Why is aluminum wiring so scary?

An older aunt of mine just recently moved into an older condo (row house). She noticed after moving in that some of the electrical is questionable (some light switches/outlets don't work, 1-way switches in a 3-way arrangement, etc).

Most of her issues should be simple fixes, but she has aluminum wiring.
She's been having a tough time finding an electrician that will tough the stuff without paying a premium.

I understand aluminum wiring was a bad choice of materials, but what has these guys so scared of the stuff?

 

Liability, probably.

Otherwise, I would think you would just get a big estimate from them.

 

What would be the liability of working with aluminum wires (sorry real newbie question)?

 

Short version is aluminum wiring can be the culprit in some fires. I'm guessing the electricians don't want their name on the list of potential suspects if one were to occur.

As an example, you have to use an antioxidant paste when you mate copper and aluminum wires together to prevent corrosion.

Quick Google search would tell you more than you wanted to know about it.

 

A friend in NJ had al wiring and one day he noticed a glow behind the front curtains. Upon inspection the receptacle was glowing red hot. Bad connection and load from other room passing through. I've only worked with it a few times, but it doesn't like to be flexed too often. Pull it out of a box and push it back in too many times and something is going to break.

Look for an older electrician who may have worked with it more often.

Bud

 

It requires special receptacles, special switches, that are rated for aluminum use...Most devices are NOT rated for aluminum use. Check Leviton 12650 rec. and 2651-2 switch as examples.The ones that are are quite expensive compared to copper rated devices. And the old aluminum wiring is not like the "compounds" that are used in modern service entrance aluminum wiring either so much more prone to failure. The bottom line, more expensive to work with, less safe. More risk.

 

Part of the failures can result from being bent or flexed too much and causing breakage. The stuff is finicky to work with and not everyone has experience with it.

 

The real answer to your question, Mike, is there is no safe way to mate Cu directly to Al. Antioxidant paste is a necessary addition when terminating Al conductors, but it does not and cannot prevent galvanic corrosion, which will happen when Al and Cu are placed together.

Switches, receptacles, lugs and circuit breakers that are rated to accept Al are nice to know about and to use, but they can be both more difficult to find and more expensive. In addition, those devices are no help when you want to connect a light fixture with CU wires to the Al house wiring. The bottom line is that while Al conductors may be fine when used alone (Al is still used occasionally for the utility feed in commercial environments, for example), there is no way known to splice them to Cu without creating a fire hazard.

Can the Aluminum wiring in your aunt's new condo be replaced or repaired to effectively and permanently reduce the possibility of fire and injury due to failing (overheating) wire connections and splices? Yes. Can you do the work? Yes, if you're careful and thorough.

One option is to rewire the entire system with modern wire. If it is wired in conduit, that might be an option for you. If, OTOH, it is wired with cable, that becomes an expensive and invasive process best left to professionals. Another option is to add a short piece of Cu conductor to each Al conductor in each box. The trick, of course, is doing that without allowing the Al wire to actually touch the Cu wire.

COPALUM Splices are one way to do that, but they may only be available by contracting with a licensed installer. AlumiConn connectors are another approved method, and are totally accessible to DIYers. In fact, you can get a free sample of those to give them a try.

Some other things to keep in mind:

• Do not, under any circumstances, believe that there is a safe way to splice Al to Cu using a twist-on connector. There isn't. See What’s Wrong With Using Twist On Connectors For Aluminum Wire Repairs?
• Aluminum is not as good a conductor as Copper. For that reason, a circuit wired with 12 AWG Al is equivalent to one wired with 14 AWG Cu. It can have 14 AWG Cu extensions added to it, and it should be protected at no more than 15 amps. A 20A circuit should have 10 AWG Al conductors and 12 AWG Cu conductors.
• When you have done everything needed to eliminate the risk in your aunt's condo, remember that her safety, long-term, also relies on having this same work performed by her immediate next-door neighbors.

 

The reason they are scarey is that the problems are unpredictable and inevitable in the long term.

Dick

 

Another issue is trying to fit the connectors into the boxes. Lets just say it is not fun.

 

Aluminum and copper wiring should NEVER be in direct contact! Even using aluminum rated switch and receptacle devices rated for aluminum wiring (CO/ALR rated) doesn't completely remove the risk if the exposed wiring attaching to the devices isn't properly abraded and coated with antioxidant before they are attached. Here is some reading material for you, Mike.

http://www.cpsc.gov/cpscpub/pubs/516.pdf

Some insurance companies won't even insure a home with aluminum wiring. You should be sure your aunt's insurance is totally up to snuff with full replacement value coverage. That takes care of the structure and contents, but doesn't cover injury or loss of life due to fire caused by aluminum wiring.

I have literally reams of material on aluminum wiring I got from Dr. Jesse Aronstein if you are interested, more than I could ever post on here.

 

Mike, did she buy the condo or is she renting? She may have legal grounds to break the lease or rescind the sale if she bought it without knowledge of the aluminum wiring.

 

The purple connectors from Ideal allow the use of CU and AL in contact with each other.

 

That's true, good point. And, they are even U.L. Listed, but they also have an abnormally high failure rate and are not approved by the Consumer Product Safety Commission. Jesse Aronstein has a paper on this. The short version (from my memory) is, there was a meeting with U.L., VP of Engineering from Ideal, CPSC and Wright-Malta testing labs (Jesse Aronstein). When questioned about the failure rate of the Ideal 65 twister connector, the VP from Ideal stated that the Ideal 65 twister (purple wirenut) was intended for low amperage connections of copper to aluminum wiring in applications such as light fixture installation although the Ideal literature did not state this. At the end of the meeting the VP from Ideal agreed to have the literature amended to state the low amperage intent as was discussed in the meeting. Later, the Ideal literature was never changed.

Interesting note: The Ideal 65 twister wire nut is U.L. Listed for copper to aluminum connections, but it is not U.L. Listed for aluminum to aluminum connections. Why is that?

 

The splices in the photo in this article were covered with the purple connectors from Ideal: ALUMINUM WIRING REPAIR. Still want to trust them?

Additional evidence that the U.L. is not mistake-proof, IMNSHO. In fact, I don't know why Ideal and the U.L. haven't been sued for this.

Bottom line?

 

Thanks for the info guys.
Some how I've managed to avoid alluminum wiring in both my older homes (previous 1950's and current 1930's), so I have not had any experience with this stuff.

 

Aluminum wiring was used in residential applications in the 1960's and 1970's.

 

.


Too much emphasis was put on galvanic corrosion in the past which led people to believe that a little anti-oxidant would suffice. The real issue is that copper and aluminum simply expand and contract at vastly different rates which causes the connection to loosen. That is why the COPALUM crimp connector works.....as it is a virtual weld that does not allow any physical movement between the two wires.

My buddy and I (he's the Master Electrician) converted my old house a few years back. We pig-tailed every receptacle and switch and every light fixture with COPALUM connectors as requested by my insurance co.

Once it was done.....I slept a lot better from that point on.


.

 

But was first U.L. Listed for residential home wiring in 1946 although I have never seen aluminum wiring in a house built during that time frame. Maybe they all burned down.

BTW, U.L. was strongarmed by the Fed Govt to approve residential aluminum wiring in 1946 because of the continued shortage of copper and the need for plentiful housing stock for returning GIs.

 

Although expansion at different rates was certainly an issue, corrosion was a much larger issue. Aluminum wire starts to oxidize as soon as the insulation is stripped off and it comes in contact with the air. Oxidation creates resistance and resistance produces heat.

 

.


I guess in the end everyone agrees about the dangerous characteristics.

Though there are varying opinions.....as one source says this.....


C&P

Aluminum oxidation

Most metals (with a few exceptions, such as gold) oxidize freely when exposed to air. Aluminum oxide is not an electrical conductor, but rather an electrical insulator. Consequently, the flow of electrons through the oxide layer can be greatly impeded. However, since the oxide layer is only a few nanometers thick, the added resistance is not noticeable under most conditions. When aluminum wire is terminated properly, the mechanical connection breaks the thin, brittle layer of oxide to form an excellent electrical connection. Unless this connection is loosened, there is no way for oxygen to penetrate the connection point to form further oxide.

Coefficient of expansion and creep

Aluminum wire used before the mid-1970s has a coefficient of expansion that varies significantly from the metals common in devices, outlets, switches, and screws. Many terminations of aluminum wire installed in the 1960s and 1970s continue to operate with no problems. However, problems can develop in the future and some connections were not made properly when installed, including not wrapping wires around terminal screws and inadequate torque on the connection screws. There can also be problems with connections made with too much torque as it causes damage to the wire.

Aluminum and steel both expand and contract at different rates under thermal load, so a connection can become loose, and loose connections get progressively worse over time. This cycle results in the connection loosening slightly, overheating, and allowing intermetallic steel/aluminum alloying to occur between the conductor and the screw terminal. This results in a high-resistance junction, leading to additional overheating. Although many believe that oxidation was the issue, studies have shown that oxidation was not significant in these cases.


.

 

Although I agree with a lot of what your source says, I don't agree that oxidation is that insignificant. Your source states that expansion at different rates is the more likely culprit for problems with aluminum wiring terminations. The terminations most often discussed as failures were typically made with a wire nut, a twist-on mechanical compression device with a live steel spring intended to keep constant contact pressure on a connection. Even the Ideal purple wire nuts have a similar zinc plated steel spring. There are literally hundreds of documented failures of this type of mechanically secured aluminum to aluminum and aluminum to copper connections with and without antioxidant compound. I just don't see how expansion and contraction at different rates of the two different metals can be relevant when the connection is mechanically compressed by live spring tension.

Who is your source, can you provide a link?

 

San Diego Home Inspector Electrical Inspections

 

What I posted came from the Wikipedia page on the subject.....taken with a grain of salt.....

However.....just in my opinion.....it actually does make sense to me. I agree that corrosion plays a role, but I think it's more of a secondary effect, than an actual cause. Thermal expansion is incredibly powerful.

Any type of mechanical holding device has a certain limit, and if you simply apply a greater force exceeding that limit, then the result is inevitable. The spring tension of a twist connector cannot maintain the intimate bond that is needed to achieve a low resistance connection. The very nature of the spring material allows for movement.....which leads to thermal expansion.....which can then lead to corrosion.....which leads to greater expansion.....which then leads to greater resistance.....and so on and so on.


.

 

And there is a lot of merit to your opinion, in my opinion. That being said, here is something else for you to consider. The thermal expansion at different rates has to do with a copper to aluminum connection in our discussion, but what about an aluminum to aluminum connection such as two aluminum neutral conductors being spliced together at a simple single pole switch? Thermal expansion shouldn't be an issue because both conductors are aluminum, however, there is no simple twist on wire connector approved or U.L. Listed for that connection, not even the Ideal #65 purple wire nuts are approved for that. How were these connections made back in the 60s and 70s? With common wire nuts, that's how. It's my contention that problems that arose from these connections were due to excessive oxidation of the two aluminum conductors.

 

.


I agree.....but even an AL to AL twisted connection is still a joint that may be a source of resistance. And any resistance simply has a bigger effect on AL as compared to copper. The thermal expansion of AL far exceeds copper and therefore the holding power of the connection itself is under higher stress.....even in an AL to AL connection. Remember too that pre 1972 aluminum house wire was a much inferior alloy that needed a greater surface area to carry the same current......and would deform on it's own over time while under load.

I'll throw another question into the mix..... .....if oxidation is the key factor, then why is stranded aluminum wire so much safer? I would think that having a much greater surface area would make it prone to corrosion even more, and yet it has historically proven to be a much more reliable termination.

In the end.....I would guess all the points brought up in this discussion need to be considered.....as they all more than likely play a role at some level.....


.

 

I assume by stranded aluminum wire you are referring to #8 and larger sizes. The only reasons I can think of have to do with #8 and larger sizes being terminated in a lug with the appropriate antioxidant compound rather than with a compression type wire nut with a zinc plated steel spring. The lugs are typically made of aluminum and are dual rated (CU/AL), but the big difference is the aluminum lugs are also tin plated. I have seen a number of connections like this that would also fail, but cannot definitively say whether the failures were due to oxidation or loose connections.

 

The following link has a very good discussion on the issues with older AL wiring. The primary issues seem to be thermal expansion issues between AL and steel, creep rates of older AL wire alloys, and formation of alloys between AL and steel.
http://www.aluminum.org/AM/CM/Conten...usePreview=Yes
Oh, and the number one cause of most failures in the world, poor workmanship.
I think the bottom line is that there are a lot of reasons to be concerned with the 60-70s era AL wire in homes.

 

Good article Thanks Sparky.

 

Thanks for all the info everyone.

A bit of an odd twist to my Aunt's situation....

Apparently the entire condo subdivision is still alluminum wiring (scary).
Provided the electrical is left as originally installed (or repaired by the condo company), any electrical work required is covered in the condo fee costs.
Long story short, they are making it so that no one will want to upgrade from originally installed which is even worse then the fact provided in this thread.

 

That is not a good situation. Apart from having the place rewired at her expense I would replace EVERY receptacle and switch in the home...at least then you can inspect and catch any loose wiring etc. and be sure you have correct devices and good connections. Again, you can get these devices, just not cheap. But at least that is better than not knowing what is there. I once lived in a rental place that had it....Did not know it until a receptacle shorted out. Someone had installed a regular device in there and it was just a matter of time before it worked loose.

 

Jim, here's a scary thought. Up until the early 1970s, regular devices are what were used with aluminum wiring. The AL-CU markings meant nothing, they were still just regular devices.

 

Mike, here is a good piece of reference material by Dr. Jesse Aronstein for your use. Hopefully it will help you help your aunt.

http://www.kinginnovation.com/pdfs/R...Fire070706.pdf