Circuit breakers are everywhere. These electrical switches are installed in the power systems of our homes, offices, electric vehicles, and infrastructure to protect us from short circuits or overloads. Many of us don't have any idea what a circuit breaker is, but it is essential to support our daily routines.As the demand for electricity and electrical devices rises, the necessity of circuit breakers also increases. You can order such a circuit breaker from the Lauritz Knudsen. It ensures the safety and effective distribution of electricity and emphasizes energy efficiency and technical innovation.

In this blog, let us explore what is circuit breaker, the types of circuit breakers, the function of circuit breakers, and its applications.

What is a Circuit Breaker?

A circuit breaker is a switching device created to control or protect electrical power systems when a fault, such as a short circuit or overload, occurs. If you don’t have a circuit breaker, parts of the power system could be damaged, overheated, or catch fire. To make things clearer, circuit breakers do the same thing as fuses. Fuses are one-time utility devices that should be replaced after overload, whereas circuit breakers can be reset manually or automatically as switches.

What are the Types of Circuit Breakers? 

Circuit breakers can be of different types depending on the installation location, quenching medium, voltage level, and operating mechanism.

Installation Location-Based Circuit Breakers 

• Outdoor Circuit Breaker: These are designed to be fixed on the outside of the building and are made to survive challenging weather conditions.

• Indoor Circuit Breaker: As the name suggests, indoor circuit breakers are intended for installation inside buildings. They can be run at low and medium voltage levels and are enclosed in a weatherproof material.

Quenching Medium Circuit Breakers 

• Oil Circuit Breaker: Mineral oil is the quenching medium used in oil circuit breakers, as it has high cooling properties. The contacts are immersed in the oil-filled chamber. When the contacts are open, an arc is formed in the oil. Then, the oil is decomposed into hydrogen gas, reducing the temperature and pressure of the arc. Oil circuit breakers are used in high-voltage areas such as substations.

• Air Circuit Breaker: Compressed oil is the quenching medium used in air circuit breakers as it has high thermal conductivity. The contacts are enclosed in an airtight chamber connected to an air compressor. When the contacts are open, air bursts into the arc and blows away from them. This cools down the contacts and removes the ionised particles from them.

• SF6 Circuit Breaker: Sulphur hexafluoride gas is the quenching medium used in SF6 circuit breakers, as it has arc-extinguishing properties. The contacts are placed in a sealed chamber attached to a gas at low pressure. When the contacts are open, the gas flows on the arc, reducing the conductivity and cooling down the contacts. It is used in medium and high voltages.

• Vacuum Circuit Breaker: Vacuum is the quenching medium used in vacuum circuit breakers. The contacts are enclosed in a metal or ceramic chamber evacuated to a very low pressure. When the contacts are open, an arc is initiated in the vacuum and extinguished.

Voltage Level-Based Circuit Breakers  

• High Voltage Circuit Breaker: These are used in power stations and transmission lines. A high-voltage circuit breaker handles power above 72.5 kV and needs strong insulation. It uses SF6 gas or vacuum to put out arcs. It plays a key role in protecting expensive equipment from major faults. These are common in the application of circuit breaker setups in large grids.

• Medium Voltage Circuit Breaker: Medium voltage circuit breakers are often used in office buildings, factories, and small grids. They operate between 1 kV and 72.5 kV. They give balance, strong protection, with moderate size. These are used in several applications of circuit breaker systems due to their easy maintenance and reliability.

• Low Voltage Circuit Breaker: These are found in homes, schools, and small businesses. They work below 1 kV and are easy to install. They protect wires and appliances from overloads or faults. You’ll often see MCBs and MCCBs in this category. Most uses of circuit breakers in homes come under low-voltage protection.

Operating Mechanism-Based Circuit Breakers  

• Spring-Operated Circuit Breaker: Mechanical energy is stored inside the spring, which is locked by a latch. The latch is released when the circuit breaker gets a switching signal, and the mechanical energy opens the contacts.

• Pneumatic Circuit Breaker: Compressed air opens the contacts. It is stored in a tank. On receiving the switching signal, the air is released to open the contacts.

• Hydraulic Circuit Breaker: It is a type of circuit breaker that uses hydraulic fluid pressure to assist in the operation of opening and closing electrical contacts. It is designed to protect electrical circuits from overloads and short circuits, especially in high-current and heavy-duty industrial applications where reliability and precise control are critical.

Function of a Circuit Breaker

The function of a circuit breaker is not just to stop or allow power. It’s mainly about protection. It protects people, devices, and systems from damage caused by overload, faults, or electrical fires. Without this device, electrical setups would be unsafe and unstable.

• Fault Detection: Circuit breakers act when something goes wrong. If there’s a short circuit or overload, the breaker quickly identifies the fault and stops the current before any harm is done. This is one of the main uses of a circuit breaker that prevents serious electrical hazards.

• Load Control: They also help to manage the electrical load. If too much current flows through a line, the breaker disconnects the flow to avoid overheating. This is useful in preventing equipment failure and managing power properly.

• Manual Switching: Circuit breakers aren’t only automatic. You can switch them manually, too. This makes it easy to isolate parts of the system during maintenance or when you want to shut off power to a specific area.

• Isolation: When a fault is detected, the breaker disconnects only the part where the problem is. It keeps the rest of the system working. This way, the damage stays limited and you don’t lose full power everywhere.

• Equipment Safety: Circuit breakers are built to shield devices from harm. By disconnecting the power during faults, they help increase the life of appliances and other electrical machines. It’s one of the basic uses of circuit breaker systems in homes and industries.

Working Principle of a Circuit Breaker 

The working principle of a circuit breaker is based on fault detection, mechanical movement, and arc suppression. When too much current passes, the device breaks the connection using its stored energy. The current stops, preventing any further risk.

• Sensing Current: When the current goes above safe levels, the breaker picks up the fault. It uses sensors and magnetic fields for this purpose. As soon as it senses a problem, it prepares to cut the flow.

• Energy Release: Inside the breaker, energy is stored in springs, compressed air, or fluids. Once a fault is found, this energy is released. It pushes the contacts apart fast, which stops the current. This shows how simple the working principle of a circuit breaker can be.

• Opening Contacts: Two contacts, one fixed and one moving, are forced apart. This action breaks the path of electricity. The contact movement must be quick, or else the arc can cause damage.

• Arc Control: When contacts open, a bright arc forms between them. This arc is hot and dangerous. The breaker puts it out by using air, oil, gas, or vacuum. These materials cool the arc and stop it from burning anything nearby.

• Resetting: After the fault is solved, you can reset the breaker. This brings the contacts back together and lets current flow again. This is one reason electrical circuit breakers are more useful than traditional fuses.

How does a Circuit Breaker work? 

The circuit breaker automatically opens the circuit and cuts off the flow of electricity when an excessive amount of electricity, referred to as fault current, passes through it. Let us understand how a circuit breaker accomplishes this in detail.

• Fault Detection: The circuit breaker consists of two contacts, one fixed and the other moving. They always physically touch each other, which is called a closed condition that allows the current to flow continuously. Mechanical pressure applied on the moving contact initially puts the circuit breaker in the “ON” state. A switching signal is given if the circuit breaker detects a fault condition, such as a short circuit or overload.

• Release Potential Energy: The operating mechanism stores potential energy released when the switching signal is provided to the breaker. We can store the potential energy with hydraulic pressure, compressed air, or deforming metal springs. Regardless of the source, potential energy should be released during the operation. After the total energy is released, it should be stored again in the operating mechanism by an air compressor, spring charging motor, or other suitable means.

• Separate Contacts: The two contacts, a fixed and a moving contact, are in closed conditions opened by the potential energy. The released potential energy separates the two contacts by allowing the moving contact to slide rapidly.

• Arc Formation: The separation of two contacts creates an arc. It is a highly ionised (electrically charged) and conductive plasma. If not extinguished properly, it can damage the two contacts and other equipment surrounding it and even catch fire.

• Arc Quenching: The process of extinguishing the arc is called arc quenching. Circuit breakers use various methods to quench arcs, such as replacing the ionised medium, compressing, or cooling. The quenching medium depends on the current rating and voltage level of circuit breakers.

• Interrupt Current: Interrupt current (also called interrupting current or breaking current) is the maximum electric current that a circuit breaker can safely stop (interrupt) without damage when a fault such as a short circuit or severe overload occurs.

• Reset Circuit Breaker: Reset circuit breaker refers to the process of restoring a circuit breaker to its normal operating condition after it has tripped due to overload or short circuit. Once the fault is cleared, the breaker is manually or automatically reset, allowing current to flow again.

• Connect Contacts: Connect contacts are the conductive parts of a circuit breaker that touch each other to complete the electrical circuit. When the contacts are closed, current flows normally through the breaker.

What are the Uses of Circuit Breakers?

Electrical circuit breakers have several uses in various fields. It includes,

• Commercial: Circuit breakers protect against faults, overloads, power surges, and other hazards in business premises, including hospitals, malls, hotels, and offices. They also enable automation and energy management.

• Power Generation: Circuit breakers prevent damage to transmission lines from switching surges, lightning strikes, faults, etc. They also permit power system network sectionalisation and load shedding.

• Rails: Faults, overloads, short circuits, and other hazards are guarded against by circuit breakers on rail vehicles, which include trains, trams, metros, etc. They also enable motor regenerative braking and traction control.

• Industrial: Industrial equipment, including pumps, compressors, fans, and so on, is shielded from defects, overloads, phase imbalances, and other hazards by means of electric breakers. They also enable motor soft starting and speed control.

• Power Distribution: Circuit breakers protect feeders, induction motors, distribution transformers, and other equipment against overloads, low voltages, and other problems. Additionally, they provide demand response and load management for power system loads.

Applications of Circuit Breakers  

Circuit breakers are used in many areas. They don’t just stop current; they make electrical systems safer and smarter. Let’s see where you’ll find these in daily life and technical setups.

• Homes and Offices: Circuit breakers protect wires, sockets, and appliances from overheating. They’re used to stop sparks and short circuits, which could lead to fires. This is one of the most common functions of a circuit breaker system.

• Industrial Machines: Factories use breakers to protect heavy equipment like motors and pumps. They prevent damage from phase loss, short circuit, or overloads. These are vital in the application of a circuit breaker in industrial zones.

• Power Grids: They guard large transmission lines, transformers, and substations. Circuit breakers help manage load and isolate faults in one section without cutting power to the rest.

• Commercial Buildings: In malls, hospitals, or hotels, breakers help balance power and offer safe shutoffs during faults. They also support better energy management.

• Transportation: Trains, metros, and electric vehicles use breakers to stop faults. They also support control systems and ensure passenger safety.

What are the Pros and Cons of Circuit Breakers?  

Circuit breakers are widely used protective devices in electrical systems. Like any electrical component, they offer several advantages as well as some limitations.

Pros of Circuit Breakers 

• Reusable and Resettable: Unlike fuses, circuit breakers can be reset after tripping, making them cost-effective and convenient for long-term use.

• Fast and Reliable Fault Protection: Circuit breakers quickly interrupt current during overloads and short circuits, preventing damage to wiring, equipment, and appliances.

• Improved Electrical Safety: They significantly reduce the risk of electric shock, fire hazards, and electrical accidents, ensuring safety for people and property.

• Easy Fault Identification: A tripped breaker clearly indicates a fault in the circuit, making troubleshooting faster and easier.

• Wide Range of Applications: Circuit breakers are available in various types and ratings, making them suitable for residential, commercial, and industrial power systems.

Cons of Circuit Breakers  

• Higher Initial Cost: Circuit breakers are generally more expensive than fuses, especially for high-current and high-voltage applications.

• Complex Construction: Some circuit breakers have mechanical and electronic components, increasing design complexity and maintenance requirements.

• Requires Periodic Maintenance: Industrial and high-voltage circuit breakers may require regular inspection and servicing to ensure reliable operation.

• Slower Than Fuses in Certain Faults: In some cases, fuses can respond faster than circuit breakers during very high fault currents.

• Possible Mechanical Wear: Frequent tripping can cause mechanical wear of contacts, reducing performance over time if not properly maintained.

How to Choose the Right Circuit Breaker? 

Choosing the right circuit breaker is important. If the specs don’t match your setup, it might not work as needed during faults. So, let’s see how to choose the right circuit breaker for your system without getting too technical.

• Voltage: You have to match the breaker’s voltage rating with your system. For example, a low-voltage breaker won’t work in a high-voltage area. Always check this first when looking at different types of circuit breakers.

• Current Rating: The breaker must handle your usual current without tripping too early. But it should also trip during overload. Getting this wrong can lead to either no protection or too many unwanted trips.

• Where You Use It: A breaker used in a home won’t suit a factory. You must choose based on the place and the job it’s meant to do. This step is key in understanding how to choose the right circuit breaker.

• Quenching Type: Each breaker type uses a different arc-quenching method. Some use oil, some gas, some air. The right one depends on how much current you're dealing with and what the environment is like.

• Installation Conditions: If it’s for outdoors or a place with dust or heat, go for one made to survive those conditions. Environmental factors also affect the life and working of electrical circuit breakers.

Also Read: MCB (Miniature Circuit Breakers) Guide - Types, Sizes, And Uses

Conclusion 

Circuit breakers are essential for safeguarding electrical and human lives by interrupting abnormal current flow and returning to normal after rectifying the fault. They are of many types based on the quenching medium, operating mechanism, voltage level, and installation location.

You can choose them from our reliable electrical store. We have been active in manufacturing and distributing premium electrical products. Our circuit breakers ensure reliable protection and control of electrical power systems. Stay safe with the Lauritz Knudsen range of circuit breakers – protecting your home and office from potential fires and sparks! We have an extensive range of circuit breakers suitable for different purposes. Check out our offerings and choose our products for durability and quality.

FAQ About Circuit Breaker 

Q1. How to Install a Circuit Breaker?

Ans. Switch off the power before installation. Fit the breaker into the panel slot, connect the wires, and tighten the terminal. Turn on the power and test. This is a simple guide on how to install a circuit breaker safely.

Q2. Can circuit breakers be used to protect against electrical fires?

Ans. Yes, circuit breakers help stop fires caused by overload or short circuits. When unsafe current is detected, they disconnect the power. This function of a circuit breaker prevents the overheating of wires.

Q3. How do circuit breakers contribute to energy efficiency?

Ans. Breakers help manage how much energy is flowing and prevent power loss. They stop overloads, reduce downtime, and make systems run smoothly. These uses of circuit breakers help improve long-term energy savings.

Q4. What safety measures do modern circuit breakers offer?

Ans. New breakers come with features like ground fault detection, thermal sensors, and remote control. These additions increase safety and reduce the chance of electric shock or system failure.

Q5. What is the difference between an MCB and an MCCB?

Ans. MCBs are used in smaller loads like homes. MCCBs are bigger and handle higher currents. MCCBs are adjustable and better suited for industries. These are two different types of circuit breakers with different purposes.

Q6. Is a fuse better than a circuit breaker?

Ans. Fuses break once and need replacement. Circuit breakers can be reset many times. Also, breakers are faster and safer. So for most situations, circuit breakers are a better choice.

Q7. How does a circuit breaker trip?

Ans. When too much current flows, the internal mechanism pushes the contacts apart. This stops the circuit. That’s how breakers prevent overheating and damage, one of the main functions of a circuit breaker system.