Does anyone remember what year the NEC allowed aluminum conductors for branch circuits in residential wiring? I recently had a service call to a condo complex in Cromwell CT, and all the units were wired in AL. The water heater wired with a #10 al on a 2 pole 20. Inspector made us change it to a #10 cu.
Aluminum wire
- Thread starter Mr. M
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mike7330
Senior Member
- Location
- North America
I work with aluminum and copperclad romex in 1970, so it was in the code at that time. I feel so old now?
jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
When was it not allowed?
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Never, been allowed in every code book I have, but can be a local rule and I know some insurance company's who will refuse to insure a house with aluminum branch circuits.
While some will say that no receptacle manufacture makes a receptacle that is listed for AL, I was in the store the other day and low and behold there was a whole shelf of receptacles with the AL/CU marking on them I think P&S
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
If it is a 4500 watt element then all you needed to do was changed the breaker to a dp 25 amp.
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
thank you, just because of the problems of the 70s, people have a misconception that it was banned.
resistance
Senior Member
- Location
- WA
Heck, as high as gas prices are getting, we may have to start using it in smaller gauges. 
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Try and wire a house with aluminum and see what happens.
I would be surprised if anyone made aluminum in those sizes.Try and wire a house with aluminum and see what happens.
I have heard nobody is manufacturing NM AL 10 or 12 AWG cable, so the only way to do it would be to find enough NOS, New Old Stock, AL NM but since current NEC requirements call for 90C ratings, it would be a no-go IMO for that reason alone.
Rock Crusher
Member
- Location
- Ne. USA
I always found it funny how people say that AL is crap for house wire, or it's never used anymore. Although it is not the prefered method of wiring a house and often frowned upon, it would work fine, imo, if sized properly. Same as with feeders; which, incidently, are mostly AL. Why? Cheaper and easier to work with. But, it was sized accordingly.
I'm sure there are a million other reasons not to use it in a house, this was just an opinion.
I welcome corrections and education on the subject.
I'm sure there are a million other reasons not to use it in a house, this was just an opinion.
I welcome corrections and education on the subject.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
The wire size has really very little to do with the failures of aluminum.
While this also goes for copper, almost all wire failures are at the termination point, two of the biggest differences between aluminum and copper is the type of corrosion, when copper corrodes it forms copper sulfide which is conductive, when aluminum corrodes it forms aluminum oxides which is not very conductive, thus as it looses connection from aluminum oxide it starts to heat, till it just melts down, Aluminum oxidizes very easily with just a slightly moist environment, this is where sealing the connection is very effective if the compound doesn't dry out over time, I find a good dielectric grease to be more effective then no-lox because of this.
The other problem with termination is aluminum can cold flow when terminated in a dissimilar metal terminal without any spring to allow expansion, because of the different expansion rates the aluminum will expand faster then the other metal and if there is no spring to give and to maintain a constant pressure like a expansion joint, the aluminum will cold flow out from under the terminal so when it cools you no longer have a tight connection, many terminals had a spring clip/plates that was tightened down on the conductor, but today very few terminals are made like this, never understood why? as this problem happens with larger terminals and conductors also, so I try to only use aluminum conductors where the terminals are also aluminum or have the spring tension clips/plates, and use dielectric grease.
The problem with branch circuit wiring is, to do the job properly will make the cost and labor of it not worth what you would save using it.
And the fact it would be hard to find in small AWG's as well as that many insurance companys refuse to insure a house with small branch circuits wired with it.
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- Location
- Illinois
- Occupation
- retired electrician
The old alloy aluminum that was used before 1973 or 74 had serious problems. The newer alloy that was used after that date, had no real problems as long as you used it with CO/ALR devices. One of the major differences is that those devices have aluminum termination screws so the wire and the screw expand and contract at the same rate reducing the cold flow problem. The typical wiring device used in residential had steel screws and when they are used with aluminum, especially the older alloy there was a very serious cold flow problem. As the information about the fires caused by the older aluminum became more widely know, people moved away from the use of aluminum for the 15 and 20 amp branch circuits and I don't think there is any aluminum in those sizes on the market now.
I was an apprentice when the new alloy aluminum came on the market and there was a copper price issue then too. We did a couple of projects with aluminum and after I topped out, I ran a service truck for a few years. The aluminum projects had no more service calls than did our projects wired with copper, with one exception. One building had the roof blown off in a storm and the inside got wet. After than we had some additional problems on the top floor of that building...mostly with wirenut connections that had the open end up and water had collected in the connection. I expect that even a copper connection would experience additional problems under those conditions. To this day, I don't install wirenuts with the open part up, even when they are installed in a normally dry location.
I was an apprentice when the new alloy aluminum came on the market and there was a copper price issue then too. We did a couple of projects with aluminum and after I topped out, I ran a service truck for a few years. The aluminum projects had no more service calls than did our projects wired with copper, with one exception. One building had the roof blown off in a storm and the inside got wet. After than we had some additional problems on the top floor of that building...mostly with wirenut connections that had the open end up and water had collected in the connection. I expect that even a copper connection would experience additional problems under those conditions. To this day, I don't install wirenuts with the open part up, even when they are installed in a normally dry location.
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jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Try and wire a house with aluminum and see what happens.
I have never even seen a house with small gauge AL circuits, let alone worked with it. I have never touched K & T either.
My point was that it would be legal and that existing circuits are not automatically banned and illegal.
Yes, I know that there were many problems with this method.
I have heard that AL NM was used around 1970 +/- a couple of years. I have done repair work to houses with AL wire and have seen both scenirios, the wire in great shape and burned and unusable.
I had heard (Rumor-It would be interesting to know) that AL romex came into greater use because of the escalation of the Vietnam conflict. The was a big offensive in about 1968.
I had heard (Rumor-It would be interesting to know) that AL romex came into greater use because of the escalation of the Vietnam conflict. The was a big offensive in about 1968.
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Yeah, it is called the Tet offensive.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
It seems aluminum esp. in the smaller gauges has lost it's ability to come back. Most insurance companies would still frown on it in spite of the fact that the product may be better now than it was then.
Also you would have to wire all your lights in #12 which would not be much fun if you use decora stuff and have to ground switches. Back in those days the devices didn't have a ground screw. Anyway I doubt we will ever see it.
BTW, I never installed it but I have worked on many houses with it- in fact my first house had aluminum wiring.
Also you would have to wire all your lights in #12 which would not be much fun if you use decora stuff and have to ground switches. Back in those days the devices didn't have a ground screw. Anyway I doubt we will ever see it.
BTW, I never installed it but I have worked on many houses with it- in fact my first house had aluminum wiring.
- Location
- Illinois
- Occupation
- retired electrician
Other than the box fill the use of new alloy aluminum was not an issue. The #10 aluminum bends as easy as #14 copper. The jobs I used it on were all conduit jobs and I have never seen aluminum NM.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
That's correct fill is an issue. You install #12 copper with decora switches and I will tell you it is an tight even if the fill is correct. I used to wire with 12 awg exclusively in a house and when we had to start grounding the switches and use decora devices and dimmers I decided 14 awg was better.
K8MHZ
Senior Member
- Occupation
- Electrician
110.5 Says copper only unless specified otherwise. I see no exception to 110.5 for residential branch circuits.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
So are you saying that I cannot have aluminum service cable. Where in 110.5 do you see that aluminum is not allowed for branch circuits.
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