How does a 3 phase GFCI work?
Correspondingly, how much current does it take to trip a GFCI?
The GFCI will “sense” the difference in the amount of electricity flowing into the circuit to that flowing out, even in amounts of current as small as 4 or 5 milliamps. The GFCI reacts quickly (less than one-tenth of a second) to trip or shut off the circuit.
Also to know, how does a 2 pole GFCI breaker work without a neutral?
The neutral pigtail is not for the operation of the breaker as the GFCI circuit does not need a referance to ground. if there was 120 volts being used then yes as the neutral would have to be connected to provide a monitored neutral return path.
RCD with additional overcurrent protection circuitry (RCBO or GFCI breaker) In the US, GFCI breakers are more expensive than GFCI outlets. As well as requiring both live and neutral inputs and outputs (or, full 3-phase), many GFCI/RCBO devices require a functional earth (FE) connection.