Current monitors have many advantages over voltage monitors because they provide protection against both supply line and load side faults.  They protect against single-phasing and current unbalance problems that can be caused by voltage supply problems, bad contactors, loose wiring, bad wires or damaged motors.  They also provide very reliable overalod and underload protection.

Current monitors are used to detect heater element failure, loss of load, peak power loads, runway and radio tower light failure, feed rate, dull bits and blades, conveyor load jams, current demand level and to keep tooling loads at their most efficient point.