I have my washing machine plugged into a B&Q plug-in RCD. This is getting hot (just in the top left corner) even when the machine is switched off. I believe that there is a solenoid in these devices which are constantly working so some warmth is normal. Is that true? Re-wire due soon with integral RCD but I like to be safe for the moment. Unfortunately the plug concerned doesn't have an on/off switch and is hard to reach, so that's why the plug is always live when the RCD is in.