Electric heat, heat rated insulation on wires, and instead of blk & whi colored wires under the pink sheath they are identified with a red & blk signaling that it's a 220v system.
Yes unless there were some overarching electric code reason why conduit was used in lieu of Romex. if in doubt ask an electrician.
Modern NM/ Romex
THHN is a heat resistant thermoplastic insulated conductor, usually a single conductor. Romex is a brand name for a nonmetallic sheathed cable, it has multiple conductors inside, the insulated ones are insulated with THHN insulation.
Use a # 12 exterior grade or romex
Romex NM. Is the most widely used electrical wire in homes.
Romex, All you have to do is go to a hardware store and tell them you need house wire. It comes in a box. I am not sure how many feet. If you are just looking for the gauge, they will know that too.
It depends on your local building code.
They can as they will support the wire into the box. The deciding factor should be the cost. A BX connector costs about four times the price of a romex connector. Also to keep in mind is that most junction boxes these days have their own built in clamps.
Copper or aluminium.
Assuming 220 volts service 5000/220 = 22.72 Amps. That equates to 10 AWG Romex.
Romex is a manufacturer's wire cable trade name, the 10 refers to the size of the wire inside the cable set. A #10 AWG copper conductor with an insulation factor of 90 degrees C is rated for 30 amps.
A pink venflon is used for blood transfusions and intravenous access. The pink venflon is a 20G which is the size used for some procedures.