How to calculate cable sizes in sq.mm. with using motor KW?
Any formula there?

Answer Posted / sagir siddiqui

First of all you need to verified full load current of motor,
How can you calculate:
Ex: 1 Motor - 20HP 3ph. 415V 50Hz, 80% efficiency

Cal: A= HPx746/(sqrt3xVoltxPFxefficiency)

=20x746/1.732x415x0.8x0.8

=32.43Amp.

We all know that a motor has 1.5 times starting current,

Then 32.43x1.5 = 48.65Amp

Now you can see in the current currying capacity of cable from manufacturer cable's list.

3.5 x 35 sqmm xlpe cable is sufficient for full load.

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