Here's the answer

April 27, 2020   photos  

Residual current circuit breaker RCCB. The 100mA is the max acceptable difference in current between live conductor and neutral. If the difference is higher the CB will trip. Sensitivity leakage current, when the rated current is exceeded by 100mA the breaker will trip. That's the maximum tolerance current it can withstand after 40 amps. In general, it means a Leakage Current.