By Pat Hill, Manager of Quality Assurance, Alexander & Schmidt

In a New York Times article a number of years ago, “The Fire Dangers of Aluminum Wiring,” the Consumer Product Safety Commission was cited estimating that “two million homes in the United States were built or renovated using electrical circuits with aluminum wiring. And, according to the commission and specialists in the field, unless certain safety procedures are undertaken, every outlet, light switch and junction box connected to such circuits is a fire waiting to happen.”

Residential properties that were built, re-wired or had circuits added between 1965 and 1973 could have aluminum wiring (rated 20 A or less and #8, #10, or #12 gauge wire) often referred to as “old technology.” CPSC research shows that these homes are more likely to have one or more connections reach “Fire Hazard Conditions” than are homes wired with copper.

”Post 1972″ aluminum wire introduced aluminum wire “alloys” however; this did not solve most of the connection failure problems. Homes built prior to 1965 or after 1973 will likely have copper wire.

Methods of Repair

The CPSC recognizes two methods for remediation of aluminum wiring in branch circuits.

  1. Replacement of the aluminum wiring and,
  2. The COPALM crimping method.

The first choice is the best choice, however this will often be an impractical choice in condominiums and townhouses. The second choice involves attaching a piece of copper wire to the existing aluminum wire with a specially designed metal sleeve and powered crimping tool.

Since the above, CPSC-approved methods, are generally cost prohibitive to homeowners and associations, many electricians recommend other less costly methods including “Pig Tailing” and the use of CO/ALR devices.

“Pig Tailing” involves attaching a short piece of copper wire to the aluminum wire with a twist-on connector. These connections are prone to overheating.

The other repair recommended by the industry uses switches and outlets labeled “CO/ALR.” Though Underwriters Laboratories (UL) lists these devices especially for use with aluminum wire, CO/ALR connectors are not available for all parts of the wiring system (for example, for permanently wired appliances and ceiling mounted light fixtures). At best, these devices are an incomplete repair. Further, CO/ALR wiring devices have failed in laboratory tests when connected to aluminum wire typical of that installed in existing homes.

How to Recognize Aluminum Wiring

  1. Was the building constructed between 1965 and 1973? If so, there is a good chance there is aluminum wiring. If the building is older than 1965 but had circuits added or was re-wired between 1965 and 1973 there is also a good chance that there is aluminum wiring.
  2. aluminium wiringLook at the wire “gauge” or size: Aluminum wire must be one wire gauge size larger for a given circuit than if copper wire were used, you will rarely see #14 Gauge aluminum wiring. A 15-Amp circuit could be wired with #14-Gauge copper wire but, if aluminum wire were used it would have to be #12- gauge.
  3. aluminium wiringLook at the Jacket on Exposed Wiring: Most wiring has printing or embossed lettering on the plastic wire jacket. Find an area where there is exposed wiring such as the attic or entering the electric panel and look at the plastic jacket. Some aluminum wire has the “ALUMINUM” or “AL” plainly marked on the jacket. You may also see a specific brand name like “KAISER ALUMINUM.”
  4. aluminium wiringRemove an Outlet Cover or Switch Plate: These covers are easily removed with a small screwdriver. Look for silver-colored wire at the stripped wire ends under the terminal screws.
  5. witing04Look for Signs of Repair Methods: Look inside of the box for signs of COPALUM crimps, “Al/Cu” or “CO/ALR” devices wiring05or “Purple twist” connectors.

Patrick Hill, Manager of Quality Assurance, Alexander & Schmidt

profile-hillPatrick Hill runs Alexander & Schmidt’s quality assurance operations, overseeing all technical functions. He has over 25 years of experience in the occupational safety and health field, the last 12 years of which have been spent at A&S. (See Pat’s bio) Pat is the author of a highly acclaimed textbook entitled Defining Risk Assessment.