OG wrote...
It sounds like you were 'checking' the electrics without knowing whether
the circuit was on or off. So who is the 'clot' ?

Reasonably assumed to be a blown bulb and not obvious which circuits were
controlled by which switches - which were multi-way anyway so not obvious
whether on or off. The only way of assuring that the circuit was off would
be to kill the power to the entire building which would not have been
acceptable and way OTT for simply unscrewing a single lightbulb with
appropriate care! Apart from that the reason for restoring the lighting was
so I could see to safely adjust a faulty channel on a dimmer rack with a hot
chassis - so a possibly live edison fitting was not exactly a great hazard
in comparison!

David