Aluminum Wiring: What It Means on Your Home Inspection Report

When a report says "aluminum branch circuit wiring" or "solid conductor aluminum," the inspector saw single-strand aluminum wire, instead of copper, on the ordinary 15- and 20-amp circuits that feed outlets, switches, and lights. The CPSC explains that a copper shortage in the mid-1960s led builders to use aluminum for these everyday circuits. Homes built before 1965 are unlikely to have it; cable installed between 1965 and the mid-1970s, in new homes, additions, and rewired circuits, may contain it.

You can often confirm it yourself without touching anything. In an unfinished basement, attic, or garage, read the markings on the cable jacket: aluminum cable is marked "Al" or "Aluminum" every few feet. If it also says "CU-clad" or "Copper-clad," it's copper-coated aluminum, which the CPSC's repair advice doesn't cover. The InterNACHI Standards of Practice require inspectors to report solid aluminum branch wiring when it's readily visible.

Why It Matters

The danger is at the connections. The CPSC has investigated numerous fires involving aluminum branch circuit wiring, at outlets, switches, junction boxes, and appliances such as dishwashers. It explains that aluminum connections deteriorate in ways that raise their resistance, the damage is cumulative, and the resistance causes overheating, sometimes at hazardous levels. In a national survey by the Franklin Research Institute for the CPSC, homes built before 1972 and wired with aluminum were 55 times more likely than copper-wired homes to have one or more wire connections at outlets reach "Fire Hazard Conditions" (cover-plate screws reaching 300°F, sparks, or charring). The survey covered only connections at outlets, not the other aluminum connections and splices that are also prone to fail, and no information was developed for aluminum-wired homes built after 1972.

There may be no warning. The CPSC says failing aluminum connections and splices have been reported to overheat without any prior signs. When there are signs, they include outlet or switch cover plates that are hot to the touch, flickering lights, circuits that don't work, and the smell of burning plastic at outlets or switches. If you notice any of them, have a qualified electrician find the cause promptly.

What to Do Before Closing

• Ask the inspector where they saw it, whether any outlets or switches felt hot or looked damaged, and whether there were signs of an earlier repair.
• Have a licensed electrician evaluate the whole house: how much is aluminum, the condition of the connections, and whether any earlier repair used a method the CPSC recommends. Get a written scope. The CPSC says every aluminum connection and splice in the home should be repaired, including outlets, switches, dimmers, light fixtures, appliances, and junction boxes.
• Talk to your real estate agent about a repair or a credit within your inspection contingency.

What to Do After You Move In

If it wasn't remediated before closing, the CPSC recommends a permanent repair, and it highly recommends hiring a qualified electrician to do it. As of its 2011 publication, the CPSC approved only three permanent repairs:

1. Rewiring with copper. Replacing the aluminum branch wiring removes the cause. The CPSC calls it the best method available, but notes that for many homes it's impractical.
2. COPALUM. A short copper wire, or pigtail, is joined to each aluminum wire end with a COPALUM crimp connector, made with a dedicated power tool. The CPSC considers it a safe and permanent repair, proven by more than a quarter century of field experience; only electricians trained by the manufacturer may install it.
3. AlumiConn. If COPALUM isn't available, the CPSC says the AlumiConn connector, a setscrew-type pigtail connector, may be considered the next best alternative. It performed well in initial tests but, as of 2011, was too new to have COPALUM's long-term record. A qualified electrician should install it.

The CPSC recommends against other fixes. In its testing, substantial numbers of twist-on connectors used for pigtailing overheated severely, and the CPSC says some such "repairs" may fail even more often than the original connections. No other crimp connectors have been evaluated for joining copper and aluminum, and the CPSC strongly recommends against them. Outlets and switches labeled CO/ALR, made for aluminum wire, perform better than ordinary devices when installed carefully but have failed in laboratory tests under simulated real use, and they don't exist for every part of the system, so the CPSC calls them at best an incomplete repair. The CPSC says AL/CU-rated twist-on pigtails or CO/ALR devices may be used only as an emergency, temporary repair for a failed connection, followed as soon as possible by a complete repair using one of the approved methods.

Until the repair is done, keep working smoke alarms that can be heard in the bedrooms and test them monthly, as the CPSC advises (see our smoke and CO alarm guide), and call an electrician promptly for any warning sign above.

Can You Fix It Yourself?

No. The CPSC's own words: if you notice signs of a problem, have a qualified electrician determine the cause, and "DO NOT TRY TO DO IT YOURSELF. You could be electrocuted, or you could make the problem worse." Don't swap outlets or switches on aluminum wire, either: Leviton's GFCI instructions, for example, say not to use that GFCI with aluminum wire. Our DIY vs. hire-a-pro guide lists aluminum wiring as electrician-only work.

Frequently Asked Questions

Is aluminum wiring a deal breaker?

Not automatically. The CPSC's position is that aluminum wiring can be replaced or repaired to effectively and permanently reduce the possibility of fire. What matters is the electrician's written scope, since a whole-house repair touches every outlet, switch, fixture, appliance connection, and junction box; get it before your contingency deadline.

Does the aluminum cable to my range, dryer, or main panel count?

That's a different case. The CPSC's repair recommendations cover the small 15- and 20-amp branch circuits and don't apply to the larger aluminum wire used for service entrance cables, electric dryers, and ranges. Ask the electrician to look at those connections during the same visit. For other findings, see our inspection report decoder.

The Bottom Line

Single-strand aluminum branch wiring from 1965 to the mid-1970s is a fire risk at its connections, and failing connections may give no warning. Have a licensed electrician evaluate the whole house before closing and repair it with one of the three permanent repairs the CPSC approves: copper rewiring, COPALUM, or, where COPALUM isn't available, AlumiConn; not twist-on pigtails or CO/ALR devices. Never work on it yourself.

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