MCC Panel Current Carrying Capacity

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refer IEC 61439 and if it is not clear then do come back to the thread

can you tell the IEC standard formula for the calculation of Incoming rating of MCC panel

dear sir,

i am using the following formulae to calculate the Incoming rating of MCC panel

NOT Less than Incomer current rating = 25% of full load current of largest motor + Full load current of remaining motors

and

NOT More than Incomer current rating = 250% of full load current of largest motor + Full load current of remaining motors

I have selected inbetween the above ratings.

Please tell me am'i following the IEC standard

can you give the IEC standards document related to this MCC rating calculation

please help me.

Thanks,

with best regards,

rkram

If u ask me,i would simply help u to calculate yr MCCB incoming current rating.

Yr total load is 250kw(assume full load).P=root3VIcosO,O is phi.I=P/root3VcosO=250000/1.732x415x0.8=250000/575.024=434.76Amps. Multiplying 434.76 by a factor based on regulation(check yr Regulations on protective devices calculation),you will get 782.57Amps,then select MCCB range of 800Amps.

This will carry and protect yr total loads conveniently if u get a quality ABB/MITSUBISHI or other quality breakers.

Patrick Whowha

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