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How to Calculate the Amps of an Outlet Using a Multimeter

Bob White

An amp (ampere) is a measure of the amount electrical current passing a specific point in the circuit. You cannot directly measure the amp load of an outlet; that would create a zero-load power source and open the electrical breaker, short the circuit and possibly break your multimeter. In North America, most outlets provide a maximum of 15 amps. In modern construction, builders install 20-amp outlets in kitchens to provide additional power to heating devices.

Measuring amp draw requires a device to use the electricity.
  1. Unplug the device from the outlet. Cut the hot wire for the device with wire cutters. This is the wire with the smaller prong on the plug.

  2. Strip 3/8 inches of insulation off the end of both cut wires. Wrap the wire going to the plug around the red probe's tip of the multimeter. Wrap the wire going to the device around the black probe's tip. Wrap the connections in electrical tape so they cannot contact each other.

  3. Set the meter's dial to the current (A) setting. Plug the device into the wall outlet and turn on the device.

  4. Read the amp draw for the specific device on the meter's display.