[AMPS] Re: Surge voltage, HV connectors.

[Tom Rauch]

Thanks for the explanation Ian.

I can see I had the wrong idea about your British power lines! I was 
assured you could stick one finger in the socket while standing in 
the tub with barely a tingle, because the whole line floated.

I feel better now about my friend's PA that has the Millen connector 
installed wrong, with the male on the flying lead and the HV 
rectifiers and filters  in a plastic milk crate, and the transformer on 
the floor.

At least now I know it won't kill his wife in the house if he makes a 
mistake, assuming all the earth connections are indeed near zero 
ohms.

BTW, he leaves the cover up on his PA, with a fan blowing on the 
tubes. I'll have to warn him about photon arcs!

> However, the real issue is that mains and HV inside the same cable is
> lousy engineering practice! It would be contrary to product safety
> regulations world-wide, which also explains why suitable connectors are
> not available. 
> 
> HV inside a separate coaxial line with a grounded sheath is much safer,
> even if tie-wrapped together with other cables.

I've seen the ungrounded chassis of equipment rise to several kV 
when the PSU faults to the power mains in this country.

Many designs also y use a low ohm resistor from the negative rail 
to the chassis. Not a good way to keep the negative lead at earth 
potential during a fault.


73, Tom W8JI
w8ji@contesting.com

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