Enter the overload current and the feeder load current into the calculator to determine the overcurrent relay setting.

Over Current Relay Setting Formula

The following equation is used to calculate the Over Current Relay Setting.

RS = OC / FLC *100
  • Where RS is the current relay setting (%)
  • OC is the over current (amps)
  • FLC is the feeder load current (amps)

To calculate the over current relay setting, divide the overcurrent by the feeder load current, then multiply by 100.

What is an Over Current Relay Setting?


An over current relay setting is a ratio of the overcurrent to the load current, expressed as a percentage.

How to Calculate Over Current Relay Setting?

Example Problem:

The following example outlines the steps and information needed to calculate Over Current Relay Setting.

First, determine the overcurrent. In this example, the overcurrent is measured as 200 amps.

Next, determine the feeder load current. For this problem, the feeder load current is 100 amps.

Finally, calculate the over current relay setting using the formula above:

RS = OC / FLC *100

RS = 200 / 100 *100

RS = 200%