My daughter recently bought a 40-year-old house in Ann Arbor Michigan. About half the electrical circuits are wired with copper, and half with aluminum. Unfortunately no one seems to have paid much attention to the type of fixtures installed, most are labeled CU only but have aluminum wire attached, light fixtures have copper pigtails on them connected to aluminum wires with wire nuts. How big of a problem is this? Is it dangerous? Also she has several light fixtures that burn out bulbs every couple of weeks, could this be caused by aluminum wire on copper fixtures? What are the options here, if it was in conduit I’d just yank it all and put in copper but it’s all romex so that won’t work.
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If the pigtailing is properly done (a big if) then the wiring is relatively safe and reliable. Where fixtures are attached without pigtailing, or where copper and aluminum are joined without use of an antioxidant, problems can occur.
Flickering lights would be the most common sign of a problem. Occasionally imperceptable flickering can cause light bulbs to burn out rapidly.
Another cause of rapid light burnout that is likely in a house that age is a poor neutral connection where the main connects to the breaker panel or somewhere back up the service entrance. This can be checked by measuring the voltage at several different outlets around the house (enough that you get on both sides of the 240V line). A voltage difference between outlets of more than a volt or two suggests a problem.
Hazards associated with the aluminum wiring can probably be reduced significantly by installing arc detecting circuit breakers. Unfortunately, this is expensive and there may not be such breakers available for the existing breaker panel.
DanH, thanks for the info, the neutral problem sounds easy enough to check I'll try your suggestion. No anti oxident is used on any connections that I looke at so far.
>>Also she has several light fixtures that burn out bulbs every couple of weeks, could this be caused by aluminum wire on copper fixtures?
That could be an indication of a bad neutral on the main service to the house, which is a major safety concern.
First eyeball the service looking for breaks in the neutral. For a 40 year old house in this part of the country, it is probably a bare wire from the masthead/house connection out to to the pole.
If you find a break or other problem, call the electric company immediately - they'll be out quickly.
Even if you don't find an obvious problem, check with the neighbors, see if they have the same burned out light bulb problem - it could be a problem in the elec co's service affecting more than one house. Call the Elec Co immediately.
Re alum wiring: This is an opinion ----
Carefully clean up, anti-ox and retighten all connections right now.
Be very careful not to overflex the alum.
Start replacing the alum branch circuits with copper: for safety and resale "value"
There were 2 problems with alum branch wiring: the better known one is the problem with deteriorating connections; the other is that the first alum wiring was very brittle and broke with realtively little flexing.
In the one house I've seen with alum branch wiring, (Lamertville MI?) one wire snapped at a bend with a minor push on it in the main box.
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