Aluminum wiring in Baton Rouge homes is easy to miss, because from the outside the cable in your wall looks like the same plastic-sheathed Romex that is in every other house on the street. The Consumer Product Safety Commission says aluminum cable has no readily discernable distinction from copper cable. That is why so many people find out from an inspector, a burning smell, or a buyer's electrician.
Aluminum branch circuit wiring went into houses all over the country during a short window, and plenty of those houses also have two-prong outlets with no ground. Having aluminum is not the main concern. The condition of the connections is.
Where it came from
A copper shortage in the mid 1960s pushed builders toward aluminum. It was already in use on the big circuits, like the range and the dryer, and from about 1965 through the mid 1970s it also went into the ordinary 15 and 20 amp circuits that feed outlets and lights. The CPSC's guide, Repairing Aluminum Wiring, lays out that history.
The CPSC's figure gets quoted constantly, usually without its limits. A survey done for the CPSC found that homes built before 1972 and wired with aluminum were 55 times more likely than copper-wired homes to have at least one outlet connection reach "fire hazard conditions." The survey defined that as a receptacle cover plate screw reaching 300 degrees, sparks coming from the receptacle, or charring on the material around it. Two limits matter. The survey looked only at connections at outlets, not splices in boxes, which the CPSC says are also prone to fail. It also produced no information on aluminum-wired homes built after 1972.
The CPSC says homes built before 1965 are unlikely to have aluminum branch wiring. If yours was built, added onto or rewired between 1965 and the mid 70s, it is worth ten minutes to check.
Why the connection is the problem
The CPSC describes several deterioration processes at aluminum connections that raise their resistance to current. More resistance means more heat at the connection, and the damage builds over time. Aluminum also expands and contracts more than copper as it heats and cools, which can loosen a screw termination, and it forms a surface oxide that resists current. Each of those makes the next one worse.
What makes this different from a broken wire is that it gives little warning. In the CPSC's words, failing aluminum connections seldom provide easily detected warning signs, and some have overheated with no prior sign of trouble.
How to find out what you have
The cable jacket is marked every few feet, and on aluminum cable the marking says Al or Aluminum. Most houses around here have no basement, so look where cable is exposed: the attic, the garage, or near the panel. Shine a flashlight across the jacket at a low angle. Straight on, embossed lettering is hard to read.
One trap catches people. If the jacket says Cu-clad or Copper-clad along with Al, the wire is copper-coated aluminum, and the CPSC repair guidance does not cover it.
If you cannot find a marking, an electrician can identify the wire for you.
What the repair actually is
The CPSC approves only three methods as a permanent repair, and it names a few others that are not. From best to worst:
- Replace the wire with copper. The CPSC calls this the best method available. It is also the reason nobody leads with it: it often means opening walls.
- The COPALUM crimp. A short copper pigtail is joined to the aluminum with a special connector, which a dedicated power tool crimps into what amounts to a cold weld. The CPSC considers it a safe, permanent repair. Only electricians trained by the manufacturer are authorized to install it, so it is not available everywhere.
- The AlumiConn setscrew connector. The same pigtail idea, using a setscrew connector instead of a crimp. The CPSC calls it the next best permanent repair when COPALUM is not available. It notes the connector performed well in tests but has a shorter track record.
- CO/ALR devices. Outlets and switches rated for aluminum. They fix the device end but not the splices, and they do not exist for things like hardwired appliances and ceiling fixtures. In the CPSC's words, they are at best, an incomplete repair.
- Twist-on connector pigtails. In CPSC-sponsored testing, substantial numbers of these overheated severely, and the CPSC says this method does not solve the problem. An AL/CU-rated twist-on is acceptable only as an emergency, temporary fix for a connection that has already failed, with a complete repair to follow as soon as possible. The CPSC also strongly recommends against any crimp connector other than COPALUM, including the hand-crimped kind sold at hardware stores.
Keep that list handy, because "we pigtail aluminum wiring" can mean several different jobs with different outcomes. Only two of the pigtail methods meet the CPSC's standard for a permanent repair. A proper repair also covers every aluminum connection in the house, not just the outlets that are acting up.
One more thing catches people. Aluminum and copper are sized differently for the same job. A Number 12 aluminum conductor goes on a 15 amp circuit, while Number 12 copper goes on a 20 amp circuit. Someone who reads the wire gauge with copper in mind can end up putting a breaker on that circuit that is too large for the wire.
Two-prong outlets and ungrounded circuits
Houses from this era often have a second issue alongside the aluminum: two-prong outlets with no ground wire behind them. Swapping in a three-prong outlet without a ground is not a fix. It just makes the outlet look grounded when it is not.
The code gives three legal options when there is no ground in the box (section 406.4(D)(2)):
- Replace it with another two-prong outlet.
- Replace it with a GFCI outlet marked No Equipment Ground.
- Install a three-prong outlet that is protected by a GFCI upstream, marked both GFCI Protected and No Equipment Ground.
A GFCI still protects people on a two-wire circuit, because it does not need a ground wire to sense leaking current. What it does not do is create a ground. Anything that relies on a ground connection still does not have one. Running a new ground wire, or new circuits, is the full fix.
On an aluminum circuit there is one more step. The outlet has to be rated for aluminum, or the aluminum has to be properly pigtailed to copper first using one of the CPSC methods above. Putting a GFCI on bare aluminum without that step brings back the connection problem this whole post is about.
Signs it is already going
The CPSC lists hot face plates on outlets or switches, flickering lights, circuits that stop working, and a burning-plastic smell at an outlet or switch. If you notice any of these, stop using the circuit and have an electrician find the cause.
Do not open the box to look for yourself. The CPSC is blunt about it: do not try to do it yourself. You could be electrocuted, or you could make the problem worse.
Common questions
Does aluminum wiring make my house uninsurable? Not on its own, and it is a different conversation from an old panel. Some carriers ask about it, some want documentation that the connections were properly repaired, and some never bring it up.
Is a pigtail enough? It depends on which kind. A COPALUM crimp or an AlumiConn connector at every aluminum connection is a permanent repair by the CPSC's standard. A twist-on connector is temporary at best.
Can I do this myself? We would rather you did not. The failure to worry about is a connection that looks fine on the day it is made and heats up a couple of years later. The CPSC recommends a qualified electrician for every repair method it approves, and COPALUM requires a trained installer.
If your house went up in the late 60s or 70s and nobody has ever checked the connections, call us. We will tell you what is in there and what, if anything, it needs. In Gonzales and around the area, the answer depends on how many connections there are and what shape they are in, and we can tell you that after one look.