why do european ride 3 phase breakers have 4 poles?

Question

why does the main breaker on most european rides with a delta connection have four poles phase A , phase B, phase C and neutral ?

Answer 1

" then the grounding will prevent people from becoming electrocuted."

And how do you explain that?

I think you are (dangerously) confused.

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Horn, I tried to answer your message but the system says that your address hasn't been confirmed - whatever that means.

So I'll put it here in case you spot it.



Referring to the original question - the four switched wires are three phases and neutral.

The neutral wire is connected to earth at the generator.

Your answer implies that this connection gives protection in the case of a fault. This is simply not the case.

In fact, the opposite is true.

It is because the neutral is connected to earth that a risk would be created if a phase wire were to make contact with an exposed conductive part of the equipment or apparatus being used.
It is the local connection, from apparatus to earth, which provides the protection, not the fact that the neutral wire is connected to earth.

If the neutral was not connected to earth there would be no risk at all, local earthing would be unneccesary and ground-fault indicators, or whatever they happen to be called this month, wouldn't be needed either.


(The "experts" have changed their name over here in the U.K. several times. They used to be called e.l.c.bs - earth leakage circuit breakers - then they became r.c.c.bs - residual current circuit breakers.)

Answer 2

I'm not sure what you're talking about, but if it's our power supply, then the neutral is for making technical equipment stable. The voltages may vary, but the neutral is always grounded. We don't really use the 3-phases much, but rather the converted form: 2-phase (plus the ground, which is not always used).

Answer 3

The fourth connection is a ground connection. It is to protect against faults so that if faults do occur, then the grounding will prevent people from becoming electrocuted.