My daughter recently moved house. She has been plugging her toaster into a RCD socket next to her hob - it worked well for a few weeks. Now the RCD socket is clicking continuously and won't stop. She has unplugged the toaster so nothing is plugged into it. If she plugs something in to it, it won't work and the clicking continues. She tried turniing the power off and on but it made no difference. The noise is driving her batty, it's a bit like an alarm going off - what could be the problem?