<P> - Neutral conductor of a 3 - phase, 4 - wire system and the middle conductor of a 2 - phase, 3 - wire system to have minimum two separate and distinct earth connections with a minimum of two different earth electrodes to have the earth resistance to a satisfactory value . </P> <P> - The earth electrodes to be inter-connected to reduce earth resistance . </P> <P> - Neutral conductor shall also be earthed at one or more points along the distribution system or service line in addition to any connection at user end . </P> <P> Stray voltages created in grounding (earthing) conductors by currents flowing in the supply utility neutral conductors can be troublesome . For example, special measures may be required in barns used for milking dairy cattle . Very small voltages, not usually perceptible to humans, may cause low milk yield, or even mastitis (inflammation of the udder). So - called "tingle voltage filters" may be required in the electrical distribution system for a milking parlour . </P>

What is phase neutral and ground in ac