In uk.d-i-y, Andrew Gabriel wrote:

Is it possible to get a 16A fused spur, or components to make one up?

My new tumble dryer has arrived. It obviously has two heating elements (or
less likely, some complicated power electronics), as it can be configured
for 10A or 16A operation. It is currently plugged into a 13A socket switched
by a 20DP switch on a 32A radial, so must be run at 10A. Drying times would
be considerably reduced using the 16A option, which given the avalanche of
washing it deals with, would be very useful.

You could use a 16A industrial outlet, but this must be protected
at no more than 20A, IIRC. However, it won't meet your criteria of
fitting a standard electrical box.

The BS4343 industrial-style plug and socket is the solution which
springs first to my mind. Some jutting-from-wall is inevitable,
though you can reduce it with a right-angled plug (RS 491-591) and
a small-flange socket (RS 488-983), sinking the enclosure (RS 502-045
or non-flammable box of your own devising) maximally into the wall.
With this range of plugs and sockets there'd be no question of the
contacts being stressed by repeated pulling of the full load.

Neater alternatives, still rated for 16A (though some provide less
complete confidence in contact integrity for long-term use at these
high-for-domestic-appliances loads) include: the IEC "higher current"
style fittings (RS 295-8743 socket, 295-8771) (sometimes seen on
higher-power 19inch rack power distribution units); the ST18 connectors,
used on Aphel mains-distribution units (RS 235-565 plug, 213-4650 socket)
- these don't latch massively strongly - and even the HVAC-style
(heating-ventilation-and-aircon) connectors like the RS 155-9496
flat-to-the-wall socket with mating plug 103-0967. Oh, and there are
the Neutrik Powercon mains connectors: RS 246-8284 for the plug,
246-8313 for the socket; these latter rated at 20A (assuming a 2.5mmsq
flex, they say: not often seen on UK appliances, but a lot more widely
available than hen's teeth or rocking-horse droppings; cut lengths from
a trade counter, often disguised as 'Arctic' cable ;-).

That's the connector side of things - alternatives abound. Now, what
about overcurrent and short-circuit protection? What you'll have with
any of the above - or, indeed, hard-wiring direct into the 20A switch -
is a dedicated socket into which only your timble dryer can connect,
so there's no chance of an overload from multiple appliances sharing
the socket. Is the tumble-drier a load which can itself produce an
overload? I wouldn't have thought so: its motor is a small device not
responsible for most of the consumption, and if the drum gets stuck,
you'll presumably have a slipping belt and possibly internal overload
protection rather than a sustained current of say 40A (a figure chosen
to be high enough to make the appliance cable dangerously hot, but too
low to trip your 32A MCB). And with a short flex, it's unlikely (but
you could do the calcs to be sure!) that the earth loop impedance will
be too high to give you acceptable disconnection times. Without doing
the calculations it's not possible to be certain, but I'm far from
convinced that you need closer overcurrent protection for this
appliance-and-flex (especially if it is, or can readily and safely
be made, a 2.5mmsq flex).

If, however, you're determined to add a 16A or 20A overcurrent
protection element, RS will be happy to sell you either a "simple"
fuseholder for 6x32mm fuses - fuseholder 236-5731 rated to 16A,
pack of 10 16A fuses to fit at 209-9298 or 209-9311 for Aunty Serge;
or a 1-2 module DIN rail enclosure and a 16A MCB (doesn't have to be
physically right next to your plug-n-socket, though you did say you
really don't fancy such a 1-way mini-CU solution); or even a CBE (a
Circuit Breaker For Equipment - different from an MCB in being
rated for much smaller short-circuit currents, but fine used in
conjunction with the MCB you already have on the ring circuit).
For example, there's a thermally-operated 15A CBE as stock number
405-9157, or a 20A cousin at 405-9179, under 6 quid + VAT, or in
pretty rocker-switch style - 286-0719, 16A, or 286-0753 if you
want an Illuminated one. These last are double-pole switching, so
could sensibly replace your existing 20A switch and provide
isolation for maintenance as well as overload protection.

Hope that gives you some useful ideas for your next visit to rswww.com ;-)

Stefek