Aluminum Wiring

Home Inspection Wiring

Aluminum is a superb metal. It is the most abundant metal on the planet’s crust, it is relatively easy to shape and manipulate, and is by weight a better conductor of electricity than copper. Why then is it that we get so concerned when we see aluminum wiring in a home inspection?

How do I know if I have Aluminum Wire in my Home?

In the late 60’s to late 70’s, copper, which was the preferred metal for house wiring, went through a sharp price increase. Home builders and wire suppliers looked to aluminum, which was also a good conductor of electricity, to replace copper wiring in houses. As inventory of copper wiring varied from market to market (and even down to what was on the spools in the back of the electricians vans), there is no particular start and stop date to when you will find aluminum wire in homes. The only way to know for sure is to observe the wire you have. As working with electricity is a major life safety hazard, only have a professional Home Inspector or Electrician look into this for you.

My Home Inspection Report says I have Aluminum Wire. Isn’t all Aluminum Wire Unsafe?

Stranded Copper and Aluminum Wire Examples

Stranded Copper and Aluminum Wire Home Inspection

We see ‘good’ aluminum wire in nearly every home inspection we do no matter the age of the house or condo. Power companies typically use aluminum wire to bring electricity from the street into the electric panel in our home. Also, even in new construction, aluminum wire often feeds stoves, dryers, and other high amperage devices in our homes. This type ‘good’ type of aluminum wire is ‘stranded’ aluminum wire meaning that there are multiple strands wound together into the wire bundle which conducts electricity. Stranded aluminum has not had the same issues as its problem cousin, the solid-core aluminum wire. On our Home Inspection Reports, we always clarify if it is stranded aluminum (which is not a concern in a home inspection) or solid core aluminum wire, which is a concern.

What is wrong with Solid Core Aluminum wire?

No wire is a perfect conductor of electricity. When electricity runs through a wire, some of the wires natural resistance to electricity causes a power loss in the form of heat. When wire is heated, it expands slightly and this is at the root problem of aluminum wire in homes. Aluminum expands then shrinks more than copper when electricity is turned off and on. Over time, this expansion and contraction can cause the wires to creep out of the connections at light fixtures, power outlets, and other switches. When the wires eventually creep out of the connections, electricity may then arc the gap between the wire and the connection. Arcing electricity is essentially lightening and is extremely hot, hot enough to start fires in the wood, paper backed drywall, plastics, and other materials we build our homes from. This is why insurance companies have issues with insuring aluminum wiring.

Solid Core Aluminum Wires

Solid Core Aluminum Wires

Shortly after a higher rate of electrical fires from Aluminum wires was observed by electrical authorities, new standards for outlets and switches were developed (and even re-developed) to make aluminum wire compatible. These measures were effective. However, early aluminum wire homes did not use these compatible devices, and over time future occupants have replaced many of these devices with more current designs and colours. In a home inspection, we now have to presume that the connections are likely not correct and advise our clients to consult an electrician about possible remediation measures.

How do I Fix a Home with Solid Core Aluminum Wire?

There is a lot of debate in the building remediation community about the best way to manage the solid core aluminum wire creep issue. The three most common solutions are:

  • Re-Wire the Home - This is the ‘best’ solution as it completely replaces the aluminum wire with copper wire. However, it is the most expensive and disruptive solution as it requires creating holes through the whole house to pull new wires from the electric panel to all outlets, switches, and lights.
  • Pig-Tail Connections - There is a manufacturer of purple wire nuts that can allow pig-tailing the aluminum wire to a short length of copper wire which then connects to the outlet, switch, or light. When manufacturer directions are followed, this can be an effective solution. However, many installations do not follow the manufacturer’s guidance.
  • Install Aluminum Compatible Devices - There are outlets, switches, and lights rated for use with solid core aluminum wire and use of these should eliminate risks. However, there is some more recent discussion that the aluminum used in the 60’s and 70’s is a different alloy than what is made today and that unless the installer puts in devices compatible for the correct alloy, risks may remain.

Should I buy a Home Now that I know it has Solid Core Aluminum wire?

This is the most common question people want the answer to from us when we find aluminum wire in a home inspection. I have two schools of thought on this question. First, if this is your dream home and everything else about the home is perfect for you, then you should consider the cost of re-wiring in the purchase price. 

  • In a recent house we inspected and followed up on, we learned that the re-wiring cost in a 2,000 sq ft home was about $5,000. The home was purchased for about $600k. The re-wire work was worth less than 1% of the purchase price of the home and as the house was a dream house to the buyer, it was well worth the 1% to the buyer to do.

My other school of thought is that there are no perfect homes in a home inspection and buyers always have to assume some risk in their home purchase. If the home is great other than the aluminum wire, with some help from an electrician you can mitigate the aluminum wire risks to an acceptable level and still buy your dream home.

By James Bell - Owner/Operator of Solid State Inspections Inc.

Disclaimer: Solid Core Aluminum wire carries risks that require professional attention. If you learn you have solid core aluminum wire in a home inspection or at any other time, always consult an electrician to help you understand your options for electrical safety.