I'm looking into whether an ungrounded metal box provides good/bad EM shielding.
This thread seems like a definite "good", for reasons of the box acting as a faraday cage : How much shielding does an ungrounded metal box provide?
But when a similar question is asked about ungrounded cable shielding, I am finding some "good" and some "bad". Here is a good: Does an ungrounded shielded cable shield at all?, and #3 of one of the answers is bad: Cable type and decreasing EMI/RFI
"If you don't ground the shield, then it is just a great receiving "antenna" for collecting all your noise, interference, EMI, RFI, etc. And then it is a great method of caacitively coupling all this noise right into your signal wire(s). It is almost worse to have an ungrounded shield than to have no shield at all."
So doesn't an ungrounded cable shield also act like a faraday cage? Is it the fact that the cable shield is physically located closer to the wires that you have to start worrying about capacitive effects?
With that logic, would it be safe to say that an ungrounded metal box provides good EM shielding granted that the electronics you are trying to protect are physically located at a sufficient distance away from the walls of the box?