For a home’s ordinary 15- and 20-amp circuits, copper is the standard and the safer choice. Aluminum matters mostly when you own a house that already has it. CPSC says aluminum branch-circuit wiring went into many homes from about 1965 to the mid-1970s. Its connections can overheat, and CPSC recommends a permanent repair by a qualified electrician.
Why older aluminum branch wiring is a concern
CPSC Publication 516 says a copper shortage in the mid-1960s led builders to use aluminum on general-purpose 15- and 20-amp circuits, not just the large dryer and range circuits. Homes built before 1965 are unlikely to have it. A CPSC-sponsored survey found that aluminum-wired homes built before 1972 were 55 times more likely than copper-wired homes to have at least one outlet connection reach “fire hazard conditions.”
The hazard sits at the connections: receptacles, switches, junction boxes and appliance terminals. These connections deteriorate over time, which raises resistance and heat when current flows.
Warning signs
CPSC lists:
- switch or outlet cover plates that are hot to the touch;
- flickering lights;
- circuits that stop working;
- a burning-plastic smell at outlets or switches.
If you notice any of these, stop using the circuit and call an electrician. CPSC advises people without electrical training not to open devices or the panel to look for aluminum. Have a qualified electrician make that call.
Repairs CPSC recognizes, and ones it doesn’t
| Method | CPSC position |
|---|---|
| Complete rewiring with copper | Permanent repair |
| COPALUM crimp connectors (copper pigtails, special tool, authorized installers) | Permanent repair |
| AlumiConn connectors | Permanent alternative where COPALUM is unavailable |
| Pigtailing with ordinary twist-on connectors | Not an acceptable permanent repair; tested connectors overheated |
| CO/ALR-rated switches and receptacles | Better than non-rated devices, but not a substitute for a permanent repair of every connection |
| Common hand-crimped connectors | Do not use with aluminum wire |
A permanent repair has to cover every aluminum connection in the plan, not just the outlet that failed. Ask the electrician to list every circuit and connection point, name the method, and give you a record of the completed locations.
New circuits and larger conductors
Aluminum is still used where the whole system is designed for it, including some service and feeder conductors and large appliance circuits. That is a design decision for an electrician, involving listed terminals, conductor size, torque and local code. It doesn’t make old small-gauge aluminum branch wiring safe.
Questions for an electrician
- Is this older solid aluminum branch wiring, or a different approved application?
- Which circuits and connections are affected, and are there signs of heat now?
- Which CPSC-recognized repair method do you use, and are you trained or authorized for it?
- Will permits or inspections apply, and does the panel need separate work?
Related guides
Sources
This page summarizes CPSC guidance. It does not identify your wiring or authorize electrical work.
Frequently asked questions
Is all aluminum wiring unsafe?
No. CPSC’s warning is about older 15- and 20-amp aluminum branch circuits and their connections. Aluminum is still used for some larger circuits designed for it.
Can I pigtail aluminum to copper with twist-on connectors?
CPSC staff do not consider pigtailing with twist-on connectors an acceptable permanent repair. CPSC recognizes copper rewiring, COPALUM crimp connectors and, where COPALUM is unavailable, AlumiConn connectors.
What warning signs need urgent attention?
CPSC lists hot-to-the-touch switch or outlet plates, flickering lights, circuits that stop working and a burning-plastic smell at outlets or switches. Stop using the circuit and call a qualified electrician.