My wife and I are building a new house and I have a question about the entence cable for the power coming into the house. Is it aluminun or copper? This cable comes from the transformer to the house. I'm trying to decide whether to run alum. Or copper from my outside meter to my inside panel.

The wire is usually aluminum. Copper is more expensive, corrodes less and is more conductive.

There was a recent discussion here which had two sides:

1. Inside the house is all copper, not including service entrance
2. Inside the house is copper except high current appliances like stoves and service cable.

Lugs, etc, have to be rated for Aluminum use. An anti-oxidation paste is also used.

Driven by cost and code (AHJ Authority Having jurisdiction) in your area.

Explain wiiring a 3-way switch