Power Supply MCB Selection

1. ( 6.2 A SMPS ) 6EP1333-1LD00

2. (PS 40A ) 6EP13373BA00

3. (PS20A) 6EP1336-3BA00

1. Input current / at nominal level of the input voltage 240 V / nominal value :- 2 A

From above to statment I have following query

1. If input current is 3.5A at 240 V then why they are recommending 10 A MCB. How it is calculated? Please guide me to understand.

From above to statment I have following query

1. If input current is 8 A at 240 V then why they are recommending 20 A MCB. How it is calculated? Please guide me to understand.

1. Input current / at nominal level of the input voltage 240 V / nominal value :- 2 A

2. Protection in the mains power input (IEC 898) :- Recommended miniature circuit breaker: from 10A,characteristic C,or from 16 A, characteristic B

From above to statement I have following query

1. If input current is 2A at 240 V then why they are recommending 10 A or 16 A MCB. How it is calculated? Please guide me to understand.

It as for same for 20A and 40 A power supply.

1.Input current / at nominal level of the input voltage 230 V :- 3.5 A

2.Protection in the mains power input (IEC 898) : -Recommended miniature circuit breaker at 1-phase operation: 10 A characteristic C;

Hi,

For providing overload and short circuit protection, datasheet is suggesting you to use different rating of MCBs.

Upto best of my knowledge the following statement should be true for C curve MCBs:-

C curve MCB: Overcurrent protection for general applications having range 3A to 5A. Magnetic release operates betweem 7 and 10 times the A rating.

Now let see how MCBs are selected:-
for 2A.. it should be ideal 2x3 = 6.0A nearest standard rating is 10A.

for 3.5A...selection is 3.5x 3= 10.5A again they have selected standard common rating 10A.

for 8A... here it goes again 8x3= 24A and hence 20A is again fast moving rating has been selected.

So, it is always advisable to select MCB considering overload current not based on nominal running current.