Today, I installed a new receptacle in a Vet's office for a TV (mounted high on a wall stand). Cut in a box, and fished to a switch that was conveniently below the TV (and conveniently had a neutral in the box...not a switch loop). The first thing I did was remove the line side from the switch by completely removing the screw (the tricky part), straighten the end with needlenose pliers, and nut the sucker off. The very last thing I did was make the hot splice between the line, the new pigtail to the switch, and the new jumper going to the new receptacle box. Everything in between was the same procedure as working "cold".
The alternative was to spend a very large part of the day figuring out which circuits all the important machines were plugged in to... All without tripping a breaker until it is confirmed that the one you want to turn off won't turn off something very important and expensive, like X-ray developers, 'puters, etc... This was an old farm house converted to a vet's office, with requisite old wiring, and a representation of every type of Romex ever made. I mean, every electrician and their brother must've had thier hand in this place at one time or another. Only God knows what fed what where... (I mean that with sincere heart)...
I don't see the big deal really. I won't work over 150V to ground hot because I've not been trained to do it, but lineman do it everyday with voltages that are 10 to 100 times that. Of course, they are trained.
Only touch one thing at a time...
