Circuit breaker

1. A circuit breaker for high voltage applications, comprising:

at least one breaking unit,

a supporting insulator having one end on ground potential and the other end on high voltage potential, and the end on high voltage potential is mechanically connected to the breaking unit, and

a fiber optic sensor for sensing current through the breaking unit, characterized by

the supporting insulator is removably connected to the breaking unit,

said sensor has an optic fiber coil arranged in the high voltage end of the supporting insulator, and

the circuit breaker comprises means for conducting current from the breaking unit to the sensor so that the current passes through the sensor coil, said means for conducting the current comprising at least one insulator element arranged to prevent the current from flowing directly from the breaking unit to a terminal flange, and a bypass connector conducting the current from the breaking unit to pass through the sensor and then further to the terminal flange.

2. The circuit breaker according to claim 1 , wherein the circuit breaker is a disconnecting circuit breaker.

3. The circuit breaker according to claim 1 , wherein current from the at least one breaking unit is conducted to an additional flange connected to the supporting insulator.

4. The circuit breaker according to claim 3 , wherein the sensor is provided in the additional flange.

5. The circuit breaker according to claim 1 , comprising spiral contacts for transferring current to the sensor.

6. The circuit breaker according to claim 1 , comprising a current conductor which is insulated from the terminal flange to divert current to the supporting insulator.

7. The circuit breaker according to claim 1 , comprising an additional breaking unit and a house interconnecting the at least one breaking unit, the additional breaking unit, and the supporting insulator, and an insulation between the at least one breaking unit and the house to divert current to the supporting insulator.