Silly question about Branch Circuit Requirements for Aluminum

[ul_1973_tested]

Hi all,

Long time lurker, first time poster.

I have what is probably a ridiculous question. In the 2023 (and previous) NECs, table 210.24 - Branch Circuit Requirements - Summary has an entry for aluminum and copper-clad aluminum wires.

Is it true that you can wire branch circuits with aluminum wire? Or is that part irrelevant because (a) you couldn't buy NM-B aluminum wire or (b) nobody will insure the house? I'm not planning on wiring a house with aluminum wire, I just didn't understand why it was still in the NEC table and was curious about if anyone ever uses aluminum wire for branch circuits.

Are there any houses that are built in the modern era that use aluminum-only NM-B wire for say a 20-amp branch circuit?

Thanks all!

 

[Dennis Alwon]

There is copper clad aluminum but I have not heard of aluminum in small sizes

 

[petersonra]

Why would they take it out?

There is nothing inherently wrong with aluminum conductors. The fact that it was installed improperly many years ago leading to a relative handful of fires is not the fault of the product but it has received the bulk of the blame.

 

[ul_1973_tested]

Why would they take it out?

There is nothing inherently wrong with aluminum conductors. The fact that it was installed improperly many years ago leading to a relative handful of fires is not the fault of the product but it has received the bulk of the blame.

That makes sense--if you use right connectors and right installation, it's still safe, so stays in the NEC.

I was just wondering if anyone actually uses it in modern homes and if, say, UL-tested 14-gauge NM-B cable is even manufactured.

 

[don_resqcapt19]

That makes sense--if you use right connectors and right installation, it's still safe, so stays in the NEC.

I was just wondering if anyone actually uses it in modern homes and if, say, UL-tested 14-gauge NM-B cable is even manufactured.

As far as I know there are no aluminum conductors smaller than 8 AWG on the market at this time. There was a small window in the mid 70s where you could get the new alloy aluminum in 10 and 12 AWG, but because of problems with the old aluminum, few wanted to buy it, and it was not profitable for the manufacture's to continue making it. There is no code or listing reason why it is not on the market.
There is 12 and 10 AWG copper-clad-aluminum on the market.

 

[mtnelect]

This aluminum requirement all started with HUD (Housing and Urban Development) around 1965, to reduce the cost of low-income housing. If the cities did not change their Building Code to accept aluminum "Romex" they would not get federal funding.

 

[electrofelon]

This aluminum requirement all started with HUD (Housing and Urban Development) around 1965, to reduce the cost of low-income housing. If the cities did not change their Building Code to accept aluminum "Romex" they would not get federal funding.

I don't believe AL branch wiring was ever prohibited by the NEC. Were there lots of jurisdictions that had rules against it?

 

[mtnelect]

I don't believe AL branch wiring was ever prohibited by the NEC. Were there lots of jurisdictions that had rules against it?

I know Los Angeles had to change their code around 1970 to allow it. Same for the unincorporated areas of Los Angeles County.

 

[petersonra]

I know Los Angeles had to change their code around 1970 to allow it. Same for the unincorporated areas of Los Angeles County.

It would be hard to get any taxing district these days to change their codes to allow for more affordable housing. They don't want lower cost hosing because the real estate taxes are less. That's why the trend towards trailer parks with $100,000 trailers in them. I would not be approaching them with the idea of lower costs because that would be exactly the opposite of what they want. Tell them it is somehow green. they will do anything crazy if it is green.

 

[mtnelect]

I did service work in those days and found many homes in the unincorporated areas of Los Angeles County with aluminum "Romex". They all had connection problems, mostly with the devices.

 

[don_resqcapt19]

I did service work in those days and found many homes in the unincorporated areas of Los Angeles County with aluminum "Romex". They all had connection problems, mostly with the devices.

Yes, because the cheap junk wiring devices typically used in those types of projects had steel screws and there is a substantial difference in the thermal expansion/contraction between steel and aluminum and the aluminum would "cold flow" when it expanded under load and over time that resulted in a very poor connection. One of the major differences between the old alloy aluminum and the 8000 series alloy used now is that the thermal expansion/contraction is much closer to that of copper.