ABB CM-SRS.21S Current monitoring relay 2c/o, B-C=3mA-1A RMS, 220-240VAC 1SVR730841R1400The CM SRS. 21S is a single functional current monitoring relay from the CM single phase monitors range. This monitoring relay operates with a rated control supply voltage of 220 240 V AC and has a 2 c o (SPDT) output with contacts rated at 250 V 4 A. It provides a RMS measuring principle for DC and AC currents with 3 measuring ranges: 3 30 mA, 10 100 mA and 0. 1 1 A and works according to the open circuit principle. The CM SRS. 21S is configurable