A Load Break Switch (LBS) is a type of switch specifically designed to make or break electrical circuits under load conditions. It is equipped with mechanisms that allow for the interruption of electrical currents safely when the switch is operated, including during load currents. This capability is achieved by adding components that increase the operating speed of the switch and reduce or control the arc that forms when switching, allowing for safe disconnection or connection under load.

Disconnect switches can be modified with equipment to enable limited load switching capabilities. Common equipment like arcing horns, whips, and spring actuators are often used at lower voltages to enhance the switch’s performance.

These switches are typically used to de-energize or energize circuits that have some level of load, such as the magnetizing current of a transformer or line charging currents.

In higher voltage and current applications, an air switch can be modified with a series interrupter to increase the load-break capability of the switch, allowing it to switch load or fault currents safely.

Advantages of Load Break Switches

1. Cost-Effective: LBS is generally less expensive compared to a 2-pole circuit breaker structure.
2. Safer Operation: LBS provides enhanced safety, especially in applications involving high-voltage equipment.
3. Transformer Protection: Load break switches can be paired with HRC fuses for transformer protection, providing an extra layer of safety.
4. Easy to Operate: It is very simple to turn the supply on and off using a Load Break Switch.

Load Break Switches typically use a spring mechanism for switching on and off the supply. However, options with a vacuum circuit breaker are also available for more reliable performance, though this option tends to be more expensive. The choice between a spring mechanism and a vacuum circuit breaker depends on the user,s needs.

• Spring Mechanism with Fuse Protection: The LBS with a spring mechanism often comes with fuse protection, so if a fault occurs, the fuse needs to be replaced.
• Vacuum Circuit Breaker Option: If equipped with a vacuum circuit breaker, no fuse replacement is necessary, and the breaker can be reset by simply turning it back on.
• Load Break Switches are also equipped with an Earth Switch, which allows the switch to safely ground any residual charges that might remain after the switch is turned off.

 

Differences Between A load break switch is a device used to isolate and disconnect electrical currents in a circuit, while a circuit breaker is designed to interrupt the flow of current in the event of an overload or short circuit.

When comparing a Load Break Switch (LBS) with a Circuit Breaker (CB), there are two key parameters to consider:

1. Breaking Capacity: The ability to interrupt current flow during fault conditions.
2. Making Capacity: The ability to close a circuit and establish current flow, which includes handling inrush currents and faults that may occur at the moment the switch is closed.

• Circuit Breakers (CBs) are designed to handle both making and breaking capacities, which means they can make and break load currents and fault currents.
• Load Break Switches, on the other hand, are only designed to break load currents and can be closed onto a fault (i.e., they have a making rating), but cannot break a fault current.

This distinction means that Load Break Switches are primarily used for disconnecting or isolating healthy circuits under normal conditions, and are typically switched on when there is no load. In contrast, Circuit Breakers are capable of operating under fault conditions to clear faults and protect electrical equipment by making and breaking both load and fault currents.
Precautions should be taken when using LBS for long cables or lines with high capacitance (such as transformers), as the LBS has limitations in switching high charging currents or reactive loads. In these cases, a Circuit Breaker is usually recommended.

Summary

• Load Break Switches are used to disconnect and isolate healthy circuits under normal conditions, without the ability to handle fault currents. They are designed for safety and cost-efficiency but should only be switched on under no-load conditions.
• Circuit Breakers are designed to handle both making and breaking currents, including fault currents, and are used for fault clearing and protecting electrical equipment.GONGSHUN Electrical Co.,Ltd (electric-cn.com), CHNGS was established in 1990S, specializing in the manufacture, sales and service of high-voltage electrical products. 

GONGSHUN Electrical Co.,Ltd (electric-cn.com), CHNGS was established in 1990S, specializing in the manufacture, sales and service of high-voltage electrical products. 

Our technical expertise, comprehensive product portfolio and long-term rich experience are helping many customers in need to solve their power problems. We're happy to help at any time.  Whether you need application product advice or technical assistance, our global service team is committed to providing you with the right support. For more technical information about load break switch, feel free to contact us, send an email to gongshun@electric-cn.com