@bythewell - There are a lot of jobs which have this kind of responsibility. Every person who works on car assembly, for example, or when building an office block, or when organizing a concert.
That's why all those jobs generally have backups and fail safe measures in place to ensure that the people who do them are never the sole responsible party.
I'm sure it's the same with industrial electricians. In fact, probably more so here than with home repair electricians. They most likely work in pairs or groups and certainly have someone check up on the work they are doing all the time.
I understand why you'd feel that way, but I think that electricity just seems so scary, it makes the job sound scary as well.