grounding questions...

[René Schmitz]

At 15:25 10.05.00 +0200, Ingo Debus wrote:
>
>
>Tony Allgood wrote:
>>It must be said that in the UK all metal cases/parts that are
>> touchable by the user have to be directly connected to earth in any
>> mains powered unit.
>
>What about the tip of a phone jack (when the other end of the cable is
>plugged into a mains powered unit)?
>
>;-)

In essence this is connected to ground via the output of the circuit. 
I think there needs only be a conductive path to mains GND, so that no
parts can (e.g. capacitively) charge up to dangerous voltages. I have an
old BW-TV whose earphone output floats against the otherwise live circuit,
but it charges up. (No connection to mains GND anyway...) Sort of scary
that stuff like that is sold.

Bye,
 René


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