How to Calculate Full Load Amperage
Certain appliances, such as refrigerators and air conditioners, require the calculation of what is known as full load amperage. One calculation is for the amperage use during their low-power phase, such as when the refrigerator is only running its fan, and another calculation for amperage use when mechanical implements are initialized, such as when the compressor turns on to begin the refrigeration cycle. The second calculation is larger than the first by a significant amount and signifies the full load amperage. This is important to know when installing an appliance on a circuit.
Locate the electrical information label on the appliance. This is a metal stamp permanently affixed to the body of the appliance. In some instances the information is embossed directly onto the surface of the appliance. This label contains all electrical information for the appliance.
Locate the wattage usage information. If there is more than one number use the largest.
Ascertain the voltage requirements of the appliance. This information is also available on the electrical information stamp.
Divide the wattage by the voltage. Amperage times voltage equals the wattage of the appliance. Thus, wattage divided by voltage calculates the amperage requirements.