S Viemeister wrote:


Is it considered acceptable to have both a tumble dryer and a washing
machine using the same double socket?

No need to worry in practice: a woshmosh runs at its peak of 2 or 2.5kW
only while it's actually heating water, typically only for 15 mins or so
at the start of the cycle; while your "normal" tumble dryer is likely
also to have a 2.5kW heater, and will run at less than 100%
on-all-the-time even when doing wet towels on the highest setting. The
peak load will be 5kW, which near as damn it is 20A (5000/240 = 20.8A,
divide my 5kW by 230 if you want to pretend UK mains is 230V to get
21.7A if you want to panic, but you won't convince me a 240V-design
heater will pull its full kW rating running at that slightly lower
voltage ;-). So, even when both appliances' heaters are on, there's only
the 20A flowing through the double socket, and no decent-quality socket
with incoming conductors sensibly tightened will run anything above
slightly warm...

More, and authoritative, detail over at
http://www.iee.org/Publish/WireRegs/Amd1andRC.pdf