Oops - my bad - I meant to write "Alectrician". He's a regular (same handle) at JLC.
HJ - The sarcastic joke of pseudo-joe-tedesco posts is more obvious over there, where Alectrician's a regular & we know who he is....
That's why I wanted to explain - that it was a joke - about how Joe T thinks you should be licensed to change a light bulb, exactly! Also Joe T's tendency to post very terse answers, and use exclamation marks a lot...
...wow, jokes really die once they're explained, huh?
with BX - armored cable - the sheathing is the ground. It should be connected to the metal box with one of these: