That is a question that may not have a specific answer. Even though, in practice, many tasks are often carried out "Live", as Bennie says, it is usually out of convenience not necessity. How can you tell someone that it is acceptable to risk Injury or worse?
Even using myself as a example, there are times that I will work on an energized system, and times I will not. It is not always for the same reason. Sometimes, I will just not feel comfortable doing it live that day and will request a shut down - even though it may be a task I have performed many times in identical situations. I feel that working live requires a cool head, a steady hand and a degree of concentration. When one of those is out of place, I usually just won't do it. That is what causes accidents.
I would like to see more opinions on this.
