I would appreciate help understanding the difference between an RCCB and MCB in the context of the situation I'm sharing below.
I have a mini fountain pump in my pond which doesn't have any earth pin (i.e. it has only 2 pins) and it connects directly to the electrical socket. Let's say the submerged portion of the electrical wiring somehow gets cut and exposes the copper wires to the water. An RCCB would immediately cut off the electricity. But an MCB would perhaps take a few seconds to kick in (or would it not kick in at all, given that the pump consumes low current/power?). Is my understanding correct?
Based on the past hour of reading articles and watching videos, I understand that RCCB's work by monitoring outgoing current vs incoming current. When there is a difference (domestic ones seem to kick in at 100mA), the RCCB shuts off the circuit.
But then, wouldn't an MCB do this too? Going through some data sheets, it looks like an MCB needs a much higher current, i.e. 3x the house load. So is the difference that an RCCB kicks in at a very low current (100mA) vs 18 Amps for an MCB?
and what about the reaction time - how long should the current flow for each device to kick in?
I'm in a rural place so don't really have alternates than the 2 pin (ground wire missing) mini fountain pumps. I plan to put about 3 of them into my pond. The house electrical panel already has an RCCB. Is there any reason to install one more RCCB at the electrical outlet next to the pond that's powering these pumps?