estimates from qualified, licensed, electricians who are familiar with the pig tailing process, so that you can make an informed decision going forward.

Why Is Aluminum Wiring An Issue

How we find aluminum during a home inspection.

When we perform a home inspection, the electrical panel cover is removed. Typically, aluminum wiring will be visible in the panel, and you can view the wire material at the breakers and the neutral bar.

Since the wiring was installed during a specific time frame, we are more proactive in looking for the wiring in specific age homes.

If proper repairs were made, you will see special breakers or pigtails within the panel itself.

When we do encounter aluminum wiring, we typically will remove a few sample outlet covers to verify that pig tailing has been installed behind the outlets as well.

While a standard home inspection does not allow the time to view every outlet and connection in a home, it gives you, as the buyer, the information needed to request further information from the seller.

We recommend asking about repairs and finding out if they were done professionally and having an electrician review the repairs as needed.

Aluminum Wiring Today.

While problems were found with aluminum wiring on 15 and 20 amp circuits, proper use cases were also found. Aluminum wiring is still installed today in certain applications.

For example, stranded aluminum wiring was found to be safe, and it is used on larger power connections such as 220v breakers, AFCI and GFCI jumper cables, and even your large main electrical overhead lines!

We are constantly learning how to safely use building materials, and aluminum will find its place in the electrical world over time.

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About the Author: Todd Brualdi

Todd is a Certified Home Inspector and an NRPP Certified Radon Professional and has been in the industry for nearly ten years. He has experience in “Fixing and Flipping” turn-of-the-century bungalows in the Downtown Denver area, and had his own business as a residential handyman. Todd brings a broad experience base to our inspection team.

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