Originally Posted by CallMeVilla
Look, I don't want to get into a "neener-neener" here about electrical safety. However, my guess is your Master Electrician
has worked on live circuits many times -- as have I. Careful use of a circuit tester confirms the presence of line energy.
But ask yourself: If the light is NOT illuminated and the cicuit tester indicates NO line energy then why do you also have to trip the breaker way out by the garage (or basement) -- unless you are charging by the hour?
On a daily basis, I change out fixtures, receptacles, dimmers, and timers. I am careful to test the lines and WHEN IN DOUBT I trip the breaker. Otherwise, I use my brain.
All that said, for an amateur, it is probably best to trip it. Assuming he can find it!
Because you don't know who wired the house prior to you opening it up. What if there is a hot ground or neutral. Like Britknee said, it could be wired in reverse.
The people on this forum asking questions are NOT professionals. We need to advocate safety. I am not telling you to wear a hard hat and glasses like OSHA requires, but please advocate safety. Telling people who know nothing about electricity to work with hot wires is a liability.
Accidents happen and we're trying to advise people to avoid them.