Some may require "hard wiring" by virtue of the thermal limitations of
a BS1363(/A) plug.

- It is not good practice to wire a 3kW immersion off a 13A plug,
since it can draw 3kW for prolonged periods (hours).
- It is reasonable to wire a 3kW oven off a 13A plug, because it will
only draw 3kW for short periods unless the door is left open.

I'm not convinced the heating effect is down to pin contact area, I
think a significant amount is the thermal dissipation of fuse holder-
tabs & fuse (combined 8W or so) which heats both flex & fixed wiring.
Hence using a fused-spur for "hard wiring" does not gain you much
either. I found my JL tumble dryer plug was blazing, changed it to an
MK 1363/A and it now runs almost cool.


Alternatively the requirement for "hard wiring" when 3kW may as much
be to prevent it being plugged into a 2G socket (shared with say a
tumble-dryer) or into a multi-way adapter (which should be fused but
might not be if very old).

You can get larger MK Sentry-1 boards (12-way) incidentally - they are
on Ebay currently about £24. Note that Sentry-1 & Sentry-2 are
incompatible, Sentry-1 seemed tougher than the flimsy later offerings.
Getting spare Sentry-1 parts is difficult. To identify Sentry-1 the
CPD cover is translucent smoked grey, Sentry-2 is a solid cream colour.