This is how the test circuit tests the reliability of rccb. It is designed for three phase line consisting of 4 slots where three phase wires and a neutral wire can be connected.

Proper Rccb Connection Diagram With Mcb In 2020
4 pole rccb connection diagram. Types of pole in rccb residual current circuit breaker. Types of residual current circuit breaker. This video about the rccb working principle rccb wiring connection and residual current circuit breaker installation diagram explanation rcd wiring diagram rccb 2 pole and rccb 4 pole. Rccb has two pole or four pole and sometimes three pole. It is for single phase line consisting of one live and one neutral wire slot in it. In my last published post i shared a diagram about double pole rcd wiring and now in this post we also publish a diagram about rcd breaker but this diagram is about 4 pole rcd which we can use in 3 phase 4 wire system for protection.
Wiring a four poles rcbo or gfci circuit breaker three phase rccb wiring the three phase wiring for gfci or rcd rccb or rcbo wiring diagram shows the three lines l1 l2 and l3 and neutral has been connected as input to the rccb from main board followed by mcb ie. For single phase load two pole rccb is used and for three phase 4 wire loads four pole rccb are preferred. It consists of two ends where the three phases and neutral wire is connected. Three pole rccb cannot be used for three phase loads. It is as displayed in image below. Three pole rccb is preferred only for two phase neutral system.
It is used in cases of a three phase supply connection involving three phase wires and a neutral. Besides this it is similar in construction and operation as 2 pole rccb.