I am looking for advice please, the down stairs lights went out last evening so I went to reset the RCB and it wont reset. Blue flashes from the rcb. I have removed all the down stair bulbs and turned all the light switches to off but still I can't reset the rcb. This is the first time in the 15 years I have lived in this house that lights rcb has tripped. I have had to reset the ring main rcb a few times in the past through my own fault. The house was new when I moved in. As all the bulbs are removed and the switches off could it be a florescent unit fault? Any advice would be appriciated.