History of Aluminum Wiring

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Questions for for my old-timer electrical friends - Has Aluminum wiring ever been used as a feeder to a 100- amp service in buildings? Branch circuits? If so, at what time period? Would that be safe today?
 
I'm a new timer and yes and from the 60s on. Also aluminum is still allowed for branch circuits its just needs to have proper connections and no one makes 10awg or smaller aluminum excluding copper clad but that's a different material completely. For feeders over 40 amps it is very common in new installations.
 
Seems like around 1970ish aluminum NM cable was very popular for branch circuits. I believe the smallest they made it was #12 and that was rated for 15 amps. When I see it I always picture grandma plugging a space heater into it and perishing in a fire.

It's kind of like K&T, more or less safe if it's done right and in good condition, but most times I see it, it's been butchered up.
 
Joethemechanic said:
Seems like around 1970ish aluminum NM cable was very popular for branch circuits. I believe the smallest they made it was #12 and that was rated for 15 amps. When I see it I always picture grandma plugging a space heater into it and perishing in a fire.

It's kind of like K&T, more or less safe if it's done right and in good condition, but most times I see it, it's been butchered up.
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Knob and tube is safer people just end up ruining the switched nuetrals and give up. Aluminum will kind of sort of work till catastrophic failure. Knob and tube is in metal boxes surrounded by air or protected at 15 amps the Aluminum is in busted up fiberglass boxes in cellulose non fire treated insulation and on a full 20 amp legal breaker.
 
Yeah switched neutrals and those carter 3 ways that switched the polarity of the light. I've even come across quite a few where both hot and neutral were fused. They looked original to the installation. Not sure why they thought that was a good Idea
 
Joethemechanic said:
Yeah switched neutrals and those carter 3 ways that switched the polarity of the light. I've even come across quite a few where both hot and neutral were fused. They looked original to the installation. Not sure why they thought that was a good Idea
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The switched nuetrals made sense when you wanted to minimize shock hazard and didn't want to pull the fuse while working you could just not have a bulb in the fixture and be good to go even if standing on the water pipe in wet socks. The carter's were hated from the beginning otherwise they'd have lived into the 40s instead of being gone in the 20s.
 
Was the 12 gauge aluminum NM rated 20 amps? I seem to remember you had to use one size larger, but that could have just been "good practice" by the old timers I grew up around
 
Joethemechanic said:
Was the 12 gauge aluminum NM rated 20 amps? I seem to remember you had to use one size larger, but that could have just been "good practice" by the old timers I grew up around
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No the 10 awg that was still back stabbed after drilling the hole bigger into the outlets. It's always been sized that way the only upside has been 10 awg is good for 25 amps at 60° vs 20
 
letgomywago said:
No the 10 awg that was still back stabbed after drilling the hole bigger into the outlets. It's always been sized that way the only upside has been 10 awg is good for 25 amps at 60° vs 20
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Backstabbed aluminum wire in a modified device. That sounds like grandma, grampa, a cat and a puppy all perishing in a fire
 
letgomywago said:
Why do you think it only took like 5 years to stop using the alloy?
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I seem to remember there being two different aluminum alloys used. But yeah it seemed to get a bad name quickly.

After Hurricane Agnes in 72 my cousin lost her home and had to live in a HUD trailer. I seem to remember them being all aluminum wire. Those trailers had a reputation of being fire traps
 
Make that three or four different alloys,,,

Early was AA-1350

The first 8000 series electric conductor alloy, still widely used in some applications, was developed and patented in 1972 by Aluminum Company of America (Alcoa).[8] This alloy, along with AA-8030 (patented by Olin in 1973) and AA-8176 (patented by Southwire in 1975 and 1980), performs mechanically like copper.
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Something that also gave aluminum a bad name, is people would stick copper up under it and cause the connection to fail. Especially mobile home disconnects, the water well people would shove a #10 copper up under the same lug as the 4/0 aluminum.
 
Interesting. We, in UK, rarely encounter aluminium. I'm sure we must have seen some but my experience was limited to a couple of anodising plants. My most recent was with a 40,000A DC 35V water cooled system.
 
Joethemechanic said:
Seems like around 1970ish aluminum NM cable was very popular for branch circuits. I believe the smallest they made it was #12 and that was rated for 15 amps. When I see it I always picture grandma plugging a space heater into it and perishing in a fire.

It's kind of like K&T, more or less safe if it's done right and in good condition, but most times I see it, it's been butchered up.
Click to expand...
I worked Saturday mornings re-stocking the local electrical contractor's trucks when in High School, and seem to remember AL making an appearance about 1966 in the St. Louis area.

And yes, the electricians usually went 'one size up' compared to copper.
 
Joethemechanic said:

I believe aluminum wire was ruled to be the official cause of this fire. Lots of fatalities
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I don't think aluminum wire, in and of itself, could have caused the fire; the way it was installed seems a more likely culprit to me. There were characteristics of aluminum that were not well enough understood at the time, but had they been known and taken into account it likely could have been safely used.
 
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