What distinguishes ELCB from Earth Fault Relay?

[yushar]

Hi all,

what is different between ELCB and Earth Fault Relay?
why there is a need to change from eLCB to Earth Fault Relay?

thanks

 

[dlgoff]

The ELCB or http://en.wikipedia.org/wiki/Residual-current_device" trips when there's is an unbalance between the energized conductor and the return which protects the user whereas an EarthFault Relay will trip when there's a fault on the energized conductor which protects the equipment.