The MUYA GT5206A is a digital RCD (residual current device) / ELCB tester that verifies earth-leakage circuit breakers trip correctly and within the required time when a fault current is simulated. It supports multiple test currents (typically in the 10mA-1000mA range) and both auto and manual trip modes, giving electricians a pass/fail readout on trip time and trip current. This is a compliance-testing tool used to confirm that a building's earth-leakage protection will actually respond in a real fault.