Matty F wrote:

That's a good idea. in my case there is only one electrician, so I
think he should have his own special lock. If I'm helping him I'd be
inclined to short the live wire to earth and have some kind of
indicator near where we are working to show if the wiring becomes
live. That may not be easy with 600v DC when there's no earth for 6
metres.

If there's you and an electrician that's two padlocks. This is basic
electrical safety stuff. Have a browse around the Reece website. There
are useful ideas and info on there. If you have CO2 floods or other fire
fighting equipment it's also worth considering a sign in/out or tag
system.