[Hallicrafters] Alumunum wiring

[David Hallam]

The reason you have to tighten the screws in your breaker panel and the reason that aluminum wiring in houses caused fires was not because aluminum has more resistance and creates heat.  The greater resistance of aluminum is compensated for when it is installed by using 2 AWG larger wires which have the same resistance as the specified copper wire size.  The cause of the fires was due to a property of metals called creep.  Over a period of time when pressure is applied to an aluminum wire the metal will slowly creep away from the point of pressure.  Copper has a very very low propensity to creep.  

Due to the installation methods used in the 60's, creep caused the connections at outlet boxes and switches to become loose creating a high resistance connection and heat.  The heat accelerated creep which increased the resistance creating more heat.  The problem was solved with the installation of a copper pigtail between the end of the aluminum wire and the outlet or switch.  Builders were supposed to retrofit houses with these pigtails.

----------------------------------------

From: "Roger (K8RI)" <Hallicraftersgroup at rogerhalstead.com>
Sent: Monday, September 10, 2007 2:46 AM
To: "Bob Young" <youngbob53 at msn.com>, <hallicrafters at mailman.qth.net>
Subject: Re: [Hallicrafters] Alumunum wiring 

According to the instructions, I'm supposed to retighten/torque the large 
allen screws that hold the 4 ought aluminum, in my main breaker panel once a 
year.

Roger (K8RI)

>
> The reason Aluminum started so many fires is that it is not as good of a 
> conductor as copper and has more resistance so it creates more heat. It 
> used to expand and contract a lot with use and gradually loosen up the 
> screw terminals in the outlets and other places creating a bad contact. 
> This bad contact used to heat up and some of them started fires.
> Oh and yes I love the glow of tubes.
>
> Bob KB1OKL
>>
>> >
>> > Regarding the price of copper...
>> >
>> > In the wind power industry (and probably elsewhere as
>> > well) I have seen a shift toward aluminum cables
>> > instead of copper cables...I've also seen transformers
>> > wound with aluminum rather than copper. Wonder how
>> > long before aluminum wire becomes the standard?
>> >
>> > WB6FQL
>>
>>Never unless you want to relive the late 60's when it was used in many
>>homes; usually cheap tract style. Created a bit of a ruckus with fire
>>departments. Banned by NEC shortly after that.
>>
>>Carl
>>KM1H
>>
>>
>>
>> >
>>
>>
>>
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