[In Ontario, Canada]
I have a "furnace room" (it's a room that contains my furnace, and also washer / dryer, water softener and water heater). Recently I had the furnace replaced and the contractor used the armoured/metallic BX cable for wiring the switch for it:
Exposed NM cable doesn't seem right, but it's at ceiling height (~8 ft), safe from flooding and out of the way, and it's been like that for as long as I can remember, without much issue.
Should that exposed NM cable be replaced with BX cable? I'm assuming it's not code, as the furnace contractors probably wouldn't have spent the extra time and money using BX for the furnace switch if it were. Searching online I didn't find anything conclusive about it.