Your home might have aluminum wiring and you need to know what to do if it's there
Aluminum Wiring Can Be Hazardous, Here’s What to do About It
Updated on Jan. 27, 2025
If you have aluminum wiring in your house, you might have a fire waiting to happen. Many houses built or renovated between 1965 and 1972 were wired with aluminum instead of copper, and those are 55 times more likely to have “fire hazard conditions,” according to the U.S. Consumer Product Safety Commission.
“During this time, there was a push to use aluminum because of the rising cost of copper,” says Daniel Vasilevski, director of Bright Force Electrical.
The wiring itself isn’t the problem, because aluminum does conduct electricity safely. The trouble comes at the connections. Since aluminum wiring expands and contracts more dramatically than copper, over time that loosens the connections and creates gaps.
“These gaps create high resistance and increase the risk of sparkling, which is exactly what’s needed for a fire to start,” says WG Hickman, owner at Tri-County Air Service.
Connections where aluminum wiring meets outlets, switches or other wires, are the weakest points. Another problem with aluminum is that it oxidizes more easily.
“It’s important to note that older homes with aluminum wiring are not necessarily safe just because they have not yet caught fire,” says Daniel Mock, vice president of operations at Mister Sparky. They are in fact at greater risk due to the buildup of oxidation on the wires over time.
Fix the problem
Completely rewiring your home isn’t practical in most situations, as that would mean tearing into walls and ceilings. Also, unless you have extensive experience working with electrical components, it’s best not to risk a DIY aluminum wiring fix.
But a licensed electrician can make the connections safe by adding a short section of copper wire to the end of each aluminum wire. That way, copper rather than aluminum will be connected to each switch, outlet or other device.
To do this, electricians use special connectors designed for aluminum-to-copper transitions, such as AL-CU rated wire nuts or other approved devices. COPALUM connectors are preferred by the CPSC, but they require a trained contractor and a special tool. AlumiConn is another brand that can be purchased from online suppliers. These connectors can be installed by any trained electrician but may require that existing junction boxes be replaced with larger ones to make room for the connectors.
Electricians will also put a small amount of anti-oxidant compound (like Noalox or Penetrox) to the exposed aluminum wire before securing it to the connector, which will prevent oxidation and reduce the risk of resistance buildup (which results in overheating), says Vasilevski. It’s also necessary to replace incompatible outlets and switches with devices specifically labeled as CO/ALR (Copper/Aluminum Rated).
“These outlets and switches are designed to handle the unique properties of aluminum wiring, including its tendency to expand and contract,” says Vasilevski. “Using standard fixtures that aren’t rated for aluminum wiring increases the risk of loose connections, overheating and arcing.”
Vasilevski also warns not to mix aluminum and copper without proper connectors. “If you need to connect aluminum and copper wires, never twist them together directly,” he says. This is because aluminum and copper expand and conduct electricity at different rates, so if you do that, it will result in galvanic corrosion, which weakens the connection and increases resistance.
Limit the Scope of DIY Repairs
If you have basic knowledge, you can replace all outlets and switches in your house labeled “CU-only” with the ones rated CO/ALR, says Hickman. Those are compatible with both copper and aluminum and rule out the possibility of loosened connections, arcing and overheating of the wiring,
But “Things like installing COPALUM or AlumiConn connectors and a complete home rewiring shouldn’t be done on your own, no matter how confident you feel, and should always be handled by a licensed electrician,” says Hickman. “There is no compromise”.
If calling an electrician is not possible, aluminum fixtures, plugs and switches need to be crimped onto their connection points, says Todd Tripp, a home improvement expert with JustAnswer to prevent them from loosening with usage and the contraction and expansion of heat. “They just need to be secured extra tight and not allowed to become loose,” he says.
About the Experts
- Daniel Mock is vice president of operations at Mister Sparky, and he has more than 15 years of experience in home services and the electrical sector.
- WG Hickman is owner at Tri-County Air Service in Mississippi, which has been providing electrical and HVAC services for almost 20 years.
- Daniel Vasilevski is director and owner of Bright Force Electrical and has worked as an electrician for more than a decade.
- Todd Tripp is a general contractor and founder of Trip Mills Builders in upstate South Carolina, and a home improvement expert with JustAnswer.
