Indeed, as they are in the UK, except they tend to be connected outside of the property, on a PME basis.
So the property must consider neutral and earth as totally separate.
What we must do is put an earth leakage (RCD - Residual Current Device) (balanced load checking) between the Live and Neutral and the various circuits.
Where the Earth wire / bond is the safety, to ensure that erroneous current is sunk to ground, rather than through some poor souls body.
(Path of least resistance etc)
Where (for example) the “RCD” should detect an absolute minimum of 30ma for a duration of 30ms
Better units detect 3ma for 3ms.
And the “DP MCB” is an over current device, normally 80 amp or 100 amp for domestic installations.
What this diagram doesn’t show (for the UK) is that outside of the property, the Neutral side is bonded to ground, rather than the earth being bonded to Neutral. (Which obviously it is, but it’s a “correct” way to think of it)
So that measuring Live / Hot to Neutral should give the same result as measuring Live / Hot to Earth (including physically sticking a copper rod into the ground {brown stuff in the back yard, for comedy reference})
The important detail I’m trying to make is that the Neutral and Earth are bonded together, before the main breaker.
If they were bonded after the main breaker / RCD, the earth safety would be utterly pointless.
MCB - Mains Circuit Breaker
DP - Double Pole
SP - Single Pole
RCD - Residual Current Detector
RCBO - Residual Current Circuit Breaker with Overcurrent Protection.
Example RCBO & RCD schematic, where the circuit is cut when the load is unbalanced across the breaker.
As you can see by the placement of the test circuit.
Live from after the coil, Neutral from before the coil
My apologies if I’m teaching anyone to suck eggs here.