Three-pole Thermal Overload Relays. Three-pole thermal overload relays designed to protect ac circuits against overloads, phase failure, long starting times and prolonged stalling of the motor. Adjustable relay setting dialTest buttonStop buttonManual/auto resetTrip indicatorSealable cover1N/O & 1N/C auxiliary contactsDirect mounting beneath three-pole contactors or independent mounting on DIN railInsulation voltage 600V, Withstand Voltage 6kV