Circuit breaker:
A circuit breaker is a switch that is operated under on load and offloads conditions. The circuit breaker has fixed and moving contacts that are enclosed inside the porcelain vessel which is filled with arc interrupting media like air, SF6 gas, oil or vacuum. The circuit breaker interrupts heavy fault currents. The circuit breaker is one type of protective device. The main function of the circuit breaker is to protect the power system equipment from overload or short circuits.
Isolator:
An isolator is a switch that is operated under offload conditions only. The isolator has a fixed jaw and moving blades that are separated in atmospheric air. The atmospheric air is used as an arc interrupting medium in the case of the isolator. The isolator can not protect the power system equipment from overload and short circuits. The isolators are provided to physically isolate the equipment from the live parts of the circuit.
Difference Between Isolator and Circuit Breaker
| Circuit breaker | Isolator |
|---|---|
| The circuit breakers are designed to interrupt normal as well as short circuit current. | The isolator is not designed to interrupt any type of current. |
| The circuit breaker is on the load device so it can operate when supply is ON and also operates when supply is off. | The isolator is an offload device so it is operated when the supply is off. |
| The circuit breaker operated automatically based on the relay command. | The isolator can not operate automatically. it's operated manually only. |
| The earthing switch does not provide with the circuit breaker | The earthing switch does provide with the isolator. |
| The circuit breaker is used to protect a circuit from fault current. | The isolator is used to isolate or disconnect parts of the system. |
| The switching of circuit breaker gives rise to over-voltage because it is An load device. | The switching of isolator can not give rise to over-voltage because it is an offload device. |
| The circuit breaker is provided with an Insulating medium like air, SF6 gas, oil or vacuum. | The isolator does not require any insulating medium. |
| The circuit breaker can not be used to remove trapped charges from the system. | The isolator is used to remove trapped charges from the system. |
| The circuit breaker can not be used to re-route the power. | The isolator is used to re-route the power. |
| Oil circuit breaker, Vaccum circuit breaker, SF6 circuit breaker, air blast circuit breaker are some types of circuit breakers | The centre break, double break, pantograph are the types of isolators. |
| The circuit breaker has fixed contact and arcing contacts. | The isolator has a fixed jaw and moving blades. |
| The circuit breaker has a better thermal capability. | The isolator has less thermal capability than the circuit breaker. |
| The circuit breaker has a high withstand capability. | The isolator has a low withstand capability. |
| For circuit breaker protection relay is required for control purposes. | For isolator protection relay is not required for control purposes. |
| The circuit breaker has more cost | The isolator has less cost. |
| Higher safety in case of isolator | Highly trained technicians required in case of the isolator. |
| The physical status of contacts are not seen in the case of the circuit breaker. | The physical status of contacts are seen in the case of the isolator. |
Difference Between Isolator and Circuit Breaker
1. The circuit breakers are designed to interrupt normal as well as short circuit current. The isolator is not designed to interrupt any type of current.
2. The circuit breaker is on the load device so it can operate when supply is ON and also operates when supply is off. The isolator is an offload device so it is operated when the supply is off.
3. The circuit breaker operated automatically based on the relay command. The isolator can not operate automatically. it's operated manually only.
4. The earthing switch does not provide with the circuit breaker. The earthing switch does provide with the isolator.
5. The circuit breaker is used to protect a circuit from fault current. The isolator is used to isolate or disconnect parts of the system.
6. The switching of circuit breaker gives rise to over-voltage because it is An load device. The switching of isolator can not give rise to over-voltage because it is an offload device.
7. The circuit breaker is provided with an Insulating medium like air, SF6 gas, oil or vacuum. The isolator does not require any insulating medium.
8. The circuit breaker can not be used to remove trapped charges from the system. The isolator is used to remove trapped charges from the system.
9. The circuit breaker can not be used to re-route the power. The isolator is used to re-route the power.
10. Oil circuit breaker, Vaccum circuit breaker, SF6 circuit breaker, air blast circuit breaker are some types of circuit breakers. The centre break, double break, pantograph are the types of isolators.
11. The circuit breaker have fixed contact and arcing contacts. The isolator has a fixed jaw and moving blades.
12. The circuit breaker has a better thermal capability. The isolator has less thermal capability than the circuit breaker.
13. The circuit breaker has a high withstand capability. The isolator has a low withstand capability.
14. For circuit breaker protection relay is required for control purposes. For isolator protection relay is not required for control purposes.
15. The circuit breaker has more cost and the isolator has less cost.
16. Higher safety in case of isolator and highly trained technicians required in case of the isolator.
17. The physical status of contacts are seen in the case of the isolator. The physical status of contacts are not seen in the case of the circuit breaker.