On Wed, 15 Oct 2008 10:34:11 -0700, Darren New <dne### [at] sanrrcom> wrote:

>
>After a few such tries, one of us got a tingle trying to plug the serial 
>connector into the patch panel. Oh, jeez, house current on the serial 
>port ground. We managed to fry every single serial port, except that the 
>radio shack machine had 2 and we only fried one of them.
>

You're bringing back memories ;)
That reminds me of a job years ago (about 1975). I was using a scope to check
the current flowing through a component and had disconnected the mains earth
wire so that the scope was floating. {So that the probe's reference ground would
not be connected to earth and short out the component's power supply (before
double insulated or floating return paths on scopes. A valve job IIRC)} Every
time someone touched the scope they got a tingle. Looking into it I found that
when the scope's mains filter had been put on back to front and there was a
capacitive bridge between the live-earth-neutral making the chassis sit at 120
Volts. It was limited current but a really sharp tingling. 
-- 

Regards
     Stephen

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