Dangers of Aluminum Wire

Dangers of Aluminum Wire

Aluminum makes good cans but not the best wire.

Copper prices increased dramatically from the mid 1960s to the mid 1970s. Pennies were no longer made out of pure copper but rather became zinc with copper plating. Builders switched from copper wiring to aluminum wiring for homes. According to The New York Times, about two million homes were wired with aluminum. Serious problems became apparent, leading to a Consumer Product Safety Commission (CPSC) investigation. If your home has aluminum wiring, its best to inform yourself of the facts.


The New York Times reported the problem is not with the wiring but with the end connections. Oxidation is a significant problem with aluminum. Oxidation is to aluminum what rust is to iron. A white powdery substance, called aluminum oxide, forms on the surface of the aluminum. Oxidation forms because of moisture. When the wires oxidize at the wall switch or outlets, it stops conducting electricity. Therefore, the area of the connection becomes a resistor. The side-effect of resistance is heat. Licensed home inspector Daniel Friedman, quoted by The New York Times, stated that enough heat can be created by the oxidation problem to start a fire. The CPSC stated in 1974 that they received reports of many home fires traced to overheated aluminum terminal wiring.

Thermal Expansion

 All metals expand when heated and contract when cooled. Aluminum expands and contracts at a far greater rate than copper. Wires usually run in attics, and in exterior walls. In the summer, an attic may exceed 100 degrees Fahrenheit. In the winter, an attic may drop to 30 degrees or less. This constant seasonal expansion and contraction affects the terminal screws at the wall switches and outlets. The end result is the terminal screws loosen up, leading to a poor connection. A poor connection leads to heat. The heat may be hot enough to start a fire.


 A seasoned electrician knows never to nick a wire when stripping it to make terminal connections. A nick creates a stress point, leading to eventual wire breakage. Qualified electricians use specialist tools to strip the wire, so only the insulation is cut. An unqualified person does not understand this and perhaps just uses a pocket knife to strip the insulation. Aluminum is a very soft and weak metal. Over time it will break at the nick point due to stresses. The breakage leads to a short and sparking, since the wire is now "flopping around" inside the junction box. Sparking leads to a fire. If your house has aluminum wire, you cannot trust that the installer did a proper job with no nicks. The CPSC specifically states that only a qualified electrician should have installed aluminum wire, since a nick-free installation is critical.

Overall Fire Danger

The possibility of fire is great with aluminum wiring. To avert this, we have several recommendations.   the best cure is to replace the aluminum wiring with copper. The second best cure is to use special connectors at the junction boxes. These connectors transition from aluminum to short lengths of copper wire for the terminals. We at Briggs elec recommends a thorough inspection by qualified personnel and to replace switches and outlets. The new switches and outlets should specifically state they are designed for copper and aluminum wiring.

Briggs electrical service provides residential, commercial and industrial electrical services.

Located in Matthews North Carolina between hwy 74 hwy and 485 to easily provide Electrical Service in Matthews North Carolina and Electrical Service Charlotte North Carolina and Electrical Service Union County, Weddington, Wesley Chapel, Waxhaw North Carolina

  Briggs Electrical Service & Lighting Design.

500 East Matthews Street Matthews, NC 28105

Phone number (704) 847-5737  

Fax number (704) 972-0532.

The owner Peter James Briggs

Email james@besld.net

Office manager Trinity Reynolds 


Main website http://www.besld.net  80 pages        2nd website http://www.besld.com  19 pages


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