Repairing wall warts

Chuck Guzis cclist at sydex.com
Mon Feb 20 12:35:22 CST 2006


On 2/19/2006 at 8:47 PM ard at p850ug1.demon.co.uk wrote:

>Well, if the insulation carbonised and became slightly conductive, it 
>could pass enough leakage current to trip an RCD/RCCB/ELCB/whatever it's 
>called thise week.

Slightly OT:  Back in the 1950's, aluminum/aluminium was introduced as
residential house wiring in the US.  As it had been a proven medium for
long-distance power transmission, the material was viewed as a more
economical alternative to copper.    Along with the new wiring, new
receptacles with a different clamping mechanism were specified.
Unfortunately, many home builders (and inspectors) were completely ignorant
of the second part of the equation, with the result that cheaper
copper-based receptacles were introdced in many thousands of new homes.  

Eventually, the combination formed an ohmic contact of not insignificant
resistance and a rash electrical fires ensued.   Public safety advisories
were issued and many electricians made a nice living retrofitting the
proper fixtures.  One alternative was a copper-to aluminum pigtail that was
attached by means of a special crimping tool, allowing the existing fixture
to be used.

I used to run across the "intended for Al wiring" fixtures at the hardware
store quite often, but I haven't seen one offered for sale in quite a few
years.

Cheers,
Chuck




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