Hi, Pete - you have some terms in there we in the U.S. wouldn't quite understand (even though there are those among us who attempt to be cosmpolitan by adding extraneous European vowels, as in "humour"). I don't often talk electricity with 220-volt people. first step is to make sure that everything is properly grounded and shielded - I take it "earthed" is what we refer to as "grounded."
I'm wondering what sort of grounding is used for electronic equipment outside the U.S. We use two-prong plugs that are polarized so they can be inserted in only one direction; or three-prong plugs with a round prong for the ground and flat ones for the other two wires.
I have no idea what you use for microphone cables. Standard guitar mikes in the U.S. use a round, 1/4-inch plug.
this doesn't give you much of an answer, but maybe it will keep the thread alive so you do get an answer. Maybe it will also help me learn a bit about how things are wired outside the U.S. In the meantime, click here for an interesting FAQ that may help you learn a bit about microphones.
-Joe Offer-