Utilization categories

In electrical engineering utilization categories are defined by IEC standards[1] and indicate the type of electrical load and duty cycle of the loads to ease selection of contactors and relays.

The utilization categories category for low-voltage switchgear defines the characteristic operating conditions for switchgear such as contactors, circuit-breakers, circuit-breaker-fuse units, contactor relays, etc.

The characteristic of the load to be switched or controlled determines the requirements for the switchgear and its correct selection for the intended application.

Contact load in amperes for heaters (AC1) and motors (AC3) can be found directly on the contactor.

Within a utilization category, the suitable size may be selected for the respective type.

Usually utilization category is mentioned in most of the switch gear, with the above contactor stating to be used under AC1 - resistive load & AC3 for motor usage