power supplies on the powreedge R810

My question is if both power supplies are plugged into seperate power sources at all times. Will I be able to take a reading on the breakers to see the amps on each power supply and will they be the same or close to it, or is only hte primary power supply actually taking the full draw from one power source and the other power supply just active, ready for the transfer over of power is the first power supply fails?