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Balancing Loads on Switchboards, UPSs, and Other Distribution Equipment

Posted on July 16th, 2014. Last updated on June 14th, 2023.

Problem

You have a three-phase piece of distribution equipment that is not a panel or a meter center. It has multiple single-phase loads on it. All of the loads start on phase A, resulting in an unbalanced panel.

Solution

Using the Circuiting command, you can change the Starting Phase for some of the circuits on the distribution equipment.

This works for:

  • Switchboards
  • Transformers
  • Wireways
  • Bus Gutters / Bus Ducts
  • Enclosed Breakers / Disconnects
  • UPSs
  • Motor Control Centers
  • Generators
  • Transfer Switches

Why? (The Difference Between Panels and Switchboards)

The circuits on panels and meter centers rotate their starting phase automatically. Circuit 1 is on phase A, circuit 3 is on phase B, circuit 5 is on phase C, and so on. If you connect single-phase loads, they end up nicely balanced on the panel.

All other distribution equipment, such as switchboards, do not rotate their starting phases. All circuits start on phase A. If you only use three-phase loads, this works fine and everything ends up balanced. However, when you use single-phase loads, they all end up on phase A. You must move some of the loads to a different phase manually to balance the distribution equipment.

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