What Is the Difference Between Aluminum and Copper Wiring?

July 19, 2018

You may have heard home builders or designers mention that aluminum and copper wiring should never mix in a home. You may have also heard some say that aluminum wiring is better, while others swear by copper wiring. But unless you have professional electrical training, you may not have ever learned the difference.

At Buzz Electrical, we are familiar with both aluminum and copper wiring in residential homes. To help you better understand why these two metals shouldn’t mix and which one is better suited for electrical wiring in your home, our team has created this written guide to these household wiring materials.

History of Aluminum and Copper Wiring

Historically, copper wiring was used for electrical systems inside homes and other buildings, while aluminum was used for larger projects like power grids and overhead transmission lines. From the 1960s to the mid-1970s, the price of copper fluctuated upward and aluminum became a more cost effective option. During this era, aluminum wiring temporarily replaced copper for home interiors. However, over time problems with older, traditional aluminum wiring and the way it differed from copper became apparent. Today, copper wiring or newly developed aluminum designed to adhere to current electrical codes are used inside residential construction projects. Because of the safety risks associated with old-school aluminum, most electricians recommend rewiring homes built in the 60s and 70s with this outdated wiring.

Key Properties of Aluminum Wiring

Aluminum is a softer metal, which can make it easier to work worth and ideal for smaller electronic devices. However, this makes it more susceptible to damage within a home. When electrical current passes through aluminum, it heats up and expands much more than copper does. For some homes, this can greatly increase the risk of an electrical fire. While both copper and aluminum can rust over time, once aluminum rusts it can no longer properly conduct electricity. This can restrict your electrical system’s efficiency and pose further risks for fire. One of the most positive aspects of aluminum wiring is the price. Aluminum is approximately half the cost of copper, making it a more budget-friendly solution.

Key Properties of Copper Wiring

Copper has been the international standard for residential wiring for over a century. It is durable, yet still flexible and it is highly conductive. If copper rusts over time, the oxidized metal can still conduct electricity normally. It is widely considered to be the better choice for any residential electrical wiring because it is safer and holds up better over time.

Aluminum and Copper Wiring in Your Home

When constructing a new home or purchasing an existing home, we recommend making sure you have copper wiring for your electrical system. If you live in a home that already has aluminum wiring, make sure that you remain consistent when adding any additional wiring. Because these two metals are so different, it will be detrimental to both if they are combined in the same electrical system. A chemical reaction between them can lead to oxidization and rust, which affects the performance of the aluminum components. Since they heat up and expand or cool down and contract at completely different rates, this can loosen their connectors and pose risks of electrical arcs or fires. If you think your home might have both aluminum and copper wiring installed by an amateur, call an electrician for rewiring right away. If you have all aluminum wiring across your home electrical system, you can also upgrade to copper across the board with help from a licensed, professional electrician.

We hope this beginners guide to aluminum and copper wiring will help keep our customers safe and informed about the wiring in their walls.

Family-owned and operated Buzz Electrical is Fayetteville’s leading electrical company! If you need to have the wiring throughout your home electrical system inspected or replaced, we are here to help. Give us a call at (479) 267-2899.