Actually both are done separate wires fed into the conduit. You can not strip NM cable and use it in conduit. The wires from inside a NM cable are NOT suitable for this use. You must use proper rated THHN/THWN wires.In case you did NOT read the very helpful article from The Family Handyman I provided, here is the pic for buried plastic pipe wiring ... Note also the more shallow undergrounded wiring is encased in metal conduit .... BUT BOTH are done without the ROMEX sheathing.