u need a multimeter to establish exactly whats going on.Disconnect everything and test for voltage across supply and appliance cables-either the timer has gone down or the immersion is being supplied from another circuit-in which case you would get a voltage across the "appliance" cables when...
I have 16th edition, just wondering what else I need to obtain part p? does every install need PAT testing? do I need to go on a PAT testing course as well as having jobs assessed? cheers for advice