Dave Liquorice coughed up some electrons that declared:

On Mon, 24 Nov 2008 15:58:17 -0000, Steve wrote:

Thanks chaps. I'll go for the oval as I've already got some somewhere.

Simple and cheap. But bear in mind what Mr Gabriel said about damp and
untraceable RCD trips. I'd be tempted to put a squodge of silicon in each
end of the oval.


And don't forget that unset silicone sealant is quite conductive, should one
get a bit over liberal with it ;-

Bit of tape round each end might be another solution to keeping wet plaster
out.

Cheers

Tim