"40 Ax" designation indicates the maximum rated current of the circuit breaker, which is 40 amperes. The "Ax" might refer to a specific series or model within ABB's product range.
"2 Pole" designation signifies that the ELCB has two poles. In electrical terminology, a pole refers to a set of contacts that opens or closes the circuit.
"100 mA" indicates the sensitivity of the ELCB, measured in milliamperes.
primary function of the ELCB is to protect against electrical shock by detecting stray currents that flow from the live conductors to the ground (earth).
ABB FH202-402100 likely features a mechanical tripping mechanism that activates when the leakage current exceeds the predetermined threshold.