David WE Roberts explained on 15/01/2011 :
In the UK devices such as
http://www.completeoutdoors.co.uk/Kampa-Mono-Mains-Supply-Unit seem to be
used which sit inside the tent and (as far as I can tell) use a normal
camping extension lead with the blue plug and socket.
Much like the way a caravan or campervan are wired, I think.
So the UK does not mandate an external RCD.

Yes - there has to be a permanently installed RCD located at the socket
outlet at the pole.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk