Not your typical loads that require GFCI from the NEC, but not impossible to protect with GFCI either, though you may need a stand alone device instead of a circuit breaker that incorporates the protection.I hae three types of loads (hotplate,boiler,socket) all of them is three phase with neutral, system voltage is 400
Three poles, with a fourth paid of terminals or pigtail and terminal and pigtail for the neutral to pass through.just to confirm
Three or four pole is required in star connection?
1. RCDs are generally used with European style distributions which do not have the center tapped single phase as in the US. This includes the occasional country with an ungrounded system that requires a contact for both wires of a two wire circuit.i found this from wikipedia
[h=3]Number of poles[/h]RCDs may comprise two poles for use on single phase AC supplies (two current paths), three poles for use on three phase AC supplies (three current paths) or four poles for use on three phase & neutral supplies. Specially designed RCDs can also be used with both AC and DC power distribution systems.
For the mist part US GFCI breakers do not interrupt the neutral, so it would not require a pole.
I am going by word of mouth and the absence of a third pole space to deduce that the neutral is not interrupted at a typical GFCI breaker.Guess I have not checked that out so I am not sure. I can't recall any GFCI receptacles that do not open both lines, and I guess I kind of assumed circuit breaker GFCI's likely did the same. If you have a fault from another circuit returning via GFCI protected neutral, you will trip the device, but if the neutral is not opened you still have fault current - there is both good and bad in that situation I guess depending on the application.
Now you are going to make me go test one - if I remember this when I next see one. I may get that chance today, will try to remember and report what I found.I am going by word of mouth and the absence of a third pole space to deduce that the neutral is not interrupted at a typical GFCI breaker.