ELCB or RCD Testing refers to checking whether the Breaker is functional and working as it should be. ELCB Testing is done by using the Current Injection Method, wherein simulating an appropriate fault condition, a low magnitude fault current is injected to test whether the device trips or not. A functioning ELCB/RCD will trip the circuit during a Current Injection Test. Since the ELCBs and RCDs are important and critical protection devices, it is always in the interest of the end-user to periodically check the health and functioning using this kind of test. Any test buttons built into the ELCB/RCD can only help test the manual functioning of the breaker. Accurate digital readout of disconnection time. Automatic data hold function. Zero-Crossing Circuit permits testing at 0 or 180. Disconnection Phase Polarity is shown on L.C.D. Display.Auto-Off and Off override. Polarity Trip indicator Positive or Negative Phase. Wiring polarity indicator. It has the measure voltage and frequency between Line and Earth before testing.