Either would work I would think (3cond with ground not connected at the device, or 2 cond). Take a look at the Volex cords (17604 I believe is the one most often recommended). The recommended Volex used to use Belden 19364, which is the cable used for the Bob Crump Asylum power cord, etc., and is a good choice, although it is 14ga 3x conductor, shielded. Definitely do not connect it at the device end. I use some of this on a CD player, first hardwired, now IEC, that was 2 conductor. Works fine.