If your house was built between 1965 and 1972, you may have a disaster waiting to occur.
While utility companies run aluminum wire overhead and underground in many places, aluminum is not a good choice for lighting or other branch circuits.
Utilities use huge gauge wires to carry power. The power coming into your house may even be on aluminum wire but they would also be quite large.
The problem is that the wires in your house are small: 12 for lighting; 10 for bath, dining and kitchen receptacles, 8 for water heaters and dryers. (These are aluminum sizes. Copper sizing runs 1 gauge smaller. )
Aluminum has more resistance than copper. More resistance means more heat. More heat means more expansion and shrinking.
The insulation used back then was less pliable than that used today and over time becomes brittle due to heat.
The photo above shows a receptacle where the insulation had completely deteriorated and fallen off a 2 ½ inch section of wire. This is a fire hazard.
Aluminum wire is almost always run into a metal box. An exposed wire touching the metal box can arc and start a fire.
So what to do?
When we are doing a remodel, we always replace aluminum wires. But that can be quite expensive.
A less expensive stop-gap is to install AFCIs in your panel.
Arc Fault Circuit Interrupters "listen" to a circuit and when they "hear" an arc they trip.
We install these quite a bit in these older homes.
In new homes, AFCIs are required by code in many places in habitable spaces. They are not required in garages and unfinished basements.
One thing to remember, though, is that if you have any breaker that trips, you need to find out why and have it fixed. Continually resetting a breaker can cause it to malfunction and quit tripping at all.
