Only seemingly unrelated, many years ago I learned from an electrician who had worked for a long time in Switzerland (which at the time had more advanced safety standards, that were actually followed) that when working on an electrical plants you:
- first switch mains off
- then put a (mechanical) lock on the main switch (so that it cannot be re-armed accidentally by someone else)
- then anyway never touch a naked wire and manage everything as if the wires were live, using only insulated tools …
I.e.: better be safe than sorry …