The value of the neutral current of
any three- phase, four-wire system
is equal to minus the phasor sum of
the line currents.

Example 1
Find the value of current flowing in
the neutral conductor for the
following load on a three phase,
star-connected distribution system.

Red phase 125 A at a power factor (pf) of 0.79 lagging
White phase 147 A at a power factor (pf) of 0.85 lagging
Blue phase 215 A at a power factor (pf) of 0.80 lagging.

0.79 lagging corresponds to 38° of lag red
0.85 lagging corresponds to 32° of lag white
0.80 lagging corresponds to 37° of lag blue.