cindy
so much has been said about the topic, that there isn't much left to say. but i'd like to pitch in the way i see it.

to understand the concept of grounding, first of all you have to understand the concept of the star point, or more common neutral. why isn't there a short circuit when all 3 phases are shorted together. the answer is that in a balanced three phase system (same amount of current flowing through all three phases, equal voltages, 120 degrees apart) then at one given moment the summ of the three voltages will be zero, thus if the three wires are shorted, a zero potential point is created which is called the neutral. So no current flows out of a zero potential point (neutral).

but there will be curent flowing from one phase to another.

i don't want to make this too long, if u have understood what i've tried to explain, tell me so and i will try to explain the rest of it to u.

happy new year [Linked Image]