DC Circuit Breaker Connected Position Selection

[stoui333]

Hi,

I have the below block diagrams as an example.

Question 1: Circuit breaker should be placed on the input or on the output of the DCDC converter ?
I suppose both will work but whats the effect in case of a short?

Question 2: How do i calculate the circuit breaker amperage selection?
Question 3: The estimate power consumption should be the peak or average for the circuit breaker selection?
Question 4: In order to calculate the estimated Peak power consumption of multiple boards/units/modules i sum all peak power consumption values of there datasheets and multiply my a safety % factor?
Question 5: How to avoid circuit breaker trip from in-rush & surge currents?

Thank you,
stoui

 

[Bluejets]

Started to answer this but then realised it looks like homework.

 

[WHONOES]

Consider what might happen in each situation.