True, but surely this would aid in finding a fault?
Brian

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From the Sofa of Brian Gaff Reply address is active
"Caecilius" wrote in message
...
On Sat, 14 Feb 2015 16:38:03 +0000, Kevin
wrote:
I see that many suppliers now offer both SP and DP versions of switched
sockets, with DP up to 50% dearer for a given make.

What governs which version one should use?

I'd prefer DP, as it means the appliance can't trip the RCD when the
switch is off.

With SP, an N to E short in the appliance could still cause a trip
even if the socket is switched off.