Wire Size

Take a look at our ampacity chart to discover the relationship between wire size and amp ratings.

Jackson Location

425 E. Washington Ave | Jackson, MI 49203
(800) 686-9301 | (517) 782-9301

Adrian Location

1153 W. Beecher Street | Adrian, MI 49221
(800) 589-9301 | (517) 263-5500

Wire Size

Ampacity Charts

  • Amperage is a measure of the electrical current flowing through a circuit. Current is measured in amperes or "amps". You must use the correct size wire for the amperage requirement of the circuit to prevent the wire from over heating.
  • The number and type of electrical devices connected to a circuit determine the amperage requirement of the circuit. Usually, a general purpose house circuit is designed for 20 amps. Lighting circuits may be designed for only 15 amps.
  • To calculate the amperage for a circuit, first add up the wattage of all the electrical devices that will be on the circuit. Then, divide the total wattage by the voltage of the system, 110 or 220, and that will give you the expected current or amps.

Wire Size and Amp Ratings


Installation of electrical wire can be hazardous, if done improperly, and can result in personal injury or property damage. For safe wiring practices, consult the National Electrical Code® and your local building inspector.