When you are working on circuits, in a set or on the house be sure the power is OFF.
Decades back, when I managed a parts store, we had to install a floor outlet for a display. I crawled under the building and asked the owner "Is the power off?" He said it was. I asked "Are you sure?" "Yes" he said.
So as I turned a brand new pair of wire cutters into a set of "custom made" strippers for
[You must be registered and logged in to see this link.] wire with a huge "BANG!!!!!!!!"
He yelled 'Are you OK?" "Yeah", I said, "But didn't you say you had the power off?" Uh,............
Thus ended my trust of someone else turning the power off, along with the introduction to just what the term "brown pants" exactly meant.
The moral is: Always turn off the power to the building, and don't trust anyone else to do it correctly. They do make lockouts for a reason too! test the circuit with your meter before cutting, especially on house wiring.
You can also get knocked on your tail from a radio or TV too.
Use the 1 hand rule when working on a set. Keep 1 hand in your pocket, and use the other to use the test equipment with.
If you get tired & sleepy, go elsewhere and nap, not on the bench. At least 1 Ham has electrocuted himself falling asleep and getting tangled up in the equipment.