How to make arc detector using optical fiber? is there any circuit for it.

 

Not enough information in your question. What arc? What does it need to do after detection? What voltages? this kind of thing

 

hi, fiber as in data (information) or do you mean light? as in some sort of lightening effect?

 

Not enough information in your question. What arc? What does it need to do after detection? What voltages? this kind of thing

we need it for detection of electrical arc inside of LV switchboard. After detection the relay circuit should operate.

 

hi, fiber as in data (information) or do you mean light? as in some sort of lightening effect?

Fibre as light, the light produced by the internal arcing of LV switchboard.

 

Is all other light totally excluded from the switchboard?

 

Is this to record a manufactured or incidental arc?
Depending on your set up it could include a simple LDR to fibre optic sensor and receiver.
One line description in the OP does not cut it.
Max.