Hi i have read about rcd problems. i have an old consumer unit with plug in fuses, its an annexe supply and only has 2 circuits. a ring main and a light circuit. Its been fine no problems till 2 days ago, the rcd trips, i removed both fuses and checked the wire both fine, i removed all electrical appliances and switched all lights off. switched unit off and reset the rcd, then switched the unit on, then put the light fuse in. i switched on 2 lights fine, went for a third and it tripped. so repeated the process only this time i put the ring main on, switched on a telly and it tripped. repeated and this time plugged a lamp intoa socket on the ring, switched it on and trip. so no one aplliance or light trips it, its as if its overloaded but then why now after 2 years when nothing new has been added? lastly i repeated and switched one light on and left it, after about 20 mins with no other loading on the circuits, it tripped out. Anyone have poss reasons? faulty rcd? or something else. Also the rcd has labels and a electricity board wire tag to prevent tampering, can i replace my self or have to call them out? any help appreciated.