Answer / asutosh

the breaker rating depends on
1 total incoming supply in kV.
2 total power requirment in kVA.
3 the short circuit power for perticular supply.

Answer / r p payasi

kVA rating=Sqrt(3)*KV*Fault current(max)

so required is
1.Voltage of line
2.max fult current

Answer / thileepan

above answer is exact

Answer / p l narayana

circuit breakers are selected in kva which can calculated
from the fallowing equation
KVA Rating=3^0.5*phase voltage*short circuit current*1.25

Answer / jignesh

The C.B. rating r depend on load connected with it.
For three phase supply

I = KW/((ROUT3)*V*COS fi)

From we getting the current for given line then w easily
find C.B. rating with this current.

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