Surge Circuit Breaker, also known as SCB, is a new type of product used to replace traditional dedicated circuit breakers or fuses. It is specially designed for surge current protection, addressing the mismatch issues between surge protective devices and traditional circuit breakers.

The traditional approach places a fuse or circuit breaker in series before the lightning protection device, but this method has several mismatch issues:
When the performance of the lightning protector degrades or overvoltage occurs, it cannot break the circuit quickly
When the lightning protector short circuits to the ground, traditional fuses or circuit breakers cannot break the circuit quickly, which may lead to the failure of the lightning protector.
When lightning occurs, fuses or circuit breakers cannot withstand lightning currents
Traditional distribution elements like fuses are designed for conventional circuits and are not suitable for high-energy lightning currents, which can lead to tripping or damage.
High Up values cannot effectively protect equipment
Traditional circuit breakers cannot provide good protection for high Up (voltage rise) values.
Inability to break quickly, leading to equipment damage
Traditional circuit breakers installed in transformer power supplies cannot break quickly during short circuits, which may lead to equipment damage.
Surge circuit breaker as a new type of surge protection device can effectively solve the above problems, making it particularly suitable for modern electrical equipment environments demanding higher surge protection.
Installing the Surge Circuit Breaker before the SPD surge protection device can solve several key issues:
When the performance of the lightning protector degrades or the distribution line experiences overvoltage, SCB can break quickly to prevent the lightning protector from catching fire, with a breaking current of less than 3A.
When lightning current passes through, the SCB connected in series before the SPD can remain stable under lightning currents up to 100kA, ensuring the SPD works normally.
SCB’s breaking capacity far exceeds traditional fuses, reaching up to 100kA, effectively reducing the harm caused by surges in the circuit.
Surge Circuit Breaker is an external isolation switch dedicated for SPD, developed according to IEC430.3-61643-4 section 43. Its main role is to take appropriate overcurrent protection measures before circuit danger occurs. It can respond quickly to ensure the circuit is cut off promptly during surges or overvoltages, avoiding equipment damage or fire accidents, solving the protection blind spot problem of currently widely used fuses and circuit breakers as external isolation switches.
Surge Circuit Breaker is particularly suitable for environments requiring high-efficiency, reliable surge protection, including but not limited to:
Industrial and residential buildings
Power equipment
Communication facilities
Road traffic systems
Petrochemical industry
SCB is an ideal supporting device for SPD, ensuring the safe operation of electronic equipment in the face of surges or lightning, effectively extending the life of the equipment and reducing maintenance costs.
Do Surge Protectors Stop Electrical Fires?May 14, 2025Surge protectors (SPDs) can effectively reduce the risk of electrical fires caused by surges when designed, installed and maintained in accordance with international standards (such as the IEC 61643 s...view
Harm of lightning to DCS system of nuclear power plant and key points of lightning protection designJuly 8, 2022Lightning is a kind of meteorological disaster that often occurs in most areas of our country. It has the characteristics of strong suddenness and great harm, and often brings very serious threats to ...view
How Does A Surge Protection Device Work?August 30, 20211. Learn what is a power surge before undersanding a surge protection deviceFirstly, you need to understand what a power surge is before understanding how a surge protection device works. When the vol...view
Will a surge protector still work after a power failure? –Comprehensive Technical AnalysisApril 27, 2025Systematic maintenance ensures SPD reliability post-power failure.view
Integrated Lightning Protection Solution: Surge Protector for CCTV CameraJune 26, 2024CCTV video surveillance systems can be used for CCTV video surveillance systems. To ensure that the CCTV video surveillance system can operate continuously and stably, it is essential to integrate lig...view
What Are the Classification Protection of Lightning Protection System?January 10, 20221. Type 1 lightning protectionThe aim is to prevent voltage surge from being directly conducted from LPZ0 to LPZ1 and limit the voltage surge varying from tens of thousands of volts to hundreds of tho...view