John Towill wrote:

A word of warning, if you are using an electrical appliance on a long lead
plug the RCD into the end of the extension lead. If there is a long lead
between you and the LCD the finite time taken for it to react could give you
little or no protection.

What a load of rubbish!

The RCD will trip just as quickly whichever end of the lead it is at
(within a few nanoseconds anyway, immaterial to your safety).

What this posting *may* be referring to is the CPC (earth) conductor
resistance which *does* affect the speed at which an MCB (overload
protection device) will trip. However you'll never have an MCB at the
'user' end of the cable, it's not practical. The point of using an
RCD in this situation is that it overcomes the possible problem with
the slowness of the MCB (and offers other protection as well).

--
Chris Green )