Aluminum wiring in your house: how to tell, the risks and the repairs
Updated · KeystoneProGuide editorial team
Which homes have aluminum wiring?
Mainly homes built or rewired in the decade from the mid-1960s. The Consumer Product Safety Commission estimated in 2003 that 2 million homes were built with aluminum wire between 1965 and 1973. The Electrical Safety Foundation, a nonprofit safety group, gives a slightly different window, nearly two million homes between 1962 and 1972, and says the switch to aluminum followed a rise in the price of copper in the 1960s.
The concern is the branch circuits: the ordinary 15- and 20-ampere circuits feeding outlets, switches and lights. The foundation notes that aluminum alloy wire is still used today for service entrance conductors and large appliances, and that such installations are acceptable when the connections, breakers and devices are all marked "AL" and installed under the National Electrical Code. Finding aluminum on the main service cable is not, by itself, the problem this guide is about.
Why is it a fire risk?
Because of the connections. The foundation says many receptacles and switches made in that period were not designed for aluminum wire, and that this equipment, combined with poor installation, produced loose connections, which are a potential fire hazard. The CPSC says a failure in these circuits can lead to arcing and a serious fire, and that the fire can spread inside the walls before anyone detects it.
How can you tell if your house has it?
Look, but do not open the panel. The CPSC says that in an unfinished basement, attic or garage the cables may be visible, and aluminum branch wiring will have "Al" or "Aluminum" marked every few feet along the sheathing. It says a home inspector or a qualified electrician can also help identify it. The foundation says the best way to be sure is to hire a licensed, qualified electrician.
The CPSC is firm on one point: consumers should not open the interior of the panelboard or the circuit breaker compartment, because doing so can expose live wires and create an electrocution hazard. Read the cables where they already show.
What are the warning signs?
The CPSC lists four for 15- and 20-ampere aluminum circuits:
- faceplates on outlets or switches that are warm to the touch;
- flickering lights;
- circuits that stop working;
- the smell of burning plastic.
These overlap with the general list the National Fire Protection Association gives for calling an electrician, which also includes warm or discolored outlets and flickering or dimming lights. In an aluminum-wired house, treat any of them as a reason to call soon.
Which repairs does the CPSC accept?
In its 2003 release the CPSC described two routes to a safe result. One is to install new copper circuits, which it said is often impractical for homeowners. The other is a particular crimp-connector repair, which attaches a copper wire to the old aluminum wires and crimps them together with a power tool, making the connection at outlets, switches, lights, circuit breakers and panel terminals. The CPSC said that this method was the only one it recognized as a complete and permanent repair, and that its materials and tools were available only to electricians trained by the manufacturer.
That release is more than twenty years old, and the CPSC's longer booklet on the subject is published as a PDF that was not opened for this guide. Whether newer connector systems have since been accepted is not covered by the pages read. Ask any electrician which method they propose, how they were trained on it, and what the CPSC or the device's listing says about it.
Which repairs does it reject?
The CPSC says that "twist-on" connectors, and receptacles, switches and other devices connected directly to aluminum wire, are an inadequate solution. The foundation's version of the same point is that every connection should be made with wiring devices certified for use with aluminum wire. A quote that replaces outlets and switches one-for-one without addressing the connections should prompt questions.
Does the repair need a permit?
Ask your code office. Pennsylvania's code regulation exempts ordinary repairs from permits, but says adding to or relocating electric wiring is not an ordinary repair. A full rewire with new copper circuits clearly adds wiring; a connector repair at existing devices is less clear, and the regulation does not mention it. The office that issues permits where you live can tell you how it treats the job.
If the house was built before 1978, as every original aluminum-wired house was, the Environmental Protection Agency requires anyone paid to disturb painted surfaces to be certified in lead-safe work practices. Opening walls for new copper circuits may involve exactly that.
What should you ask an electrician?
- How did you confirm the house has aluminum branch wiring?
- Which repair method do you propose, and is it the copper-to-aluminum crimp method the CPSC described, a newer method, or new copper circuits?
- Will you treat every aluminum connection in the house, including lights, breakers and the panel?
- Will the job need a permit and an inspection here?
- If walls will be opened, are you certified for lead-safe work?
The general signs that call for an electrician are in the warning signs guide, more questions for the estimate are in questions to ask before you hire, and the checks on a company are in how to choose an electrician. Electricians are listed on the electricians directory page.
Sources
- May Is National Electrical Safety Month: Good News for Homeowners - Aluminum Wiring Fix Still Available, U.S. Consumer Product Safety Commission
- Understanding Your Home Electrical System, Electrical Safety Foundation International (ESFI)
- Electrical Home Fire Safety, National Fire Protection Association (NFPA)
- 34 Pa. Code § 403.62. Permit requirements and exemptions., Commonwealth of Pennsylvania (Pennsylvania Code)
- Lead Renovation, Repair and Painting Program, U.S. Environmental Protection Agency