How to Size an Electric Circuit
To size a circuit means to determine the amount of electricity that a circuit is able to transfer. This is important because if a circuit’s size is too great, it can short out and seriously damage the item plugged into it. Also, if the circuit’s size is too small, it won’t be able to power some of the larger appliances.
Things you need:
- Ammeter
- Voltmeter
- Plug the ammeter into the power circuit. The number displayed on the ammeter is the current.
- Unplug the ammeter
- Plug the voltmeter into the power circuit. The number displayed on the voltmeter is the amount of volts the circuit produces.
- Unplug the voltmeter.
- Multiply the current by the voltage to get the circuit’s size. For example, if the voltage reads 120 volts, which is the average voltage for an American power circuit, and the current reads 10, then the size of the circuit would equal 1200 watts. Sometimes the power needed for an appliance is measured in kilowatts instead of watts. In this case, divide the watts by 1,000. If you take the number from our previous example, then the circuit’s size would be 1.2 kilowatts.
Note: There are some circuit sizing devices that have a built in ammeter and voltmeter. They can sometimes be a little pricey, but if you have one, take the following steps:
- Plug the circuit-sizing device into the circuit.
- Switch the device to read current then write down the number.
- Switch the device to read voltage then write down the number.
- Repeat step five from the previous list.