Monday, 14 August 2017 06:00

How to Identify Aluminum Wiring

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Residential wiring is generally hidden behind walls and within an outer jacket to protect it, so how do you tell if you have aluminum wiring?

Why is Aluminum Wiring Bad?

Aluminum wiring was used by home building contractors in the mid 1960's to mid 1970's.  It was considered a good option at the time but has since proved to be a major issue.  Over time, aluminum wire connections fail at outlets, switches and panels leading to fire hazard conditions.  Many insurance companies consider aluminum wiring a liability and require remediation before providing coverage.

How to Tell if You Have Aluminum Wiring

 Virtually all residential aluminum wiring was installed as plastic-sheathed or cloth cable (type NM, often called “Romex”) with no readily discernible distinction from a cable with copper conductors. Here are a few ways to tell if a wire is aluminum:

  • Look at the printed or embossed markings on the outer jacket of the electric cables, which are visible in unfinished basements, attics, or garages.
  • If necessary, use a flashlight shining on the surface at a low angle to help make the embossed markings readable.
  • Cable with aluminum conductors will have “Al” or “Aluminum” and other information marked on one side of the cable jacket every few feet along its length. (Note: be sure to read as much of the marking as possible because the marking “CU-clad” or “Copper-clad,” in addition to the “Al” or “Aluminum,” means that the cable uses copper-coated aluminum wire).


If you are unable to identify the type of wire in your home by this method, but you suspect that you have aluminum wire, have a qualified electrician make the determination. If your home has aluminum wiring that has not been remediated, Gentlemen Electric recommends a home electrical inspection to determine what should be done. Visit our Aluminum Wiring page for more details.

Read 5848 times Last modified on Monday, 14 August 2017 22:51
Gentlemen Electric

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