atg airports are pleased to announce the latest upgrade to be made available for the Micro 100 CCR. The earth fault monitor module, which is offered as an optional extra, is designed to be in full compliance with the requirements stipulated in IEC61822 section 5.7.1.

The monitor is designed to measure the earth leakage resistance of an AGL primary series loop circuit within the range of 10kΩ to 50MΩ. Two thresholds are preset which trigger alarms if exceeded. The thresholds can be adjusted by the user if required and the second stage can be programmed to switch off the CCR in the case of low resistance to earth.

The earth leakage resistance measurement can be displayed directly on the CCR front panel, as well as being made available for remote monitoring via the optional Profibus or Jbus serial communication modules.


The earth fault monitor is installed within the Micro 100 CCR cubicle. The unit contains a high-voltage generator capable of delivering a 1,000VDC test voltage that is applied to the AGL primary series loop circuit.

Whenever the CCR output is energised, the module continuously applies a fixed 500VDC test voltage onto the output series circuit, relative to earth potential. This allows continual monitoring of the resistance to earth during normal operation of the regulator. The measured resistance value is made available to the user.

During the CCR standby mode, the earth resistance measurement may be performed on demand at the higher voltage of 1,000VDC.