I just want to use it to prevent short circuits while I'm working...

These are the maximum interrupting ratings of the equipment. Hopefully the available short circuit current is known and then the appropriate device installed...
You seem to imply that you are working on something while energized? Are you also then wearing any "Arc-Fault" protection?
What are you working on, can you provide a more detailed description?

I just want to protect from short circuit... I end up touching the live and neutral by mistake... so when that happens I don't want it to blow the main fuse.. I used a 10kA mcb. So when I short circuited it, it did trip but also blew the main fuse... how do I prevent it.

You could install current limiting fuses smaller than the ones in the main... so if you make a mistake they will blow first.
I think you may be asking the wrong questions, what is it you are working on that you need to work on while it's energized?

How can I contact u? Are you there on skype... can I talk to u... I'll explain better...

I would prefer you provide the explanation here...

What I want is just a thing to prevent anything to happen to the mains... so if I touch the live and neutral the mcb should trip and prevent anything else to happen..

Susheelsm

If I understand you, you are currently working on live (hot) circuits. Occasionally, you get a shock or sparks when hot and neutral are touched, correct?

The correct process to use is two fold, 1) remove all power from the circuit prior to working on it. This prevents injury to people and equipment.

2) If you must work on a live circuit, wear the proper safety equipment for the job you are doing. Also, any live conductors you remove, must be capped off immediately to prevent short circuits..

The best solution is to remove power from the circuit, not try to install a circuit breaker to protect the fuse. You or someone else can get killed playing on live circuits.

Don Not Do That!

A Short Circuit Coordination Study is needed to accurately determine the AIC rating of electrical equipment.

Don is right on here...
There is "no way" to safely work on a live circuit or should I say there is always a risk...
This risk is greatly increased when you are not sure about what you're doing...
Again, if you are not sure (which it sounds like) you should not work on anything live.

I'm just working on 230 volts... so its not a problem..! Which mcb will trip first a 16A mcb or a 10A mcb?

Before we go any further, please explain what your working on, why you are working live.

Any voltage over 50 volts is lethal.

Good morning.

Maybe you can consider sending us a picture of what you are doing. I for one don't want to be giving you advice that might get you killed or even worse might kill someone else.

What I suspect you are trying to do is to build a safety cable that you can use to protect the fuse with and trip fast enough that no one gets hurt.

That is not an acceptable solution. Either replace the fuse with a breaker then kill the power prior to working on the circuit or get the proper safety equipment!

You have not even given us the amperage of the circuit you are working on. That is more important than the AIR value.

230 Volts is lethal at any level of amperage! Are you trying to get some one dead by Christmas this year?

Are you here in the United States or are you in another country.

Susheeism...
No need to be shy here, this site has a variety of very bright professionals from differing backgrounds who offer good, relevant advice.
The question of how to go about protecting yourself and the equipment you may be working on is a good one and would be a good discussion for us all to consider.
Don't give up... we can help.