Not all aluminum wiring is problematic

Q: Last week, I installed a new circuit breaker in my electric service panel. While doing this, I noticed that the 220-volt circuits are wired with aluminum. Unless I'm mistaken, aluminum wiring is a serious fire hazard. What concerns me most is that this was not disclosed when I bought the house, not even by my home inspector. I've written some hot letters to the sellers, their agent, and the inspector, but would like your opinion before mailing them. Do you think I should make them pay to rewire these circuits?

A: Not all aluminum wire issues are subjects for concern, so cool off and discard the angry correspondence. Aluminum wiring, when used for 110-volt circuits, is known to be a fire hazard, but aluminum is still commonly used for 220-volt circuits. When installed according to manufacturers' specifications and in accord with applicable code requirements, aluminum wires present no significant fire hazard. In fact, most electric power companies use aluminum for their main service lines.

There are two primary rules governing the proper use of aluminum wires:

1) The connecting terminals must be rated for aluminum wiring;

2) The wire ends should be treated with a special compound to prevent corrosion.

Aside from the aluminum wire issue, your reference to having installed a new circuit breaker in your service panel is a matter of concern. Your lack of familiarity with electrical requirements indicates that you should delegate repairs of this kind to the practiced hands of a licensed electrician. It would be wise to have your handy-work reviewed by a qualified professional just to be on the safe side. You can also have the aluminum circuits checked to be sure they are safe as well.

Q: Before buying my home, I hired a home inspector to check out the construction and general condition. He found several defects, most of which the seller agreed to repair. But after closing escrow, I found a problem that was not reported by the seller or the inspector. The exhaust hood above the kitchen range was never vented to the outside of the building.

A: Exterior venting above a kitchen range is such an old and established practice that it is commonly assumed to be a requirement of the building code.

Unfortunately, that is not the case. The code requires exhaust hoods for commercial ranges only. For residential kitchens, there is no requirement for hoods or venting systems. Vented exhaust hoods are obviously preferable, but the lack of a requirement leaves the decision up to the builder.