If your business or home currently has aluminum wiring, you may want to start considering your options for replacement. Aluminum wiring can pose a significant threat of danger to your life; contact 4-Star Electric for an electrical inspection to start the process of replacing or repairing dangerous aluminum wiring.
Does My Home Have Aluminum Wiring?
Many homes that were built in the 1960s–1970s will typically have aluminum wiring within their walls. Aluminum is a material with a low cost of production, and because it was thought to be a successful way to transmit and distribute electricity, electrical contractors used aluminum wiring instead of copper during this period of time. Houses that contain aluminum wiring are more prone to damage due to electrical fires and hazards.
Aluminum wiring is lighter than copper wire thus, preventing cables from sagging. Aluminum wiring, however, quickly proved to be a hazard in both residential homes and commercial buildings.
Some signs that show if your home currently has aluminum wiring are:
- Aluminum wires have a specific color and can make them discernable from other metals.
- Wiring-device binding terminals for use with aluminum wire have been marked CO/ALR, which stands for “copper/aluminum revised.”
- Plastic wire jackets will have the word “aluminum” or the initials “AL” on them.
- Your home was built or expanded between 1965 and 1976.
What are the Dangers of Aluminum Wiring?
Aluminum wiring can separate from the screws on electrical outlets, switches, or lights, which can create a poor connection and cause the wire to heat up. The heat can cause the aluminum to oxidize, which creates an even worse connection and more heat and can eventually start a fire.

Qualities of Aluminum as a Metal
These qualities of aluminum make it a poor material for wiring when compared to other, safer metals like copper:
- Higher electrical resistance. Aluminum has a high resistance to electrical current flow, which means that given the same amperage, aluminum conductors will have to be a larger diameter than would be required by copper conductors.
- Less ductile. Aluminum will fatigue and break down more readily when subjected to bending and other forms of abuse than copper, which is more ductile. Fatigue will cause the wire to break down and will increase its resistance to electrical current, leading to a buildup of excessive heat.
- Galvanic corrosion. In the presence of moisture, aluminum will undergo galvanic corrosion when it comes into contact with certain dissimilar metals.
- Oxidation. Exposure to oxygen in the air causes deterioration to the outer surface of the wire. Aluminum wire is more easily oxidized than copper wire, and the compound formed by this process – aluminum oxide – is less conductive than copper oxide.
- Greater malleability. Aluminum is soft and malleable, meaning it is highly sensitive to compression. If a screw has been over-tightened on aluminum wiring, the wire will continue to deform or “flow” even after the tightening has ceased. This deformation or “flow” will create a loose connection and increase electrical resistance in that location.
- Greater thermal expansion and contraction. Even more than copper, aluminum expands and contracts with changes in temperature. This process will cause the connections between the wire and the device to degrade.
- Excessive vibration. Electrical current vibrates as it passes through wiring. This excessive vibration can cause connections to loosen.
Can You Connect Copper Wire to Aluminum Wire?
Incorrect repairs to aluminum wiring, such as connecting aluminum wire to copper wire with copper twist-on wire connectors, can make the problem even worse and can be dangerous. The proper way to repair aluminum wiring is to have a licensed electrical contractor connect these wires to short pieces of copper wire with crimped or screw-on connectors specifically designed for this use.
Aluminum to Copper Connectors
The preferred method that our electricians take to repair and connect aluminum to copper connectors is:
- Pigtailing. This method involves attaching a short piece of copper wire to the aluminum wire with a twist-on connector where a deox agent must be used with the connection. The copper wire is connected to the switch, wall outlet, or another termination device. This method is only effective if the connections between the aluminum wires and the copper pigtails are extremely reliable. Keep in mind that pigtailing with some types of connectors can lead to increasing the hazards presented by aluminum wiring in the first place.
There are other methods that can be used to connect aluminum to copper connectors if your electrician may prefer:
- CO/ALR connections. These devices cannot be used for all parts of the wiring system, such as ceiling-mounted light fixtures, or permanently wired appliances, and as such, CO/ALR connections cannot constitute a complete repair.
- A crimp connector repair consists of attaching a piece of copper wire to the existing aluminum wire branch circuit with a specially designed metal sleeve and powered crimping tool. This special connector can be installed only with the matching AMP tool. An insulating sleeve is placed around the crimp connector to complete the repair
Contact An Electrician For Help
Always contact your electrician for help concerning aluminum wiring and to understand the dangers of improper wiring.