What is the difference between circuit breaker and isolator?

Circuit breakers and isolators are both electrical devices used in power distribution systems, but they serve different purposes and have distinct functions.

1. Circuit Breaker:

   • Function: A circuit breaker is primarily designed to protect an electrical circuit from damage caused by overcurrents, such as short circuits or overloads. It automatically interrupts the flow of electric current when it detects a fault in the circuit.
   • Operation: Circuit breakers can be tripped manually or automatically. When a fault occurs, the circuit breaker opens its contacts, stopping the flow of current. This interruption protects the equipment and the circuit from potential damage.
   • Types: There are different types of circuit breakers, including air circuit breakers, vacuum circuit breakers, oil circuit breakers, and others. Each type has its own specific applications and advantages.

2. Isolator (Disconnector or Disconnect Switch):

   • Function: An isolator is primarily used to physically disconnect a part of the electrical circuit for maintenance or repair purposes. It is not designed to interrupt the flow of current under normal operating conditions or in the event of a fault.
   • Operation: Isolators have a simple on-off mechanism. They are manually operated and are used to isolate a specific section of the electrical system by opening or closing the contacts. Unlike circuit breakers, isolators do not provide protection against overcurrents.

In summary, the key difference lies in their functions and operations. Circuit breakers are designed to protect the electrical system by interrupting the current in the event of a fault, while isolators are used for isolating a part of the circuit for maintenance or other non-fault conditions. It's important to note that both circuit breakers and isolators may be used in conjunction within an electrical distribution system to ensure both protection and maintenance capabilities.