How to find out the Full load current [Relation between horse power and kilo watt] and how to select a proper cable [Power cable size selection chart]

In previous posts i have explained about electrical drawings, electrical panel component etc.. For smooth working of motor which is connected to the mcc panel, cable size selection has an important role. We have to consider lot of things for selecting a proper cable, like motor rating (Kilowatt,Horse power),Voltage(230v, 415 v etc.),Phase(Single, 3 phase),Temperature, Distance between motor and mcc.

Before that i will expalin how to find out the cable current rating.

1.Incoming suppy cable rating.

           Motor Full load current * 1.2
2.Inside cables – Motor circuit cable rating.
           Motor full load current * 0.7

Now you will be having a doubt how to find out the full load current of a motor?

Formula for finding full load current of a motor.

3 phase:
            Full load current=(746*hp)/(1.732*V*pf*eff) or KW/(1.732*v*pf*eff)
                                 hp=horse power
                                  v =Voltage
                                  pf=Power factor
                                 ef=efficiency
                              1 hp=745.7 W=0.746 kw

Single phase motor Full load current table [Horse power,Kilo watt]



Three phase motot Full load current table [Horse power,Kilo watt]

Cable size selection chart-Single phase

Cable size selection chart- Three phase

Learn to read Electrical drawing.
Motor control center [MCC] panel components.
Meters used in the MCC panel.