On Mon, 04 Jun 2007 06:24:10 -0000, Rob Hamadi
mused:

On Jun 4, 1:03 am, Lurch wrote:
On Mon, 04 Jun 2007 00:29:32 +0100, John Rumm
mused:

TLC will supply if you ask them, although they don't have it in the
online cat for some reason. RS carry the MK6400S as a stock item.

Thanks for the info.

However to echo Lurch's question: Why do you want a RCD at the head end
at all with a TN-S supply?

The usual reason for using a time delayed RCD on the head end is when
you are unable to meet the earth fault disconnection time as a result of
having a high fault loop impedance (typically TT installs). With a TN-S
supply this is unlikely to be the case.

Also I'm wondering if the ring main is RCD protected. If so, all this
discrimination could be subject to random acts of something or other.

I've got a very old CU with no RCD. Replacing it with a new split load
CU is a job for some time in the future, at which time I'd plan on
running the shed off the non-RCD side.

I think I'd drop the RCD from the house end for the shed. It's going
to be redundant come the board change anyway. Also, as Owain has
pointed out, the 16A MCB would be redundant but it's worth having for
the future if it's going to be on its own circuit eventually.
--
Regards,
Stuart.