Buying a house, Aluminum Wiring?

Around here, you are required to disclose any defects or banned use materials such as Ureaformadahyde foam or aluminum wiring and any other major defects. Aluminum wire was in general use about 35/40 yrs ago and quickly fell out of favor because of the overheating/fire problems

The wire itself is not at issue. It's the possible splices into it and the devices at the end of each run. The lamp sockets and wall plugs use brass screws that cause the problems when electrolysis occurs and over time wires become loose under the screws - high resistance = hot spots = fires.

There is a low temp aluminum solder that will join aluminum to copper/brass, enabling you to install copper pigtails at each junction box, outlet box, etc. It's an Alladin product, comes in a small vial (like a pill bottle) all coiled up with a wee tiny bottle of flux. Use sparingly and heat with a propane torch. What works here may not work there (where you are). Check with your electrical guy about possible fixes and the costs.

You got some very good advice in another post. Call up a local electrician and get his best opinion.

Pete

Hello everyone,

I put in an offer on a house last week (one with enough room for all my tools!). One of the conditions was insurance. I have run into a little bit of a problem. My Insurance company wants an electrician to certify in writing that everything is "safe".

Anyone know how I get this done? The offer clock is ticking...

Who has had problems with their insurance agent with regards to aluminum wiring, and how did things work out?

Thanks,

David.

Good advice. Here in Texas they're licensed, which generally makes for a better inspection.

Even then there is often some CYA involved, so you must still have the knowledge to separate the wheat from the chaff. I welcome third party inspections of new homes, but always inform the prospective buyer that there will likely be some items which will be subject to discussion and not ultimately addressed.

Although I never tried I can't imagine an electrician certifying that a home's wiring is 'safe'. They may be able to check that it was installed correctly and pull the outlets & switches to check the connections and make sure proper fixtures are installed. What they can't do is check every connection in the house without tearing into the walls. The Al wire has a high failure rate at connections and stress point (bends).

Read here for more info:

Yep, every outlet, fixture and splice. It's expensive, time consuming and you'll never be sure you got them all. I'd pass on the house.

In you are in the US, that is a load of crap. I know plenty of owners of these houses with that type wiring and insurance is normally priced. My sister owns one.

jeez buddy, no need to shout.

Entire neighborhoods have AL wiring and have no difficulty getting insurance from all the majors.

scott

I have been reading this thread and started wondering if all of this discussion applies to the service feed into the house. My 20 year old house has a 125A service from the street that is aluminum.

Wayne

Aluminium service entrance cable is common and allowed providing that a listed anti-oxidant compound is used the aluminum conductor terminations. (NEC 110.14)

Having been directly involved in the electrical industry during the big bru-ha-ha involving aluminum wiring for residential applications some 30 years ago, I'd probably do one of two things:

Lew

The stranded Al wire doesn't have the same propensity for failure as 'solid conducter' Al, I'm not a physicist so I don't know why. It is still very common to use stranded Al for dryers, ranges and AC units. And most, if not all, of those transmission lines running over your head are Al.

I beLIEve the NEC has no prohibitions against solid conducter Al branch cicuit wiring but some regional and local codes do.

Don't worry about that at all. Service entrance equipment is rated for connection to aluminum wire, and so are the crimp connectors that the linemen use to install the service drop.

It has to do with what is known as "cold flow".

When you make a connection using solid conductor Al, you have a good solid mechanical connection; however, the Al oxidizes which increases electrical resistance.

When current flows thru the wire, the Al wire heats up slightly and the Al wire softens slightly and begins to flow or ooze, thus reducing the amount of clamping force provided by the termination which causes increased electrical resistance.

Increased resistance causes increased "cold flow" which causes increased resistance, etc, etc, ultimately leading to the wire melting, and then a fire.

BTW, the wire usually melts about 2"-4" from the termination, usually up inside the insulation. Don't have a clue why.

There are many variables to the above process, so the amount of time req'd varies greatly.

Infrequently used circuits may not malfunction for many years, perhaps never, but you never know.

Stranded Al cable OTOH, uses special terminations, potted with "sheep dip" to prevent Al oxide from forming, and special crimping tools to insure a good termination.

It is a totally different world, but the increased termination cost is quickly recovered by using lower cost Al vs copper for large cable services.

Same can not be said for small, 30A max, branch circuits found in a home, for example.

Lew

I suspect that large amounts of current which will cause aluminum cable to jump will cause loose connections also. Years ago I was using a set of aluminum cable jumper cables to jump start a car. Every time the other car cranked, the cables would jump and get warm.

You are confusing two different phenomena.

Cold flow refers to the tendency of a material to deform under mechanical stress. Period. This is unrelated to the cyclic expansion and contraction due to temperature changes as electric current is applied and removed. Cold flow will occur in any overtightened connection, even if current is never applied.

Cold flow is a particular problem with aluminum wire because the stress levels required to produce cold flow in aluminum can be readily achieved with hand tools. Proper tightening of lugs with aluminum wire requires the use of a torque wrench calibrated for torques measured in inch-pounds (or, of course, the metric equivalent). Any overtorqued connection will loosen in time as the material flows away from the stress.

Aluminum and copper both expand and contract as they are heated and cooled. Aluminum, however, does so to a much greater extent than copper, and an

I wouldn't walk away, I'd run as fast as I could. There were a few houses wired with aluminum in our area back in the 60's but they soon made it illegal to use the stuff.

I never owned a house wired with aluminum but have had houses that have had aluminum drops from pole to house. My previous home had to have the special aluminum to copper connectors replaced every 3 or 4 years as they would burn out.

We moved several years ago to a 50 yr old house that had the old screw in fuses so we had a new 200 amp panel installed. When the power company came out to install a new heaver aluminum drop they did not use the special aluminum to copper connectors as they had in years past, they used husky u-bolts to connect the aluminum drop to our copper line, said the old connectors were too troublesome. RM~

Where are you from Rob? Around here (northeast), everything is aluminum from the pole to the main breaker. Copper does not start until you run branch circuits.

from the pole to the main breaker. <

Guess I didn't make myself clear. That's the way it is here (Tulsa), they use aluminum drops to the panel but can't go past the panel. They (power co) quit using the special aluminum to copper connectors due to their failure rate. They quit using aluminum inside of houses years ago. Not real sure how long they did allow it but it wasn't for a very long period of time back in the 60's. RM~

Unfortunately, my parent's house, which was built in the mid-60s, has all aluminum internal wiring. The dining room has started to fail in parts, the light switch to the ceiling lights doesn't work anymore, I ran an extension plug for the lights to an independent outlet so my mother can get light but really, the whole house needs to be completely rewired with copper.

I'm just afraid that I'll get tapped for the job if I suggest it. :)