What is the difference between
Circuit Breaker and Relay?

In the electrical branch of engineering, a switch is a vital component. It helps to connect or disconnect the conducting path in the circuit. This interrupts the current from one conductor to another. 


Relays and circuit breakers play an important role in the circuit. 


Relays and circuit breakers may get a little intimidating to understand. There are many Relays and circuit breaker manufacturers in the market and it gets difficult to choose from.

This article will help you understand the difference between relays and circuit breakers and find the best circuit breaker for you. 

What is a Relay?


A relay is a switch in small current circuits. It is used to sense, detect and control the fixed and moving contacts electromagnetically or electrically. It is an electrical switch and its function is only to detect an error in the fault. 


It also acts as a protective device that alerts the circuit breaker when a fault is detected in the circuit. The circuit breaker then proceeds to respond to either make or break the circuit based on the information received. 


Relay is used to switch small currents in the circuit. Relay is found in devices such as small motors and solenoids. They are not power-consuming devices and produce low ampere voltage. 


Needless to say, Relay can control large amperes and voltages in a circuit through an amplifying effect as a small voltage amplifier when the current flowing through the relay coils is switched from the contacts. 


Relay comprises electromagnets and these electromagnets get energized when the current flows through it. 


When the voltage of the current is very high, the electromagnets can pull the contacts towards themselves when required. This breaks the circuit instantly.

Types of Relay:

What is a Circuit Breaker?


Circuit Breaker is an automated electrical switch that is designed to prevent and overcome any damage from short circuits and overload. The switch is electromagnetic. 

The circuit breaker works on the principle that when there are short-circuit or overload-related situations, the relay detects the fault, detects the amount of current, and transmits signals to the switch. 


The breaker design is created in a way that it performs the task of closing and opening the contacts within the system within a short duration of time.


The circuit breaker collects the signals and controls the opening and closing of the fixed and moving contacts to protect in the case of excessive current. 

The fixed and moving contacts work as electrodes inside the circuit. The circuit breaker can use the relay to determine any fault and react accordingly. Under normal conditions, the circuit is closed and does not open automatically. It only opens when a fault is detected in the system. The circuit breakers are broadly classified as hv circuit breakers (High Voltage)、mv breakers(Medium Voltage) and low circuit breakers.

Types of Circuit Breaker:

What is the Difference Between the Circuit Breaker and the Relay?


Even though Relay and Circuit Breaker services seem similar to each other. Here are some key differences that you need to note between both of them.


The prime difference between Relay and Circuit Breaker is that electrical device that sends off signals to the circuit breaker regarding the amount of current flowing through the circuit and senses any faults. The circuit breaker receives the signal and responds by deciding whether to interrupt the flow of current in the system or not. It breaks the signal when it receives the signal from the relay in the case of a short circuit. 


The differences between Relay and a Circuit Breaker is based on the grounds of the following:

The Relay consists of coils that act as electromagnetic fields. The Solenoid behaves as a moving part referred to as an Armature that closes and opens the fixed and moving contacts when the coils are energized.


The Circuit Breaker is an amalgamation of a Relay mechanism and an internal electromechanical mechanism that is designed to interrupt the flow of current in case of a short circuit.

The Relay conducts on low voltage and power input signals. It works with assured isolation during operation. 

The Industrial Circuit Breaker can operate on both low and high voltage power levels. It conducts automatically on load devices.

The operation of both the electrical switches is dependent on each other. 

The Relay is responsible to recognise the fault in the circuit and transfer the information regarding the same. 


The Circuit Breaker receives the signal and breaks the circuit in response to the signal to prevent any internal or external damage to the system.

Relay is used to detach the high voltage circuit from a low voltage circuit. It controls heavy electrical loads from the microprocessing unit. It helps to control multiple circuits at once. 


They are great in automatic change-over and motor protection in case of an overload. 


The Circuit Breaker is used in low and high current devices, in power plants, home electrical wiring, industrial equipment and applications, electrical machines and Electricity Sharing systems (GND), and many more. 

Relay is a handling and interpreting device which acts as a switch when needed.

The Circuit Breaker is a switch that acts as a disrupting and isolating device.

The Relay can work on one or more circuits at once. It can be used to select and control one circuit among many circuits. 


The circuit breaker can only be used for one circuit at a time as it is a switch.

The role of Relay is passive in the case of the contacts breaking. It only determines the error in the circuit and sends the signals to the Circuit Breaker.


The Circuit Breaker has an active role as it is responsible to disconnect the contacts by breaking them when it receives the signal.

The relay is a sensing and switching device. Thus, Relay is thus needed to switch circuits that hold small amperes of current 


The Circuit Breaker is a disconnecting and isolating device. Thus, the breaker can handle circuits of large amperes of current. 

Relay is an amplifying device for discrete signals. It has the capacity to turn a single signal into multiple signals. 


For example, It can turn a low-voltage signal into a high-voltage signal and vice versa.

Whereas, the Circuit Breaker cannot act as an amplifier for signals. It can only receive signals from a Relay and respond as per its encounter with the Relay.

Relay is a non-directional and directional device that controls the system. It sends the signal to the circuit breaker.


A circuit Breaker is a non-directional device that is responsible to act as a switching device.

It collects the signal from the Relay and responds accordingly.

The Relay cannot prevent arcs. It can collect information about it. The arc is developed between the contacts after the circuit detects an error before the short-circuit. These arcs are responsible to incur damage to the circuit internally and externally. They can re-strike if they keep moving within the system. Thus, Relay detects the arc and the level of current in the circuit. 


Circuit Breaker is built to contain mechanisms that help to prevent the formation of arcs in the circuit. They have different mediums such as Air, Oil, Vacuum, etc. that helps to not only disrupt the arc but also ensure that the arc is not formed again.

Relay is a switching device. It detects and controls the opening and closing of the contacts electromagnetically.


Circuit Breaker is responsible for interruption only. It responds to the detection performed by Relay.

The relay can be a part of a Circuit Breaker but the Circuit Breaker cannot be a part of a Relay. 


Relay and Circuit Breaker both use electromagnets but Circuit Breaker has multiple other mechanisms. For example Bimetal strips. 


Relay can divert electrical signals between any two diverse circuits. But, the circuit breaker is one-directional and can only determine the flow or stop the current within the system.

Table of Contents


Here is all you needed to know about the difference between Relay and Circuit Breaker. This comprehensive analysis is important to make sure that you make the right choice. Relay and circuit breaker play an interconnected role. One is a sensing device while the other is a protecting device. 


This information will assist you to find the leading hv circuit breaker manufacturers

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