MCB Selection

You need to specify what you mean by MCB. In IEC-land a MCB is a miniature circuit breaker, in other places this acronym has a different meaning.

You will also need to know the prospective short-circuit current of the supply that you are planning to connect your breaker to.

You need to understand what a MCB does and is intended to do.

You obviously do not!

Google "MCB function".

Then Google "electrical codes".

Until you have some inkling of what you are doing, you are a danger to society.

As always, using the electrical code applicable to the jurisdiction in which the installation is to be made. In the UK, for example, it would fall under BS7671. The consequences of not doing so include invoking a measure of unpopularity with the facility's fire insurers and the relatives of the individuals that get killed.

Remember the circuit protective device is there to protect the WIRING.

If in doubt, consult a qualified Electrician.

This is not about just a formula; there are further questions: Is the load inductive (e.g., motor), resistive (e.g., heater), or capacitive? There are different factors for each. Is the load continuous? There may be a factor for that, also. As already mentioned, this depends on the local regulations. (Apologies for lack of paragraphs; I am temporarily saddled with a crummy browser.)

Definitely - consult a qualified Electrician without further delay!

It doesn't matter what the loads are as it is the wiring that the MCB is supposed to be protecting.

Selected Molded Case Breaker (MCB) values are dependent on the following:

1. Location/position of MCB in electrical system.

2. Rated current of the circuit conductors being protected.

3. Expected maximum current inrush of the circuit.

4. Speed of circuit interruption required to protect the equipment being serviced by the MCB.

5. Ambient environment conditions. (mean temperature, humidity, chemicals,?)

6. Type of system voltage (AC or DC).

7. Physical limitations of the applications.

These and all other requirements are identified in the local code documentation specific to the area/location.

Anyone who uses BS7671, such as a qualified Electrician, can. And it's not so much a formula, more a protocol.

Not really. As mentioned both earlier and later, it is not just a formula.

You don't understand English do you?

Circuit breakers have nothing to do with efficiency!

Use a search engine to research breakers and READ THE CODE BOOK!

Don't be so stubborn!

Do your own work!

Not unless you explain the numbers in the table. Moreover, breakers are not chosen on the basis of "efficient operation".

Experts i am very new in this component selection. Therefore i am totally confused.

I know only thing that i need to use circuit breakers for the above systems also mentioned the information i have with me.

Now i am using search engine to study.

You need to first follow local codes, but that is not your only problem.

Being that you said this is going to be installed in the USA, the information you need can be found in reading and understanding the National Electric Code (NEC), available from the NFPA (National Fire Protection Agency) as document NFPA-70. In addition, if this is an assembled system as an industrial control panel, the NEC will require that it bear an approval label from a Nationally Recognized Yesting Laboratory (NRTL), a list of which can be attaind from the government office called OSHA (Occupational Safety and Health Administration). The most well known NRTL is UL, and in fact the other NRTLs use the test standards of UL anyway. What you need from UL is a "UL-508" listing. It is very expensive to have UL test a one-off panel, it is far far more effective to hire what's referred to as a "UL-508 shop", who can design and build your panel to meet UL requirements, then apply the necessary label to it. By doing that, you are assured not only of the panel being acceptable to UL, but it will be default meet all NEC requirements. There are thousands of UL-508 shops in the US and Canada, but there are also some spread out across the world. You can go to UL.com to get a list.

Both the NEC and UL-508 contain the rules for the proper selection of MCCBs.

And just for semantic clarity, MCB means "Main Circuit Breaker" over here, not "Molded Circuit Breaker", which would be confusing. So we use MCCB for Molded CASE Circuit Breaker. MCB elsewhere in the world means Miniature Circuit Breaker. the use of OEC style Mini CBs is fraught with issues and pitfalls over here when it comes to UL listings, so I would highly recommend using MCCBs unless you know and understand ALL aspects of the site installation and power system requirements.