Hello there and welcome to Just Answer. My name is XXXXX XXXXX I will be assisting you today. I am an engineer with over 30 years of electrical and electronic training, repair and installation experience. I will try and answer your question accurately and precisely so that we can get you on your way.
An ELCB is designed to interrupt power to the circuit in a very short period of time. It does this by comparing the current flow in the live and neutral conductors. In any circuit, the current on the live and nuetral are always equal and identical. When any kind of fault occurs on the circuit, such as a current flow to ground for example, the current will be more in the line conductor than the neutral conductor. The breaker detects this and trips.
Typically, an ELCB will trip in 1/40th second or less so to answer your question, if you were to stick something into a receptacle, you would probably experience a shock for that 1/40th second. On 120V and 240V receptacle circuits, it is my opinion that that level of voltage for that period of time would be harmless although I would strongly suggest that you do not try this.
This level of protection is required for in most household consumer panels outside of the US. In the US it is only required in bathrooms, outside areas and hot tubs and pools etc.
Please let me know if you need further info.