In the past, it was necessary to use an auxiliary power supply and a current transformer. The DIA53 is packaged in a DIN rail-mount housing, 17.5 mm wide with a 12 mm through-hole. It is self-powered and capable of monitoring up to 100A ac with an isolated transistor output. Current monitoring ranges are available for: 2-20A, 5-50A and 10-100A ac. To minimize inventory, it can be wired for NPN or PNP switching. A red LED visually indicates an alarm condition.