How to calculate the maximum cable length?

The maximum permissible length for acceptable line voltage drop is calculated
by the formula:
L = Usquare/SA*S.K
___
where:
L : distance between the contactor and the control device in m
(length of the cable)
U : supply voltage in V
SA : apparent inrush power drawn by the coil in VA
s : conductor c.s.a. in mm2
K : factor given in the table below.
a.c. supply SA in VA 20 40 100 150 200
K 1.38 1.5 1.8 2 2.15
d.c. supply Irrespective of the apparent inrush power SA, expressed in W
K = 1.38

Released for:Schneider Electric India