[sdiy] Grounding of inputs/outputs for modules

Dave Brown davebr at earthlink.net
Sat Aug 4 17:14:13 CEST 2012

Zinsco circuit breakers are infamous for their aluminum/copper construction
and fusing closed so they won't trip.

I just had the panel changed from my Dad's house.  I asked to keep the panel
and went through it but we were one of the lucky ones that had mostly

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of KA4HJH
Sent: Friday, August 03, 2012 6:01 PM
To: sdiy
Subject: Re: [sdiy] Grounding of inputs/outputs for modules

On Aug 3, 2012, at 8:19 PM, Chris Muir wrote:

> On Aug 3, 2012, at 5:03 PM, David G Dixon wrote:
>> In any case, much house wiring used to be made of aluminum.  Our 
>> first house in BC, built in 1951, had all aluminum wiring.  It was 
>> upgraded because the aluminum was considered a fire hazard (it 
>> probably wasn't), but this worked well for 30+ years in those houses.  
>> It neither corroded nor lost conductivity.> 
> What a geeky electrician told me is that the problem is one is dissimilar
metals. The aluminum to copper junction oxidizes over time, and the
resistance goes up, causing more heat to be generated at that junction.

That plus the difference in thermal coefficients. See this article:


I remember when this became a big scandal in the US. I suspect that some of
it could be blamed on improper installation. Used *properly* aluminum should
work just fine.

On a related note, the house next door to us was vacant for over a year.
When the bank finally put it up for sale they discovered that someone has
ripped out all the copper. Fifty feet away and we never heard a sound.

Terry Bowman, KA4HJH
"The Mac Doctor"

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