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About the House The Dangers of Aluminum Wiring in Your Home By MATT CANTOR

Friday March 10, 2006

Once again, cheapness costs lives. This time it has to do with the skyrocketing cost of copper in the 1960s. If you’re my age, which I’m not going to reveal, you may remember when copper shot way up around 1965. Metal futures were all the rage and wire makers were freaking big time. Nobody wanted to pay twice the price for wire, but buildings had to be built, added onto or rewired. 

So aluminum was the solution. It was known even at this time that aluminum was a poor conductor when compared to copper but it was assumed that the difference was negligible (at least that’s what the marketing department told the legal department) and that aluminum would do the job until copper came down in price. 

What the manufacturers, the electricians and the public didn’t know was that aluminum wiring (especially the first generation made between 1965 and 1972) was going to end up causing a lot of fires. The early wiring is considered by the Consumer Product Safety Commission to be 55 times more likely to cause a fire than copper wiring. The later aluminum alloy is somewhat less dangerous but I can’t find any figures on just how much less scary it’s supposed to be. 

So what’s going on with aluminum wiring? Why does it cause more fires? It has to do with two effects, thermal expansion and oxidation and it looks like the oxidation is the more serious culprit.  

When wires have electricity running through them, they heat up somewhat. In fact, a basic principle in wiring is to size the wire as well as the switches, outlets and lamps so that they don’t overheat. A tiny amount of heat is OK, but toaster-hot or waffle-iron-hot is clearly not a good thing because these wires are running through the walls of your house and can start a fire if they get too hot.  

When wires are well connected to one another the power flows nicely through the system. When there’s something constricting the flow, the power tries to jump over the gap or heats up at the point of marginal contact and can actually start melting metal or plastic or throwing off sparks. 

This sort of resistance is the thing that makes the little wires in the toaster glow and look what that can do. Aluminum connections are more apt to have these things happen as a result of those two effects.  

Thermal expansion with aluminum wire is so great that it can push the contact screw outward as it heats up and then leaves a gap as it cools down. That gap can become one of the areas of poor contact that causes sparking and leads to a fire. It can also create a gap at a connection with another wire inside of a junction box, even when a tightly bound “wire nut” is holding them together. 

The other effect, oxidation, begins to occur as soon as the aluminum wiring is stripped for installation. Aluminum oxide is a really good insulator (unlike the corrosion that occurs on copper) and over time can cause the resistance at a connection to get high enough to make a nice little electric heater out of an outlet. 

One way to know that you have a problem is that you may actual smell burning plastic at an outlet or switch. If you see sparks, charring or hear sizzling, this is a very bad sign. If an outlet or switch feels warm to the touch you may be feeling the effects of aluminum wiring. If you’re experiencing any of the above or seeing lights dim when you operate small appliances, you may have aluminum wiring (although other electrical deficiencies can cause this as well). 

The only way to be sure that you have or don’t have aluminum wiring is to have someone (such as an electrician or building inspector) look and see. 

Aluminum is still used for very large “feeders” and seems to function well for these. They may be the main wires leading from your outside panel to an inside panel or the “dedicated” wiring to the stove or dryer. Wiring leading to outlets and switches should not use aluminum if at all possible and you may want to simply replace it with copper, cutting and abandoning the old wiring in the walls. 

An alternative is to have a certified installer place “Copalum” connectors in every junction box of the house that uses aluminum. This is the only method that the Consumer Product Safety Commission sanctions other than replacement of wiring. 

It’s not cheap either but it’s probably a lot cheaper than replacement, especially if you live in a two-story house. It’s also a lot cheaper than the tragedy of a fire, whose expense may not be measurable in dollars. 

If you have aluminum wiring from after 1972, it’s a little safer because the wire alloy was changed and the devices (outlets, switches, etc.) were improved. I’d still be very concerned if it were my house. Aside from having kids, I’m just plain afraid of fire. 

While the data is sketchy, there are some nasty news reports. The Pittsburgh Channel reports that 165 people were killed at the Beverly Hills Supper Club in Kentucky in 1977 as a result of aluminum wiring. A fire in New Jersey in 2001 killed a family of five including 3 children. Aluminum wiring was blamed. 

These aren’t the only stories I’ve found but it’s so unpleasant that I think I’ll stop there. We may have to wait a few years to have better data, but the scientific research is very clear that fires start much more easily with aluminum branch wiring than with copper. 

Wiring is not the most expensive thing in your home to fix or upgrade and electrical fires are anything but rare so it’s worth taking action if you have aluminum. If your house was built prior to 1965 or after 1973 and wasn’t rewired or remodeled, you probably don’t have any. If you’re not sure, have someone check. 

If you have determined that you have aluminum wiring leading to your outlets and lights and you want to go the Copalum connector route, you can contact Tyco at (800) 522-6752. Only certified Copalum installers can put them in and if you want to know more, the CPSC can send you a copy of Repairing Aluminum Wiring by writing to them at CPSC, Washington, DC 20207. 

And may only your thoughts and your heart be warm tonight.