Question: what is the difference between polarized and nonpolarized power cord?
Answer: An appliance with a polarized power cord has a NEMA 1-15P plug with prongs that match the outlet. It will only go in one way. An appliance with a nonpolarized power cord also has a NEMA 1-15P plug, but the prongs are identical, so it can go in either way. A grounded NEMA 1-15P has three prongs.