"Matty F" wrote in message
...
Does anyone have any brilliant ideas about how to ensure the main
power switch remains off when someone is working on the wiring?


Something like this
http://www.findtheneedle.co.uk/image...cts/497067.jpg is what you
should put on the padlock. It is 12 inches X 12 inches (300mm X 300mm) and
highly visible, so people can see it without to much problem. If they say
they didn't see it, then sack them for not having proper sight correction
( spectacles or glasses ) in a place of employment.