Info to backup safety of aluminum wiring?

Page 1 of 3  
I've moved into a house build in 1971 which is wired mainly with aluminum wiring. I've read a handful of published information that states that aluminum wiring (or more correctly, the connections made with aluminum wiring) do in fact create a fire hazard greater than copper wire. I also know that a lot of people state that aluminum wiring does not pose any greater risk than copper if done properly. What I'm interested in is what is "done properly" and have there been tests done on such "proper" wiring methods to prove that they do in fact pose no increased fire hazard?
So in other words, what I'm looking for is published (on paper, internet, etc.) information from reputable sources that would refute the claims made by the information that I've already read making aluminum out to be a fire hazard. A lot of the information I've read so far can be found at www.inspect-ny.com/aluminum.htm
Thanks for the input, Harry
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Make certain you have lots of working smoke detectors while you check out it's safety.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have been installing AL for more than 30 years. There is nothing wrong with the wire. The problems come from the installers and the terminations. If properly terminated there will be no more problems with AL than copper. I do not know of any utilities that use copper any more. All of the long lines and distribution lines in the West are primarily AL. If they were not some maroon would steal them. Which has happened in the old days, 1960-70's. All of that wire was replaced with AL.
Your home and mine (also built in 1971) have lasted this long. Chances are they will last a lot more. This is my 3 home of this vintage. Do you know anyone with a 1000 volt meggar? You will need to unplug EVERYTHING for the test. The meggar can tell you if there is an insulation problem and to a point loose connections.
Most of the published articles are done by fire departments and the copper association. Unfortunately the fire department only gets to visit when there is a problem.
Ideal makes a wire nut for AL-CU connections. About $2 ea at the box stores. Devices should be listed AL-CU and they are harder and harder to find.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I live in the midwest and AL wire is used on most new transmission lines I see. How about homes - I thought AL wiring in homes no longer was approved? When I lived in the south a bunch of "modular homes" factory built with AL wiring burned - had everybody looking at their wires.
Thanks for the info on the meggar.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The problem with AL wiring in homes is at the connections ... transmission lines would obvioulsy have very different connection systems in place compared to your average home. There is for example an approved and tested method of making aluminum wire connections to copper wire using an COPALUM tool. Chances are something similar, but on a bigger scale, is done with transmission lines ... however, comparing transmission lines to home wiring, doesn't really prove much since they are such different systems.
Thanks, Harry
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

What really happened was copper went through the roof in price so people started using AL and AL clad copper wire. Let us not go into the copper clad stuff. During the time that copper was high and the less than craftsmen were using the AL romex there were a lot of problems. One contractor where I lived lost his electrical license because of fires. He even burned his own mothers home down.
The problem lies in the craftsman pulling the wire and doing the terminations. Using the proper devices, ( switches and recpts ) is also a biggie. I know of lots of "electrical workers" that stabbed the AL wire into the back of the devices. Even though the device instructions said not to with AL wire. ( use the side screws ).
Larger AL wire is connected using hydraulic press tools. There are even AL to copper connectors made. I have never seen a hydraulic pressed termination go bad not in 30 years. Providing it was done correctly in the beginning.
Today there is a different alloy used and different insulation. New homes today have circuits above 30 amp AL is still used. ( general guideline ).
You can spend the money for copper. I doubt that you will see a penny when selling the home. No one cares what is in the walls. People accept plastic flexible water pipes ( general term ) all of the time now days. Some new home builders do not even offer to put in copper water pipes.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
SQLit wrote:

Biggest problem was probably the switches and receptacles (although backstabing them would be a real bad idea). After problems developed, UL removed listing on wire and devices in 7-1971. In 9-1971 they started listing devices which are marked CO/ALR. I havn't heard of problems with these devices. If I was using them, I would probably use some anti-oxide paste on the aluminum wire.
Bud--
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Having aluminum in your walls is _still_ a significant house price dampener.
--
Chris Lewis, Una confibula non set est
It\'s not just anyone who gets a Starship Cruiser class named after them.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
It all depends on the real estate market in your area. I know in my area, the wiring won't make much difference with the market we have right now ... even knob and tube wired houses sell. I'm willing to accept the fact that whatever money I spend on the wiring will never be recovered. I want to fix things for safety sake mainly.
Thanks, Harry
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Well I have seen outlets in older manufactured homes which stopped working or would spark inside if you turned on something plugged into the outlet.
Turns out there was aluminum wiring connected to the outlets which had oxidized.
If I had aluminum wiring, I would want to treat it like I do my car battery terminals - inspect each and every connection periodically and clean/apply goop up the connections if necessary.
I would sleep better at night if I replaced it all with copper though...

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thank you for the reply. I like your point about the fact that a lot of the published articles are probably done by fire departments, etc.
But taking the example of the Ideal wire nut ... who do I believe. The information presented here:
www.inspect-ny.com/aluminum/twistcpsc.htm www.inspect-ny.com/aluminum/ideal65.htm www.inspect-ny.com/aluminum/i65debat.htm
Or individuals like yourself and others who've never had issues with these connectors in their own homes? Hence my dilema ...
Also, as a side point ... what do you consider "properly terminated"? Using AL approved outlets and switches, pigtailing, etc.?
Thanks, Harry
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

In addition to using properly labeled fixtures, the main thing you need to use is an antioxidant on the aluminum where it is joined to any other wire or terminal. The AL wire should also be scraped or sanded to remove oxidation before making a connection. (I think this is in the NEC)
The failure mode of AL wiring is a build up of aluminum oxide (equivalent of rust) inside the terminal contacts. This causes a rise in resistance of the junction which will experience heating when current is flowed through it. With enough resistance and current, sufficient heat can build up to ignite nearby sources.
Placing a paste like anti oxidant on freshly stripped and sanded AL wire will prevent the oxidation from occurring in the first place and ensure a low resistance connection.
The terminals on CU/AL rated fixtures are more thermally compatible with the AL so that it does not come loose (due to thermal expansion) which is another cause for increased resistance and eventually heat.
With lamps turned on or something plugged into a receptacle, if you feel any warmth coming from behind the wall plate, you should do something about those immediately.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

of
the
the
about
No offense intended. Sanding a bare new conductor went out 20 years ago along with tape built up stress cones. If there is oxidation on the wire when terminating after you cut back the insulation, testing is in order in my mind. There could be more issues involved.
Anti oxidant is a good thought. The local utility and I have used axle grease in a pinch. I learned that from them not the other way around. All your trying to do is prevent oxidation after the connection is made. I will and do use anti oxidant on terminations and splices.
There were switches and outlets that when the side screws were used no anti ox was needed. I have not tried to buy them in ages cause I do not do that kind of work any more. I do know that going to the box stores and trying to find an device for AL is going to be next to impossible. At least in the box stores I have been in lately.
Pigtailing out in copper is/was an acceptable method. Ask some pros in you local area to see what they do.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
SQLit posted for all of us... I don't top post - see either inline or at bottom.

tape build up stress cones?? What are they? Googled but no results...
--

Tekkie


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tekkie -
An 'old fashion' method of terminating high voltage cabling.
Regards,
Doug

up
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Take the high road, use copper. a roll of copper romex isnt that expensive. skip the hair splitting.
Phil Scott

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
SQLit:
SQLit wrote:
[...]

The AL metal its a superior conductor, and it is durable and easy to work and install.
I understand that oxidation of the Al metal surfaces at the connections are the main problem. AL oxide has a high dielectric strength, meaning that it is poor conductor of electricity. In a simple connection, and over the span of a few years, the AL oxide forms on the exposed surfaces. The AL to AL contact area gets smaller. The electrical resistance at the contact area is increased. Heating is a function of current and resistance. The contact area get hot, and if the resistance is high enough slight melting could occur. the contact area or the cross sectional area of the wires may get smaller, and the resistance, and hence the heating, increases. The connection melts down and fails.
CU oxide does not have as high a dielectric strength, and while the same process can occur the amount of heat produced may be less.
I read that a coating can be applied to the finished connection of AL-AL or AL-CU metals that prevents oxidation over a long period of time. That, I think, is used in marine or shore environments. What is that coating? Crimp type clamped wire connections may provide great enough contact surface area and no access to O2 that the contact keeps a very low resistance that is lower than the wire itself for the life of the connection.
AL wiring is low in cost, and is an efficient conductor. If oxidation is allowed to occur in either AL or CU connections, especially those that are not made with a sufficient surface contact area, and that are not tight, heating and sputtering can occur.
I had a window air conditioning unit that was connected to two 3-wire extension cables. The copper contacts of the power cable had green oxidation, and after the power went on the cable outer ends were warm. Later in the day the cable to cable connection exploded in a flash of light and smoke. The circuit breaker opened. I am highly suspicious of cheap power extension cables that have the wires and metal bits molded into a low melting temperature rubbery plastic cable end with no other wire separators or electrical insulation. Corrosion free connectors may save electricity.
Ralph Hertle
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You made some good points on the differences between Al and Cu. Just to further clarify, Cu has both and electrical and thermal conductivity that is nearly 65% greater than that of Al. Not only does conduct electrons better, Cu ability to dissipate heat is far greater than that of aluminum. Cu does oxide at room temperature, but rather slowly. Further, Cu oxide (CuO) does not form a tough coherent film. On the other hand Al is one of the most powerful reducing agents known to man (check out the thermite reaction http://en.wikipedia.org/wiki/Thermite). Any aluminum surface oxidizes almost immediately and as the oxide layer grows conductivity drops exponentially (this is why aluminum is so difficult to solder). Both metals are prone to work hardening (if bend it repeatedly it gets stiffer and then breaks). On the down size Cu is more expensive and 3 times more dense than Al, but weight matters little in a home. If sized properly to compensate for current load as well the use of dielectric greases, Al is a fine choice. On the other hand if done poorly, the joints could easily heat up as the aluminum oxide grows and potentially cause a fire. Without a doubt aluminum makes an excellent choice for high tension power lines, however, in the home I would prefer copper. This doesnt make aluminum unsafe, its just a preference.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

AL is a poorer conductor. Simple physics. Look it up. That's why it has to be a guage larger than copper for the same ampacity.
It's reasonably durable, but not only is it stiffer (both because it is stiffer than copper to begin with, and because it has to be a gauge larger for the ampacity), it's more brittle. Hence, more difficult to work with than copper for the same ampacity, and more likely to get work-hardened and crack if not handled properly.
And finally, due to its dialectric and "cold creep" properties, under identical conditions, it will deteriorate faster than copper.
As such, aluminum is far more sensitive to sloppy workmanship, codes _require_ anti-oxidant grease (not necessary for copper), and most municipalities have banned the use of aluminum in residential wiring.
Certainly, for power distribution (60A and up), its price advantage is enormous, so you do what you need to to make it safe.
But in general residential wiring, these days its a very bad idea. And illegal in many places.
I've been working with wiring for a very long time. The only connections I've ever seen burn out (aside from ones physically damaged, exposed to water, or due to unbelievably bad workmanship) have been aluminum.
--
Chris Lewis, Una confibula non set est
It\'s not just anyone who gets a Starship Cruiser class named after them.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ralph Hertle wrote:

GOOD conductor? Yes, if properly installed. Durable, etc.? Same answer. But silver and copper are better conductors of electricity.
--
If John McCain gets the 2008 Republican Presidential nomination,
my vote for President will be a write-in for Jiang Zemin.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.