how to get size of MCB of a 3 phase 1Kw gas heater

[lyncher366]

how do i get size of MCB of a 3 phase 1Kw gas heater. does it have to go through an RCD, help please its for an exam iam doing,thanks

 

[i=p/u]

for a three phase circuit,
Current (3 phases):
I = P / √3 Vl×cos φ
or
I = P / 3 Vp×cos φ

P = power (watts), I = current (amperes), Vl = line voltage (volts), Vp = phase voltage (volts), φ = power factor angle between voltage and amperage

Translated:
Current = Watts / √3 Line Voltage × cos Power Factor Angle
Or
Current = Watts / 3 Phase Voltage × cos Power Factor Angle

 

[lyncher366]

good man thanks for replying.
I=1000/692.82
I=1.44amps

so i can use 1.5mmsq cable and a 10amp MCB is that right.