I remember having seen microwave ovens without the earth connection.
My first question is : Is it correct that if you touch the MOT transformer chassis, but leave the other terminal floating in air without touching anything, you won't get a shock? Since there is no path for the current to flow back to the other terminal.
My understanding is, before touching the secondary winding, the whole secondary is floating, so the whole secondary winding is like a capacitor in air. Now when you touch one terminal of it, the current in the whole secondary winding has no other source, so only a tiny amount of charge flows through you body to bring the terminal you touch on the secondary to ground voltage, 0V. So, in conclusion, it's safe to touch a floating HV transformer as long as the other terminal is well insulated.
But that doesn't seem right...
Edit: In reality though, perhaps the secondary winding is not totally insulated from the core, so part of the HV in the second winding can arc to the core then arc to the mains, which flows through the ground and complete the circuit, which gives a shock?
My second question is : Suppose for safety reasons I grounded one terminal of the MOT transformer. How do I check if the ground wire really works (i.e. it is really connected to the metal plumbing below where I stand?) My friends says to connect the chassis to a water puddle on the floor through a resistor and use the multimeter to measure the voltage between the resistor. Is that the usual way it's done?
Edit: I want to construct a sputtering chamber, the chassis should be grounded, while inside the chamber there will be a high voltage electrode. Using a flyback transformer or a MOT, the high voltage can be generated, but I'm still not comfortable connecting one terminal to the chassis.