GFCI busbar

[PetrosA]

Here's a very basic illustration if it will help. The top panel is your main panel, the bottom is the sub panel. In the main panel, there is one 25A main breaker feeding one 16A RCD and one 16A non RCD. The RCD breaker has four poles, one for each of three phases and a neutral. The regular breaker has three poles for each of the phases. In the sub panel, the top rail is for RCD protected circuits only. The neutral bar on the left comes from the N output of the 16A RCD breaker in the main panel and any neutral from a RCD protected circuit would have to be connected here. The bottom rail is fed from the non-RCD breaker in the main panel and circuits fed from this rail would have to use the neutral bar on the right which is connected directly to the main neutral. If you connected a neutral from a circuit on the bottom rail to the left neutral bus, the RCD would trip.

 

[electrics]

i dont know the other ones but sincerely this forum has glorious friends here, i now see the fact here , as i guess it is reasonable but applications might be different and i just tried to learn punctually ... i thank u u are very kind my dear friends...

 

[LarryFine]

I hadn't read this thread before now, for some reason, so here's my simplification, in plain English (I hope):

Any current supplied through a GFCI device must return through that device. Any current NOT supplied through a GFCI device MUST NOT return through that device.

All of the neutral current must return through the same device that supplies it. You're supplying an entire panel bus as one would supply a single multi-pole circuit.

The same rules apply: all currents, including the neutral, must flow through the same device, so all of the current flows can be compared by the device.

If any current supplied by a different device returns through the GFCI device, it will create the same type of imbalance a real shock or fault will create.

Added: Pete worked hard on that drawing, and it does explain the idea well. Bravo!

 

[electrics]

it is very kind of you my friends , i am proud of having friends like u,u all tried well and i specially thank my friends for drawings too, have a nice day..