What is the difference between isolator and circuit breaker.

Created: 2 years ago | Updated: 11 months ago

Updated: 11 months ago

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Difference between Isolator and Circuit Breaker

The following table highlights the major differences between isolator and circuit breaker-

Basis of Difference	Isolator	Circuit Breaker
Description	An isolator is a type of disconnecting switch which is used in an electrical circuit to ensure that the circuit is totally isolated from the supply mains.	A circuit breaker is a protective electrical device that works as a switch and is used to stop the flow of electric current through the circuit wherever necessary.
Circuit symbol
Construction	An isolator is a simple mechanical switch.	A circuit breaker consists of an electromechanical switch and a relay system in a single unit.
Operation Method	Isolator can only be operated manually.	Circuit breaker can be operated manually as well as automatically.
Type of device	Isolator is an off-load device, i.e. it can only be operated when there is no current flowing through the circuit.	Circuit breaker is an on-load device. Hence, it can be operated under power on conditions.
Functions	The major function an isolator is to disconnect the faulty part of an electrical system, so that it will be safe to repair.	The function of a circuit breaker is to protect the entire electrical system, if there is a fault. Also, it serves the function of a switch to cut off the supply wherever necessary.
Contacts	A typical isolator has main and moving arms.	A typical circuit breaker has main and arcing contacts.
Withstand capacity	Isolator has a low withstand capacity to currents.	A circuit breaker has high withstand capacity.
Insulation & quenching medium	Isolator does not need insulation or insulation medium. Isolator uses atmospheric air as arc quenching medium.	Circuit breaker requires insulation medium and arc quenching medium such as air, oil, vacuum, SF6 gas, etc.
Provide interruption	Isolator provides the interruption in the power supply only during inspection, maintenance or repair.	Circuit breaker interrupts the power flow during normal as well as fault like short-circuit and overload.
Removal of trap charges	Isolator can remove the trap charges.	Circuit breaker is incapable of removing the trap charges.
Need of relay system	Isolator does not require relay system for the operation.	Circuit breaker uses relay system to detect the errors in the system.
Earth switch	Single or double earth switches can be provided in an isolator.	No earth switch can be included in a circuit breaker.
Over voltage during switching	There is no rise of overvoltage during switching of an isolator.	There may be rise in overvoltage during switching of a circuit breaker.
Breaking capacity	The breaking capacity of isolator is less, as it cannot be used to break load faults.	The breaking capacity of circuit breaker is more, hence it can be used to break the load faults.
Safety	The isolator ensures the safety for technicians and switchgears.	Circuit breaker is not very safe, only professional and well trained technicians can operate it safely.
Cost	Isolator is less costly.	Circuit breaker is very expensive.
Applications	Isolators find applications only in industrial electrical systems to disconnect the circuit during maintenance	Circuit breakers are widely used in domestic, commercial, and industrial electrical systems for normal switching as well protection from fault.

Shajidul Islam

2 years ago

443

MCQ: 1k CQ: 1k

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What is the difference between isolator and circuit breaker.

Difference between Isolator and Circuit Breaker

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