Solid Aluminum Wiring

This week’s inspection highlight was a home built in the 1970’s, which had single strand or solid aluminum wiring.

In the mid-1960’s the price of copper increased, so the housing industry looked towards a more cost-effective replacement for electrical wiring in homes. Aluminum was chosen. Single Strand Aluminum was commonly used until the mid-1970’s when the deficiencies of aluminum versus copper were realized.

These deficiencies include:

• Aluminum expands and contracts with changes in temperature more so than copper. Over time this can cause connections to breakers, outlets, and switches to loosen. This could cause fire or shock hazards.
• Aluminum is more susceptible to weakening and breaking when bent or otherwise abused compared to copper.
• The surface of aluminum deteriorates (oxidizes) when exposed to oxygen. The resulting compound created by the oxidization is aluminum oxide, which is not very conductive. Over time the oxidization weakens connections and creates a fire hazard.
• Aluminum is more malleable than copper. When compressed, Aluminum can continue to change shape, which can lead to loose connections.
• There are more conditions, but I think you get the idea.

Is single strand aluminum wiring unsafe? Not necessarily. However, whenever a home inspector sees single strand aluminum wiring, a home inspector should call it out for further investigation by a licensed electrician. The electrician may ultimately say it is okay, but there are considerations or modifications the electrician may use to come to this decision. Some of these include:

• The electrical panel should be compatible with aluminum wiring.
• The breakers should be compatible with aluminum wiring.
• The outlets and switches should be compatible with aluminum wiring.
• The electrician may recommend:
  • Adding anti-oxidant paste to the aluminum wiring.
  • Rewiring the house with copper wiring (expensive, but the best solution).
  • Adding COPALUM crimps, which is a special connector that adapts the aluminum wire to a copper wire that is then attached to the breaker, outlet, or switch. (still expensive, but less so than rewiring the house).
  • There are more possible modifications, but these are considered the best.

A final point to remember regarding solid single strand aluminum wiring is that some insurance companies may not cover you in the event of a fire due to aluminum wiring. Be sure to check with your insurance company to may sure you are covered.

To schedule a home inspection in Tucson, Marana, Oro Valley, Vail, and other parts of the Tucson metro area, contact Tanque Verde Home Inspections at 520-462-8844.