[dhdc]

A faraday cage does not require grounding to work, but its still recommanded to properly ground microwaves.

Also, unless your electrician had a catastrophic fuck up, the metal cage will never be at live voltage, with or without grounding.

[ganzuul]

The specific scenario I have in mind is a student living on their own for the first time, cooking with a microwave in their room. Many catastrophic fuckups that we were quick to forget took place during this phase in life.

You might take apart a microwave oven and discover that there are actually several pieces of sheet metal in them. Expensive ones connect them by staked wires. The capacitor is usually rated for 2000 volts and it packs quite a punch.

[dhdc]

How does a student living on their own has to do with anything about microwaves having "lethal potentials"? And what does the high-voltage capacitor has to do with sheet metals?

I'm sorry, but I really cannot follow your logic here.

[ganzuul]

Have you ever looked inside a very dirty computer? It's quite simple.