Load Break Switch: How It Works, Key Features & Applications

When there are chances of downtime or damage to equipment, it becomes challenging to safely manage power. But you have no need to worry, a load break switch can help in this situation. In this guide, you’ll learn how it works, its importance, and how the right selection can help you avoid a lot of trouble. So, let’s get started!

1) What Is a Load Break Switch?

A load break switch is an electrical switch that breaks a circuit and removes load when power is switched on. Simply put, it allows you to disconnect power safely without equipment damage or safety risks. It is used in medium voltage power systems and helps to control flow of electricity reliably.

Actually, the load break switches are used to disconnect and connect circuits while current is flowing. This is different from a disconnector, which is used when there is no load on the system. We can say that the load break switch is designed to take the strain of load break switching and is capable of breaking current without electrical arcs damaging the system.

These switches can be found in substations, switchgear panels, and even in outdoor installations. Wherever there is a need to control, isolate, or protect sections of an electrical system, these switches can be found.

Well, they are particularly helpful in periods of maintenance or in emergency cut-off situations. When used as instructed, these switches can help make sure that your system remains undisturbed and running smoothly.

Today’s load break switches handle medium voltage, usually from 1kV to 36kV. Apart from this, some of these are additionally offered with optional manual or motorized operation, fault protection, and gas insulation which allows better control of arc.

2) How Load Break Switches Operate

Every load break switch has a very specific purpose, which is to break an electrical circuit. Here’s a brief outline of how it does that.

Step 1) Normal Flow of Electricity

In the case of the switch being closed or in the “on” position, current flows through the switch like in any other circuit. As the various components of the system are powered, the switch remains connected.

Step 2) Breaking the Circuit

When the switch starts to open, the contacts begin to separate. Because current is still present, this action may produce an arc—essentially, a small electrical flare jumping across the gap.

Step 3) Arc Control

The switch incorporates other means to deal with the arc, referred to as arc-quenching mechanisms. These may be: air chambers, special contact configurations, or even SF₆ gas in sealed models. Their purpose is to the features that cool the arc and stretch it, breaking it quickly and safely.

Step 4) Full Disconnection

The moment the contacts are de-energised and the switch is opened, the arc is extinguished, and full separation has occurred. There is no electric current flowing through the circuit. The portion of the system that was connected to the switch is now isolated and is safe to work on.

Step 5) Reconnection (When Needed)

To restore power, the switch is closed by the operator. This closes the circuit, and the system may be powered on.

3) Key Features & Advantages

There are a lot of useful features of load break switch with a number of advantages. Let’s have a look;

Key Features of Load Break Switches

• Adjustable Load Break Switch (LBS) features: Several characteristics make a load break switch a vital component in electrical systems. Such features enhance the operation by making it more safe, simple, and dependable.

• Load-Breaking Capability: Current flow is fully maintained when the switch is functioning. This current flow is maintained until the switch breaks the current flow safely without any damage.

• Methods of Blowing the Arc: While breaking current flow, a switch can generate the electric arc. And, the material and gases to stop the arc includes, air, vacuum or SF6 gas.

• Manual Versus Motorized: Current flow can be maintained or broken by either a manual switch or a motorized version. Moreover, motorized versions can be used for remote control, a feature that is useful in high risk and difficult places to access.

• Precise and Clear Zoning: Precise zoning in most load break switches shows the switch is either opened or closed. So, this allows for easy perception of the state of the switch.

• Strong Build and Insulation: Strong and high-quality materials used in the production of these switches includes insulation to protect against heat, pressure and extreme weather conditions.

• Reduced Size: Reduced modern switch size leads to easy installation in cabinets and panels.

• Appropriate Use for Intermediate Voltage: Ideal for systems from 1kV to 36kV, these switches are most useful for the intermediate voltage range.

• Safety Features: Some models incorporate interlocks or automatic tripping mechanisms as a further safeguard against incorrect operations.

These safety measures enhance the dependability and efficiency of the load break switch while also ensuring it remains safe and reliable in a wide array of applications.

Advantages of Load Break Switches

With regard to safety, cost, and functionality, the benefits a load break switch offers are remarkable.

+ Safe Operation: Safety is certainly one of the foremost benefits. During operations, the load break switch can sever the circuit without generating sparks or any form of electrical hazard. With this battery switch, the maintenance and emergency operations are much safer as well.

+ Quick Isolation of Circuits: You are able to quickly isolate various components of the power network for maintenance or enhancement works. This minimises downtime and, in addition, reduces the necessity to switch off the entire system.

+ Reduced Equipment Damage: The arc-quenching capability safeguards the equipment from electrical surges or thermal damage that may be incurred while switching on the load. This improves the longevity of the system’s components.

+ Lower Maintenance Needs: A number of load break switches are designed for almost no maintenance, and this efficiency reduces the burden of sustained expenses across the entire electrical system. This is especially advantageous for large systems that incorporate a multitude of switches.

+ Simple to Use and Install: With these switches, it is possible to achieve efficient resource and time management. Moreover, daily use is effortless and stress-free due to the smooth mechanisms and clear indicators following installation.

+ Economical Alternative: Load break switches are priced lower than a circuit Electric breaker. Therefore, for those that do not require the full functionality of a breaker, a load break switch is a safe and reliable alternative at a much lower price.

+ Durability: The robust design of these switches can endure a lot of wear and tear, meaning they do not require frequent replacements.

+ Multidisciplinary Uses: These switches can be employed in indoor panels, outdoor poles, substations, and in more industrial settings. This versatility is helpful for different project requirements.

Due to these benefits, load break switches are a smart option for the reliable management and protection of electrical systems.

4) Types of Load Break Switches

Based on the operation methods and different media used for extinguishing the arc, Load Break Switches are classified into different types. It is of utmost importance to consider where and how you plan to use it. The following are the most commonly used types:

i) Air Load Break Switches

This type of switch employs compressed air to blow the arc when the switch is opened. It has a simple design that makes it suitable for both indoor and outdoor systems. Air load break switches are well suited for medium voltage systems and are frequently mounted on poles or inside cabinets.

ii) SF₆ Gas Load Break Switch

Switches of this type use SF₆ gas to extinguish the arc almost instantaneously. This gas is highly effective for arc quenching and offers good dielectric strength. Well, SF₆ switches have become compact and reliable and are frequently used in sealed environments, for example, in ring main units or gas-insulated switchgear.

iii) Vacuum Load Break Switch

The difference in this type of switch is that the arc is broken in a vacuum chamber. Since there is no air or gas, the arc is extinguished instantly and cleanly. And, vacuum switches are exposed to systems that demand high reliability, and therefore, have long life and low maintenance.

iv) Manual and Motorised Load Break Switches

A manual switch has to be turned on and off by hand. This makes it simple to implement standard procedures. A motorised switch is easier and safer to use since it can be driven remotely, like in difficult and dangerous places, high voltage or high-altitude locations.

Each load break switch has unique advantages. By comprehending the fundamentals, a decision can be made in relation to the one that would best suit the electrical system in terms of safety, costs, placement, and control preference.

5) Where are Load Break Switches typically used?

Load break switches are used in most locations that require electrical control or power to be turned off safely. They are best used in medium and medium voltage systems, and their safe and reliable nature is trusted in many places. Here are some of the areas most associated with their use.

• Electrical Substations

Load break switches are installed in substations, which are one of the main areas. They assist in regulating the control of electric power to be used in high-voltage transmission lines and lower-voltage distribution lines. Apart from this, they also facilitate easy circuit isolation for maintenance or fault clearing.

• Industrial Plants

With a large consumption of electric power, factories and large-scale production units also have load break switches installed for power management to accommodate an overwhelming number of machines and sections. They enhance the safety of systems by providing for quick shutdowns in the case of emergencies.

• Commercial Buildings

In places such as shopping malls, offices, and even hospitals, these switches make sure that electricity is divided properly and can be switched off whenever necessary.

• Pole-Mounted Systems

Load break switches are often used in utility pole-mounted systems. These are important for utility companies because they manage electricity in a larger area. These systems are made to handle harsh environmental conditions such as extreme weather and are dependable in outdoor settings.

• Renewable Energy Systems

Load break switches are used in solar and wind power systems as well. They serve to separate components of the system for repairs or during periods of low production.

• Ring Main Units (RMUs)

In metropolitan power systems, load break switches are mounted in the RMUs for compact and dependable power distribution, especially in underground systems.

If there is a need to switch off power safely in any area, a load break switch will surely be there to do the task.

6) FKW18-33KV Outdoor Medium Voltage Air Load Break Switch

The FKW18-33kV is an outdoor air-insulated load break switch designed for use in three-phase AC power networks. It is compatible with nominal voltages of 40.5 kV, working at 50 Hz frequency. It represents a synthesis of local engineering experience with contemporary international practices.

The construction is divided into three principal parts: an isolation/opening blade, an arc-extinguishing chamber, and an operating mechanism.

• Key Technical Specs

• Rated voltage: 140.5 kV
• Rated frequency: 50 Hz
• Rated current (active and closed-loop breaking): 800 A
• Short-time withstand current: 20 kA for 4 s
• Peak breaking current: 50 kA
• Mechanical life: ~2,000 switching cycles
• Simultaneous three-phase open/close time: ≤ 15 ms

• Environmental & Installation Conditions

• It withstands harsh temperatures, making it suitable for outdoor use:
• Altitude: up to 3,000 m
• Temperature: -25 °C to +40 °C with daily variation ≤ 32 K
• Wind pressure tolerance: up to 700 Pa (~ 34 m/s)
• Pollution level: Class IV
• Seismic rating: up to 8 magnitude
• Permissible icing: up to 10 mm

• Features & Benefits

• Uses compressed air for arc quenching, allowing effective control and rapid interruption of arcs.
• Reduced upkeep required from maintenance is due to low part count and construction simplicity.
• Reliability and quality grading to international standards are strong for the insulation.
• With stable performance and longevity, reliability makes this suited for installation on poles or in switchgear.

7) FAQ

1. How should I select an appropriate Load Break Switch?

Consider the system voltage, current rating, environmental conditions, operation type (manual or motorised), insulation method, and indoor or outdoor use.

2. What is a medium‑voltage outdoor Load Break Switch?

This type of switch safely interrupts or isolates medium-voltage power (1kV–36kV) while being exposed to the elements. It is constructed to survive severe weather, heavy loads, and switching arc control.

3. Why is SF₆ gas used as an arc extinguishing medium?

SF₆ gas is especially effective in compact, sealed switchgear or high-voltage equipment. It cools and separates the arc quickly while offering substantial insulation, and safely interrupts the current flow.

8) Conclusion

Alright! So, a load break switch is a modern, intelligent, and economical device for controlling power in medium-voltage systems. It offers dependable and safe switching for industrial plants, utility poles, and commercial facilities. You can select from three available types—air, vacuum, and SF₆—to best suit your systems.

To be honest, a good example of durability and performance is Delixi Electric’s FKW18‑33 kV model. Choosing the appropriate load break switch helps enhance the seamless operation of your systems while maintaining safety and efficiency. You can contact Delixi Electric right now!