Solid Strand Aluminum Wiring

[HRInspector]

Looking for some clarification regarding solid strand aluminum wiring.

Part most home inspectors SOP is this statement:

J. and report the presence of solid conductor aluminum branch circuit wiring, if readily visible
​

So when many home inspectors see any solid strand aluminum they call it out for review.​

It's my understanding is that the aluminum wiring that was in question was installed back in the late 60's - 70's on 15-20 amp branch circuits.

The disagreement I am having with some other home inspectors is regarding solid strand aluminum that was installed well after those dates to the present. I see solid strand being used for dedicated 30 amp circuits. I do not call it out, but I am being told that it should be.

I am in no way a code guy but looking at 310.14 solid aluminum conductors are listed. I see no reason to be calling this out for review, but figured I would get the thoughts from the experts. Any clarification would be appreciated.​

 

[ActionDave]

Looking for some clarification regarding your terminology of what you mean by "solid strand aluminium wiring", but I think you are on the right track concerning it.

10 and 12AWG AL wire on switches and recpts not listed for AL = bad.

Larger sizes that land on lug = probably ok.

​

 

[hurk27]

Back in 1976/77 when the copper mines went on strike in South America which pushed up prices on copper here, I can remember the push to use aluminum wire, but the company that I was working for at the time didn't and we kept installing copper.

The problem was it was rushed into the market and not much was known about how to do the terminations, and I can't remember if any wiring devices were even listed for ALU or even required?

Not many electricians much less inspectors back then even knew much about how to make proper connections and this was the main failure point.

There is not really nothing wrong with using aluminum wire and it is even still to this day allowed by the NEC and UL but under more strict guide lines.

The problem is with the terminations, and very few device manufactures make AL listed devices, P&S does and is available around here.

Aluminum terminations require special considerations as it can expand and contract much more then other metals as temperature changes, this can cause what is called cold flow of the conductor out from under fixed screws and terminals, so if the terminal or screw is made of a different metal then there needs to be a spring loaded washer or clamp that will allow the aluminum to expand and contract without the connection loosening up, this is not a problem in which aluminum lugs or terminals are used, the other problem is corrosion, the newer alloys have solved most of this but in a high moisture environment it can still be a problem as I have witnessed.

Most buildings that have aluminum wiring can be fixed if there is a problem, but it takes someone who knows what to look for to know if there even is a problem, we have a whole neighbor hood with all aluminum wired houses and some are in very good condition and have never had a problem, but there are many that were wired by installers who didn't know how to use aluminum or make proper connections and there have been failures.

I'm in the middle of doing one now, a 1978 two story colonial, all the 20 amp circuits were wired with 12/2 instead of 10/2 AL NM, the whole house had just 12/2, so to keep cost down I replaced all 20 amp circuits with new copper including the bathroom receptacles, and will replace all devices with P&S AL/CU listed devices, all AL connections will get AL listed wire nuts with the grease in them, all lights and any other outlets will be checked, even though Indiana doesn't require AFCI's the owner wants them, so a new Square D HL will be installed with AFCi's on any circuits left with aluminum conductors, while I have my doubts about the AFCI detecting and series arcs, at least a fault to ground will be lessened.

So yes this house will still have some 15 amp lightly loaded circuits with aluminum, but it will be safe when I'm done with the job.

Most HI's around here will only remark that aluminum was found and needs to be checked by a qualified electrician experienced in aluminum wiring, and I get many of these calls, they do not cast any judgment on it as most have no idea what they are even looking for.

Remember it was legal then as in (grandfathered) and still is legal now (if installed correctly)

Now would I buy a house with it? Nooooooo
It would never get fixed LOL

 

[hurk27]

Also I noticed you mentioned a 30 amp circuit having solid aluminum conductors, for one a 30 amp circuit would require #8 for the wire size, and I don't remember any #8 as being solid? this sounds like it is a #10 which is only good for 20 amps and might be a flag to someone who didn't know how to size aluminum conductors, all 20 amp circuits would or should have #10, and 15 amp circuits would be #12

If this is not the case then you have other problems that need to be flagged, I'm mentioning this because the house I posted about that I'm in the middle of doing had #12 to all the kitchen circuits and 20 amp well circuit, no AC system but a old unused dryer receptacle had #10 to it which was not rated for a 30 amp dryer, since the new owners have a gas dryer it was removed.

 

[don_resqcapt19]

Back in 1976/77 when the copper mines went on strike in South America which pushed up prices on copper here, I can remember the push to use aluminum wire, but the company that I was working for at the time didn't and we kept installing copper.

...

Wayne,
Are you sure about the time frame? The new alloy aluminum came out in 73/74 and was not in the market very long. They also put the CO/ALR devices into the market when the new alloy aluminum was brought out. I thought, for the most part, the #10 and #12 aluminum was already off the market in 76/77.
We did an appartement complex with the new alloy stuff in 74/75 along with the CO/ALR devices, but that is the only time I ever worked with small aluminum. Note this was individual conductors, I have never seen aluminum NM around here.

 

[mlnk]

In 1965 NM Aluminum in #12 and #10 came on the market. I thought it was due to so much copper being used in the Vietnam War in addition to mining/supply problems. Over the next 10 years about 2 million homes were wired with AL NM. Lots of fires have occurred in these houses. Re-wiring is the best solution, but is expensive. One solution is to pigtail copper onto the AL with special CU/AL connectors, then use standard switch and receptacle devices for copper wiring.

 

[don_resqcapt19]

In 1965 NM Aluminum in #12 and #10 came on the market. I thought it was due to so much copper being used in the Vietnam War in addition to mining/supply problems. Over the next 10 years about 2 million homes were wired with AL NM. Lots of fires have occurred in these houses. Re-wiring is the best solution, but is expensive. One solution is to pigtail copper onto the AL with special CU/AL connectors, then use standard switch and receptacle devices for copper wiring.

That would have been the old alloy aluminum. The new stuff hit the market in 73/74 along with the CO/ALR devices. The CO/ALR devices have aluminum back plates and screws for the terminations to closely match the thermal expansion and contraction of the aluminum conductor. The older devices had steel screws and the thermal expansion of the aluminum conductor is much greater than that of the steel screw. The resulted in the aluminum being extruded out from under the screw when the connection heated up. Over time this resulted in a very poor connection and excessive heat. The high resistance of the connection limited the current so the OCPD did not see an over load, but the current flow from the load across the high resistance connection produced enough heat, in some cases, to start a fire.
The problems and reputation of older aluminum doomed the new stuff.