Good, interesting reply. Thanks, i learned something new today.
Fun to do it. There's a lot of maintenance mechanics who don't understand what is called three wire two hot conductor lighting and outlet circuits which is different than residential circuits. You can get killed if you don't know exactally what your doing even changing out a 120 volt outlet. In this case you have to make certain the neutral is not carrying current.
What I find hard to believe is Union Electricans didn't know this even in the UK. Or maybe they did LOL.
This would be the lighting lay out. Every third lighting fixture on the same circuit. If one breaker is cut off you have two more either side of it that work. In power failures only one in three fixtures work. But that is enough for saftety sake.
If the power goes off. In any hospital in the U.S. the generator has 10 seconds to start and transfer over. This is also true with any nursing home. This is so persons on life support are not effected nor in a hospital surgery except a bare minimum time.