Question, is it an issue if 240v 2 pol breakers are using aluminum wire? I think its done because of cost, am I write?
Up to 30 amps I normally see copper. Higher than that either aluminum or copper stranded normally.
Yes, I think you are right.
as long as it’s multistranded wire and sized correctly it is not a problem, and yes it is cheaper.
I do not know how to check but I think the bkr better be rated for Au
Good point Richard,
the breaker will be marked CU/AL if suitable for both, though many times you can’t see it due to the breaker being obscured by other breakers.
In no way am I an electrical guru. Far from it.
But I will try to answer your question.
The problem with aluminum wiring is with the 120 volt circuits. The solid wire tends to expand and move out from the wire.
Stranded aluminum in larger gauges is considered safe.
Also the connections need to be properly fitted with copalum connectors.
I see a lot of copper clad aluminum and tinned coated copper in this area.
I am sure the electrical gurus will correct me if I am wrong.
The real way to look at aluminum is to look at the terminal, not the wire, strands or whatever. If this is a “silver” (aluminum alloy) terminal with a set screw trapping the wire in a hole, it will probably last forever, assuming it was torqued properly, black goo or not.
The real problem was wires wrapped around a screw, particularly a steel screw (pre CO/ALr) on the typical “box” device. Most of the problems went away when the CO/ALr devices started using a bronze screw with a better match in linear expansion. By then, there was enough trouble to doom the product.
Aluminum actually performs as well or better than copper in the aluminum alloy terminal you see in panels and large breakers.
The electricians around here only have problems with the 15 and 20-A circuits with single-strand aluminum. In my early days I found some 30-A and 40-A circuits with single-strand aluminum, and the electricians didn’t have any problem with that, nor with any multi-strand aluminum.
How could you have single strand 30 and 40a circuits? 8Ga and larger in cables or pulled through raceways must be stranded?The aluminum problem is not “solid” conductors. It is the type of terminal. Steel binding screws, as found in the typical 15/20a device and aluminum wire don’t mix well.
I find them in homes from the mid-1970s to the mid-1980s. Perhaps they were allowed then? I don’t know; I only know that the electricians don’t have any problems with the larger single-strand aluminum wiring.
Everything that I’ve read indicates that aluminum single-strand wiring is problematic. Not whether or not that problem comes from the type of terminal used to attached that single-strand aluminum wiring, I don’t know. But my E&O insurance and real estate attorneys require me to call out any single-strand aluminum wiring in 15A and 20A circuits. That’s good enough for me.
The connections weren’t adequate.
This may be helpful:
Whatever works for you…
I am just pointing out what the real problem is.
I’m familiar with that site. I reference it in my reports when I find single-strand aluminum wiring in 15A and 20A circuits.
The first paragraph says it all for me as a generalist home inspector:
I also agree. NACHI is so agreeable. You should join us, Greg. We really are an agreeable bunch around here.