Why do you need to ground a diesel generator?

Question

Electronics

I don't understand how grounding works. The potential difference between phase and ground is about 220 volts. And what is it between the phase of a diesel generator if it stands on a dielectric? And between the car battery and the ground?

Answer 1

A diesel generator does not have it, because the neutral (zero) is isolated, but in a household electrical network, zero is specially grounded at a transformer substation, just zero is connected to the ground and between it and the phase - 220, respectively, between the phase and the Earth - the planet - also 220, and no "magic", and in a car battery "-" can be grounded if the case is used as a ground and the tires do not provide proper insulation, then there may be 12 volts between "+" and ground.