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Working With Aluminum Wiring


Installing electrical systems with aluminum wiring was a common practice for homes in the late 60s and 70s. At the time, it was considered a cheaper alternative to copper wiring. Being the more economical option, aluminum wiring became the norm for almost a decade, not only in Alberta but all-over North America. Unfortunately, this cheaper substitute was revealed to create some serious safety issues.

Why it is Dangerous

It turns out that aluminum differs greatly from copper wiring in a few important aspects in addition to being less conductive.

  • Hardness. According to the Brinell Hardness Scale, copper is more than twice as hard as aluminum. This makes it very easy to damage the soft aluminum wires and inadvertently create hot spots.
  • Thermal Expansion. No matter the type of wire, the electrical flow will cause it to heat up and ultimately expand. When it cools, the wire contracts. Copper’s thermal expansion is much less than that of aluminum. The relatively extreme and constant size changes cause aluminum wires to loosen out from under the terminal screws that hold them in place. This results in loose connections, overheating, and even electrical fires.
  • Rust Characteristics. Rust is the formation of an oxide on the surface of a metal. Copper oxide is conductive and will not impede the electrical current. Aluminum oxide is not a good conductor and will interfere with the flow. Not only is this inconvenient, but this interference can cause overheating.

How You Can Tell

Despite the risks, many homes today still contain outdated electrical wiring simply because they’ve never been updated. If you own an older home, it’s a good idea to know what you’re dealing with and determine whether or not the electrical wiring is aluminum or copper. The simplest way to do this is to check your electrical panel, unfinished basement, or attic to see if the cables are marked AL, ALUM, or ALUMINUM. Another way is to view exposed wires from an outlet or switch. In most cases, all you need to do is unscrew the cover. Never go beyond that without a professional electrician present. Aluminum wire will be silver and copper wire will be a distinct reddish-brown colour.

What You Can Do

If your home is outfitted with aluminum wiring, contact a licensed electrician for an inspection right away. At this point, you will have two options: to completely rewire the house or to make upgrades that will greatly reduce the chances of disconnection and fire. Your contractor will be able to work with you to determine which option is best for your situation.

Working with a licensed electrical contractor is the only way to ensure that you and your family are protected properly. Our team can service your home in the Calgary area. Contact us today for a quotation.

Written by 4-Star Electric

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