My first question, if you had called me out: What is the age of this unit? Initially this sounds as if the thermostat is not picking up the temperature of the tank and is not "cutting out" as it should do when the proper water temp is reached. The thermostat(s) on a water heater (excuse me here--NOT:HOT water heater) should make good, clean contact with the exterior of the water heater's exterior tank surface. Depending on the age, and environment of the unit's location, if is easily possible that there is some rust or other foreign material between the tank's exterior and the actual thermo-couple of the thermostat. OR: The unit may be old enough that the thermostat is not turning off the heating element when the proper water temp has been reached, then pulls too many amps, causing the breaker to trip.
Aside from the above mentioned benefits, you can also benefit from an electric hot water heater with regards to your energy consumption. Since the heater only eats up a minimal amount of energy, you can be sure that your electricity bill will be lower. For this, you will get to save more money.