Skip to main content

CM-Exx & CM-Sxx Single-phase Monitoring Relays

CM-Exx and CM-Sxx are the single-phase current and voltage monitoring relays that provide reliable monitoring of voltages and currents by using the TRMS measuring principle.

ABB’s CM range offers a wide selection of powerful, compact devices for the monitoring of currents and voltages in single-phase AC/DC systems. All come in a housing that is just 22.5 mm wide. This product range includes current and voltage monitoring relays for over- and undercurrent protection, over- and undervoltage protection and phase loss monitoring – from 3 mA to 15 A and from 3 V to 600 V. ABB’s CM range gives your electric installation the highest safety and reliability.


  • Safe and reliable voltage and current monitoring
  • Easy Connect Technology push-in terminals
  • Withstands highest vibrations
  • Easy adjustments via front potentiometer


  • Over-/undercurrent monitoring
  • Over-/undervoltage monitoring
  • AC/DC signal measurements
  • True RMS measuring principle
  • Window monitoring (upper and lower threshold at the same time)
  • Easy Connect Technology with push-in terminals
  • Double-chamber cage connection terminals