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Difference Between Relay and Circuit Breaker

Main Difference

The main difference between the relay and the circuit breaker is that Relay is a device that provides the signal to the circuit breaker in case of any fault in the power system, whereas Circuit Breaker is the device that breaks the signal after receiving the message from the relay.

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Relay vs. Circuit Breaker

Relay is a device or switch that used to sense any fault in the power system and send the signal to the circuit breaker. Whereas, the circuit breaker is a device or switch that breaks the signal after the detection of any fault in the system.

So, a relay is a type of sensing and switching device. It only used for sensing the fault and send a message to the circuit breaker. It does not involve in breaking the contact. On the other side, a circuit breaker is a disconnecting and isolating device. It consists of breaking the connections of the circuit.

A relay can be used to control or select one among a large number of circuits. On the other hand, the circuit breaker can only be used to control a single loop or circuit, just like a switch. Moreover, the relay may work as an amplifier. It can be used to change one signal into many signals. On the flip side, a circuit breaker may not be used as an amplifier. It can only receive a signal from the relay and act according to it.

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A relay works on low power input voltage whereas; a circuit breaker is an automatic device. It may work on both low and high power and voltage level. There are different types of the relay, e.g., Reed Relay, Hybrid Relay, Thermal Relay, Solid State Relay, and Electromagnetic Relay, etc. On the other hand, different types of circuit breakers are Minimum Oil Circuit Breaker, BOCB Circuit Breaker, SF6 Circuit Breaker, Plain Air Circuit Breaker, Axial Blast Circuit Breaker, and Vacuum Circuit Breaker, etc.

Relays used to isolate a low voltage circuit from high voltage one, in microprocessor to control heavy electrical load, to control multiple circuits, in automatic change over and as overload relays for motor protection, etc. On the other side, circuit breakers used in high and low current devices, industrial equipment and applications, home electrical wiring, power plants, electrical machines, & electricity sharing systems (GND), etc.

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Comparison Chart

RelayCircuit Breaker
A switch or sensing and monitoring device that is used to create or closed the contacts electro-mechanically or electronically is known as a relay.A protective device that used to create or break the course or circuit either automatically or manually in the result of faulty and normal conditions, for example, over-current and short circuit, etc. is called a circuit breaker.
Type of Device
A relay is a type of sensing and switching device.A circuit breaker is a type of isolating and disconnecting device.
Operation
It senses the fault in the power system and sends a message to the circuit breaker.Circuit breaker breaks the contact after receiving a signal from the relay.
Contact Breaking
It does not involve in breaking the contact.It is involved in contact breaking.
Number of Circuits Controlled
A relay can be used to control or select one among a large number of circuits.The circuit breaker can be used to control a single circuit, just like a switch.
Amplifier
The relay may also act as an Amplifier.A circuit breaker may not be used as an amplifier.
Voltage
A relay works on the low power input voltage.A circuit breaker is an automatic device that may work on both low and high power and voltage level.
Types
There are different types of the relay, e.g., Reed Relay, Hybrid Relay, Thermal Relay, Solid State Relay, and Electromagnetic Relay, etc.There are also different types of circuit breakers, e.g., Minimum Oil Circuit Breaker, BOCB Circuit Breaker, Axial Blast Circuit Breaker, SF6 Circuit Breaker, Vacuum Circuit Breaker, and Plain Air Circuit Breaker, etc.
Uses
Relays used to separate a low voltage circuit from high voltage one, in microprocessor to control heavy electrical load, to control multiple circuits, in automatic change over and as overload relays for motor protection, etc.The circuit breakers are used in high and low current devices, industrial equipment and applications, home electrical wiring, power plants, electrical machines, & electricity sharing systems (GND), etc.

What is Relay?

A relay is an interchange or a sensing and monitoring device that is used to create and close the contacts electro-mechanically or electronically. It used to sense any fault in the power system and send the signals to the circuit breaker to make or break the circuit. It is a switching device which is used to control the track of electricity. Relay controls the direction of power or electricity in the circuit. We can use a relay to on or off a loop instead of switching it manually.

A relay is used to switch a circuit, i.e., to activate or deactivate a single circuit among many connected to it. It controls the flow of current by an electromechanical assembly or a by the solid-state circuit. A relay works on the low power input voltage and guarantees full electrical isolation between the controlled and control circuits. The relay may also work as an Amplifier. It can be used to change one signal into many signals. For example, it may turn a signal of low voltage into a high voltage one, or vice-versa.

Some essential points should be kept in mind while choosing a relay for a circuit, i.e., type and number of contacts, voltage rating of contacts, contact sequence, coil current, assembly, and mounting, switching time, radiation-resistance, and environment.

Types

The relay is divided into different types, e.g., Reed Relay, Thermal Relay, Solid State Relay, Electromagnetic Relay, Latching relay, Mercury-wetted relay, Polarized relay, Ratchet relay, Contactor relay, Machine tool relay, Solid-state contactor relay, Buchholz relay, Forced-guided contacts relay, Hybrid Relay, and Overload protection relay, etc.

Uses

Relays used to separate a low voltage circuit from high voltage one, in microprocessor to control heavy electrical load, to control multiple circuits, in automatic change over and as overload relays for motor protection, etc.

What is Circuit Breaker?

A circuit breaker is a regulatory or protective appliance that used to create or break the circuit either automatically or manually in the result of faulty and normal circumstances, for example, over-current and short circuit, etc. It designed by using electromechanical techniques to prevent short circuits or power overload damage.

The circuit breaker has a solenoid in it and kept at a definite voltage level to keep the balance in the triggering mechanism. In case of any fault observed in the circuit, e.g., a short circuit or an overload, the switch is activated, and it discontinued the current flow. The circuit breaker may be switched back to on-again, after solving the problem in the electrical system.

Circuit breakers are available in different packages and sizes according to the requirements of the electrical system. The circuit breaker mechanism can be dipped in an insulating material, for example, oil, to improve the performance at higher voltage levels. Advanced circuit breakers are used in industries to regulate interruptions by capacitive switching, small inductive currents, and asynchronous switching.

A circuit breaker is an automatic device that may work on both low and high power and voltage level. It can be used to control one per circuit, just like a switch. A circuit breaker may not be used as an amplifier. It can only receive a signal from the relay and act according to it.

Types

There are also different types of circuit breakers, e.g., Minimum Oil Circuit Breaker, BOCB Circuit Breaker, SF6 Circuit Breaker, Axial Blast Circuit Breaker, Plain Air Circuit Breaker, and Vacuum Circuit Breaker, etc.

Uses

The circuit breakers used in high and low current devices, industrial equipment and applications, electrical wiring in homes, power plants, electrical machines, & electricity sharing systems (GND), etc.

Key Differences

  1. A switch that is utilized as a controlling and sensing means or appliance to create and close the circuit electro-mechanically or electronically is known as a relay. And a protective or controlling appliance that is utilized to create or break the contacts automatically or manually in the result of faulty and normal conditions, for example, over-current and short circuit, etc. is called a circuit breaker.
  2. A relay is a type of sensing and switching device. On the other hand, a circuit breaker is a type of disconnecting and isolating device.
  3. Relay senses the fault in the power system and sends a message to the circuit breaker conversely; Circuit breaker breaks the contact after receiving a signal from the relay.
  4. The relay does not involve in breaking the contact of the circuit. On the flip side, the circuit breaker involved in contact breaking.
  5. A relay can be used to control or select one among a large number of circuits. On the other side, the circuit breaker can be used to control a single circuit, just like a switch.
  6. The relay may also work as an amplifier. It can be used to change one signal into many signals. For example, it may change a signal of low voltage into a high voltage one, or vice-versa. On the other hand, a circuit breaker may not be used as an amplifier. It can only receive a signal from the relay and act according to it.
  7. A relay works on low power input voltage, while a circuit breaker is an automatic device that may work on both low and high power and voltage level.
  8. There are different types of the relay, e.g., Reed Relay, Hybrid Relay, Thermal Relay, Solid State Relay, and Electromagnetic Relay, etc. On the other side, there are also different types of circuit breakers, e.g., Minimum Oil Circuit Breaker, BOCB Circuit Breaker, SF6 Circuit Breaker, Axial Blast Circuit Breaker, Plain Air Circuit Breaker, and Vacuum Circuit Breaker, etc.
  9. Relays are used to separate a low voltage circuit from high voltage one, in microprocessor to control heavy electrical load, to control multiple circuits, in automatic change over and as overload relays for motor protection, etc. On the flip side, the circuit breakers are used in high and low current devices, industrial equipment and applications, home electrical wiring, power plants, electrical machines, & electricity sharing systems (GND), etc.

Comparison Video

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Conclusion

The above discussion summarizes that the relay is a switching device that is used to sense any fault in the electrical system and send a signal to the circuit breaker. On the flip side, the circuit breaker is a switching device that activates or deactivates the current flow according to the message received by the relay.

Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss