DPB52 is a 3-phase multifunction mains monitoring relay. It is operated in the 3P network and detects not only the phase failure and the correct phase sequence but also possible over-voltages and under-voltages. The supply voltage for the monitoring relay is provided via the monitored network. An alarm delay of up to 30 seconds can be set for the over/under-voltage alarms. It features a space-saving design for mounting on DIN rail.