ELR & CBCT

ELR Earth Leakage Relays along with CBCT are used to detect
leakage current in the earhing. If the earthing is not
proper a small amount of current will appear (in the order
of mA). ELR will continuously monitor the leakage current
if it exceeds the set threshold an output electromechanical
relay (which is inside the ELR) will operate. The output
relay contact can be connected to circuit breakers /
contactor to isolate power supply or alarms.

CBCT Core Balance Current Transformers these will come in
different sizes. the core material will be either nickel or
alloy of nickel, copper wire will be wounded on the core
and properly insulated. The 3-phase line along with neutral
are passed in this core and secondary is connected to ELR.
Idealy the leakage current should be zero if any earth
leakage happen the leakage current will appear at CBCT
secondary it will be detected by ELR.