Just a bit nof a supplementary to this if I may... I was fitting a new bathroom light yesterday in an internal bathroom without windows so too dark to see clearly where cables ran on visual inspection of the back box. It's also a concrete ceiling, so was really tough to drill. I'd switched off the lighting circuit at the board but on one of my drill holes, there was a bright flash in the drill, a loud pop and the RCD for the sockets tripped.
I reset the sockets RCD, the drill worked fine and, after I'd finished and switched the lighting RCD back on, the light came on fine. I've tried to reassure myself that, as the lighting circuit was switched off, it was maybe the drill over-working rather than me puncturing a cable (why would it short if no power?) but I'm not so sure. Despite the gloom, on closer inspection of the back box, it did look like there might be cable running roughly in the direction of the drill hole.
I'd really appreciate any feedback from someone who knows what they're talking about (rather than my uninformed guesswork!) Thanks
I reset the sockets RCD, the drill worked fine and, after I'd finished and switched the lighting RCD back on, the light came on fine. I've tried to reassure myself that, as the lighting circuit was switched off, it was maybe the drill over-working rather than me puncturing a cable (why would it short if no power?) but I'm not so sure. Despite the gloom, on closer inspection of the back box, it did look like there might be cable running roughly in the direction of the drill hole.
I'd really appreciate any feedback from someone who knows what they're talking about (rather than my uninformed guesswork!) Thanks