Gone Outdoors

How to Wire a 480V 3-Phase Motor

by G.K. Bayne

Industry wide, the 480 volt 3-phase motor is the most common of all electric motors. Understanding the proper wiring methods can be a challenge if you are not familiar with some basic rules.

Remove the motor’s wire connection cover, being careful not to lose the four screws. Check the motor nameplate for proper voltage and amperage rating. The motor power supply circuit should be properly disconnected before any work is attempted. You should also confirm that the motor supply power has the correct amperage rating so as not to overload the circuit once the motor is placed into service.

Check the motor connector cover for the proper configuration of 480 volt wire connection. Not all motor manufacturers use the same type of windings. It is better to double check than to burn a motor up and release the magic smoke. Strip back all motor leads with the wire strippers. Following the connection diagram, twist together the individual leads with a pair of pliers and apply the plastic wire connectors in clockwise fashion.

Strip the power supply leads and mechanically make the connection to the three power wires of the motor. Be sure to correctly connect the green ground wire to the proper location on the motor case. This is generally identified as the green screw inside of the motor connector housing. Test the rotation of the motor once all connections have been made. If rotation is not right, interchange any two of the power leads. Retest the motor.

Apply a small wrap of black plastic tape around each plastic wire connector. Carefully fold in each connection so it will fit under the connector cover. Be careful so as not to pinch the individual wires. Reinstall the cover screws.

Items you will need
  • Volt ohm Meter
  • Wire pliers
  • Wire strippers
  • Screw drivers, both Philips and slotted
  • Plastic wire nuts
  • Vinyl black plastic tape
  • Safety glasses
  • Understanding of basic electric repairs

Tips

  • Follow all state and local electrical codes when performing any type of electrical work.
  • It is best to use only U.L. listed materials for any job that utilizes electricity.
  • Double check to be sure that all electricity is off before exposing any bare copper wires.