• For grounded or non-grounded live networks in land, marine and sub-sea installations

• 3 Individual channels, True r.m.s. measurement

• Non-resistive earth current offset function

• Restricted or Unrestricted earth fault detection

• Highest up meter reading, Pathfinder function identifies channel trip

• Analogue output proportional to highest earth current level (F-version)

• Optional Slave Indicator

Application

The three channel digitally controlled KCM363x monitors up to three earth current channels in a non-grounded (IT) or grounded TN network and its protective earth. Unit can be used for either Restricted or Unrestricted earth fault detection. There is individual relay for alarm or trip of load breaker.

The unit reads the level of earth leakage directly in mA. The standard range is 0-150mA. Larger scale values are available, typically 500mA, 1A, 2A, 5A and 10A. The 3-channel KCM363x automatically locks the meter to read the highest of the three channels.

An AC or DC auxiliary voltage is required for the unit. Start of monitoring function is inhibited when auxiliary power is switched on (default 2secs delay). In this way false tripping during power up.

The meter status LEDs give at a glance the clear safety message:

• ALARM
• HEALTHY

General
RCD MEASURING PRINCIPLE
Earth current is measured by a IG-transformers CBCT (Core Balance Current Transformer). The measuring technique is based on the principle that the sum of the phase currents in a fault free circuit is zero. If an earth fault present, the sum of the phase currents is not zero. This current differential produces a signal from the IG transformer, which is proportional to the earth current. All loaded wires shall go through the CBCT.

OUTPUTS
The unit has C/O relay outputs for  Alarm/trip. All relays are fail to safety configured. A trip LED flashes when the trip level is passed, the relay trips when the delay has elapsed. The timer resets if the fault is removed during countdown. Offset, trip levels and delay are settable on unit front. The trip delay is common for all 3 channels.

The isolated analogue output proportional to highest up channel. If output is used for remote meter reading, we recommend 0-1mA for the slave indicator.

OFFSET FUNCTION 
Only the resistive (ohmic) earth leakage current is a measure for the insulation condition between the AC supply and its protective earth. Any reading of leakage current in a fault free network will be caused by the networks spread capacitance. An offset potentiometer on the rear allows normal reactive (capacitive) currents to be ignored.

“PATHFINDER” FUNCTION
The flashing pattern of the Warning or Alarm LED on the KCM363x identifies the channel producing the trip.