Mike Harrison wrote:

On Sat, 16 Oct 2004 13:52:13 +0100, Stefek Zaba wrote:


Mike Harrison wrote:


This is normal for any non-earthed mains operated device with a metal case

aye, more or less;


- it's capacitive coupling of the mains through the transformer

pickyif it's through the transformer it's scarcely capacitive, is
it/picky


Yes - transformers have capacitance between their primary and secondary windings.



neither of which is normally connected to the case.

Unless the case is earthed it is EXTREMELY bad practice to even use an
RFI filter connected to the case.

However it is done, and the net result is a case at 110vAC with respect
to neutral. albeit at fairly low potential.

I suspect they assume it will be connected to some other properly
grounded kit.