wiring of a house
Laura Scudder, Knob and tube 1930, CC BY-SA 3.0

In the mid-1900s, most homes were built with aluminum wiring because they were a lot cheaper compared to copper. Most of those houses never got remodeled. Hence, thousands of old homes are said to have aluminum wiring or another potentially dangerous type of wiring, knob and tube.

However, just because a house is old doesn’t mean it has aluminum wiring. That’s why an inspection is important. Most homeowners looking to sell their property may not make it clear so you’d have to investigate it yourself. Often, having aluminum wiring isn’t so bad but when the wrong receptacle or conductors are installed, it could cause some serious damage.

Aluminum wiring tends to overheat rather easily and is a far softer metal than copper. You may have aluminum wiring if you have flickering lights, tripped circuits, burned insulation, and heated outlets. To avoid all this, here are some ways you can know you have aluminum wiring.

  • Through Exposed Wiring: Exposed wiring is the most common way to know you have aluminum wiring. If your wires are exposed, check if they have a shiny steel-like exterior. If they do, you have aluminum wiring. Also, if they have a more reddish-brown color, then you have copper wiring.
  • Heated Outlets: Overheating is a common sign of aluminum wiring. Having outlets that are a little warm is quite normal. However, when your outlets feel too hot to touch, you need to have your house inspected. Bear in mind that heated wires often burn, so watch out for strange odors as well. Your first line of action would be to turn off the breakers to stop the power flow and then call a professional for help.
  • Flickering Lights and Bad Fixtures: While in some situations it’s normal for your lights to flicker, it only lasts for a second. If your lights flicker whenever you plug in any appliances or you have to change out your light bulbs frequently because they burn out so fast, it may be because of poor electrical connectors caused by the aluminum wiring.
  • Buzzing, Arching, and Shocks: Buzzing sounds from an outlet or a switch are a sign of excessive heat. Does your outlet constantly spark when you plug an appliance? Chances are you have aluminum wiring.
  • Labeled Casing: Another way you can figure out you have aluminum wiring is to check the wires themselves. Aluminum wiring manufactured before 1977 would be marked with the word ALUMINUM or ALUM or AL after at least every 12 inches. If it was manufactured after May 1977, the labeling would be ALUMINUM ACM, ALUM ACM or AL ACM.
  • Call in a professional: Before you buy a house, you should call in a professional electrician to check the electrical condition of the home. If it needs to be remodeled and rewired, it would be far easier to discuss that and consider if a full repair is something you’d be interested in. If your home has any electrical problems, then you need professional help.
How To Identify Aluminum Wiring was last modified: August 30th, 2022 by Brian Hortin