Talking about electricity -This is something I witnessed:
In 2009 I was building a new surgery center. I was the Project Executive/Sr Const. Mgr. for this project and the project had amongst other things a MRI. For those that do not know, a MRI is a Magnetic resonator that creates specific frequency fields that the protons (because our body contains iron) in our body reacts to which then, the computer translates into images.
Anyway, for these to work you need to create a Faraday cage to prevent any radio frequencies interfering with the MRI.
The way they usually go this is to sheet the walls with sheet rock , then plywood, then copper sheeting glued on (usually 30-36 ga). All studs in Hospitals are steel.
Sorry for lead up. So, to make sure the screws nor and other part of the metal substrate framing is touching the copper to make sure there will be no possible RF bleed in.
So........... how do you test for this ??? ..........well with electricity of course ! So this contractor's method was just take a extension cord with a plug on one end and an alligator clip on the hot lead and a alligator clip attached to a screwdriver for the neutral..........of course silly me.
Then they clipped the hot lead to the stud framing and plugged it in and went around the room shorting the neutral lead to the wall, If there was a screw heads that were touching copper it would short and blow a hole through the thin copper. They could then reset the screw head and repair that new hole with copper foil tape.
When I saw the job lights dim and I heard a "crack" I ran over and saw what they were doing. Remember this was job that had several sub contractors on it and this clown just electrified the steel studs?!!. Thank God no one was shocked and there were no Safety people onsite. Anyway nothing surprises me anymore .......... until the next idiot comes up with something even crazier ! .......... but it did do the job.