The SELCO Overcurrent Unit E4200 measures the actual peak values of the three phase currents.

Excess of the preset phase current value (0,4-1,2 In) will immediately activate output relay C (non-latching).

Excess of the preset time (5-25 sec.) will activate output relay B (latching).

Relay B is reset by interrupting the supply voltage to the complete unit.

Tripping of e.g. non-essential load can be performed by relay C via external auxiliary relays.