How to calculate the rating of incomer for the multiple outgoings?
e.g Outgoing loads 5HP S/D starter-7Nos; 10HP S/D satrter-5 Nos; 20HP S/D starter-8 Nos; 250A TP MCCB-2 Nos; 63A TP MCCB-8 Nos; 4HP DOL starter-12 Nos; 3HP DOL starter-3 Nos; 1000W heater-1No.
First of all try to find out the full load current of all the loads and sum it up thereafter you can use a incomer of that value.(If the sum is 600A you may need to use a 630A incomer)
There is another way of selecting incomer it is to calculate the total load in watts thereafter using the three phase power formula, you can find out the line current and add some 20% in it to avoid unnecessary tripping on over load (P=sqrt of 3*V*I*PF and consider power factor PF as 0.8)
