How to Determine the Wattage of a Sump Pump

Motor Specification Plate

• The motor specification plate is located on the pump housing, usually near the power input. This plate identifies the manufacturer, operating rpm, voltage and amperage. The date of manufacture, model and serial number are also frequently recorded on this plate.

Required Information

• The two items of information you need to calculate the wattage requirement for the motor are the operating voltage and amperage. Both are listed on the specification plate. The operating voltage is always listed on the specification plate. It is also easily determined by the plug configuration. A pump that plugs into a standard household outlet operates at 110 volts. Heavy-duty pumps requiring 220 volts are identified by the power cord's four-prong plug. These resemble the plug supplying power to an electric range or water heater.

Wattage Calculation

• Determine the pump's wattage requirements by multiplying the voltage and amperage ratings. For a 110 volt pump requiring a 10 amp power supply, the calculation would be: 110 volts x 10 amps = 1100 watts.

Safety Considerations

• Turn off the power source to any pump in service before you inspect the specification plate. Water makes an excellent ground for the current that can escape through any worn or incomplete electrical insulation in the motor's wiring. Using your body as a conductor between a power source and ground will cause severe injury or death.