MCCB Selection

I have 3 phase 220V domestic power supply to my home by 16 mm aluminium 4 core armored cable. I have a sanction of 15KW load. With a concern for safety I intend to retrofit a MCCB of suitable rating. Request you to please guide me with respect to Amperage, Icu 240V, Icu 410V & Ics 415 V ratings required for the MCCB.

Let me know if you require any additional information.


asked 4/19/2016
Sandeep Dogra2
Sandeep Dogra

2 Answers

kVA = kW/0.8P.F

kVA = 15/0.8

kVA = 18.75kVA

I = kVA/(1.732x415V)

I = 18.75/718.78

I = 0.0260kA

I = 26A

I = 26A x 1.2 (overload factor)

I (MCCB,TP) = 32A   Icu = 10kA and Ics = 6kA will be more then enough.

32A MCCB, TP as Incoming breaker 

Further outgoing breakers for 220V system could be MCCB's, DP or SP as per requirement.




answered 5 months ago حسان نوابی 2
حسان نوابی

Hi friend,

            As per your given details MCCB is not required MPCB is enough. But you have MCCB for this load you chose the 50 A MCCB for 220 V. For 415 V 32 A MCCB is enough.    

 I=P/(SQRT(3)*220*0.85))       You take your loads I=15000/(1.732*220*0.85) it comes 46 A you take 15% extra 50 A MCCB is enough.

answered 6/16/2016 Dinesh137 2

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