The CME420 series current relays monitor undercurrent and overcurrent in AC systems as well
as the current between two threshold values. The current are measured as r.m.s. values (AC)
where the measured value is continuously shown on the LC display. The measured AC current
required to trigger the alarm relay is stored. Thanks to the CME’s adjustable delay times and
variable parameters, device settings can customized to suit every application. Current
measurement is possible either directly or indirectly via standard current transformers (x/5 A).

Product Details


  • Undercurrent and overcurrent monitoring in AC systems 0.1…16 A
  • Indirect current monitoring with standard current transformers x/5 A
  • Transformation ratio n allows adaptation to all standard current transformers x/5 A
  • Different monitoring functions selectable < I, > I or < I/> I
  • Start-up delay, response delay, delay on release
  • Adjustable switching hysteresis
  • r.m.s. value measurement (AC)
  • Digital measured value display via multi-functional LC display
  • LEDs: Power On, Alarm 1, Alarm 2
  • Measured value memory for operating value
  • Continuous self monitoring
  • Internal test/reset button
  • Two separate alarm relays (one changeover contact each)
  • N/C or N/O operation and fault memory behaviour selectable
  • Password protection for device setting
  • Sealable transparent cover
  • Two-module enclosure (36 mm)
  • Push-wire terminal (two terminals per connection)
  • RoHS compliant


  • Current consumption of motors, such as pumps, elevators, cranes
  • Monitoring of lighting circuits, heating circuits, charging stations
  • Monitoring of emergency lighting
  • Monitoring of screw conveyors, e.g. in sewage plants
  • Dust removal in wood working
  • 70 % agreement in accordance with EEG 2012 for PV inverters