No idea here, I've had sp in this house since the70s and no problems with
isolation. I suppose one might say its proof against idiots, but then
someone always comes up with a better idiot.
Brian

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From the Sofa of Brian Gaff Reply address is active
"Kevin" wrote in message
...
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?

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Kevin