Earthing Three-Phase Circuits

Safety.

Earthing is must for any phase circuits, provided that the voltage is high enough to harm (living or non-living).

Your should earth a single phase or three phase circuit incase of a problem. For example, a wire comes loose from its terminal and touches the metal case of the machine. Earth is neutral in most situations so the circuit breaker should open if there is a fault because the current in this situation will be high. Earth is neutral because in most countries, just 'active' voltage is on the transmission wires. That is why you only see 3 wires not 4 wires carrying the voltage. The 3 wires carry the 3 phase voltage/current but not at the same time. Try a simple experiment for yourself: hammer a steel rod into the ground; attach a wire from the rod to a light globe [base or shield no problem]; connect another single wire to a power point and the light globe. Be careful [wear rubber gloves] and see what happens. ALWAYS JOIN THE METAL PART OF THE MOTOR ETC WITH A WIRE TO EARTH.

Do not under any circumstances conduct the experiment suggested by the post above.

There are numerous errors in his comment. This experiment could be life threatening.

Guest Quote "Earthing is must for any phase circuits, provided that the voltage is high enough to harm (living or non-living)."

Whaaat?

Oh! Life would be so beautiful, if the topic of electrical earthing could be made clear in a forum like this. We conduct a two-days duration training programme on electrical earthing. How to explain the entire contents in detail here?