In lightning protection, the surge protection device in distribution boxes plays a crucial role. According to the principle of graded lightning protection, and based on the likelihood of a building being struck by lightning, it is necessary to deploy surge protector against lightning in stages to ensure the safety of the power system and electrical equipment.
Scope of Application
The main distribution box at the power supply system's entry point.
Purpose
Absorb high-energy surge currents and protect downstream circuits and equipment.
Installation Recommendations
Connect the three-phase wires A/B/C to the corresponding terminals of the surge protector.
The yellow-green ground wire should be connected to the distribution box's dedicated surge protection grounding terminal (note: not the power ground or protective earth).
Technical Requirements
Level 1 SPD box surge discharge current ≥ 12.5kA.
Maximum discharge capacity: ≥ 100kA per phase.
Voltage protection level: ≤ 2500V.
The Level 1 surge protection device is designed to withstand high-current surges from direct lightning strikes or induced lightning. It diverts most surge current to the earth. This device mainly protects the basic safety of the power system and provides a medium level of voltage limitation, but cannot fully protect sensitive equipment within the system.
Scope of Application
Distribution boxes supplying power to important or sensitive equipment.
Purpose
Further absorb the residual surge energy after Level 1 protection and enhance the ability to suppress transient overvoltages.
Installation Recommendations
Install the Level 2 surge protection device in the distribution equipment to focus on protecting sensitive equipment.
Technical Requirements
Maximum discharge capacity: ≥ 40kA per phase.
Voltage protection level: ≤ 2000V.
Level 2 protection mainly focuses on suppressing transient overvoltages and effectively absorbs the residual surge energy after Level 1 protection. This level of protection is usually sufficient for the normal operation of most electrical devices.
Scope of Application
Within the electrical equipment or at the terminal power supply.
Purpose
Completely eliminate the effects of micro transient overvoltages and protect precision electronic equipment.
Installation Recommendations
Install the Level 3 surge protection device inside the equipment or at the equipment's power supply input, especially for critical or sensitive electronic devices.
Technical Requirements
Maximum discharge capacity: 20kA per phase or lower.
Voltage protection level: ≤ 1800V.
Level 3 protection is the final barrier of the system, capable of fully eliminating any transient overvoltage that may occur, ensuring the long-term stable operation of sensitive equipment.
Terms and definitions of IEC 61643-11: LOW-VOLTAGE SURGE PROTECTIVE DEVICES （2/2）December 8, 2022the professional explanation of main terms of surge protective devicesviewThe Position of Installing Surge ProtectorMarch 23, 20221. Where to install surge protector？The position of the surge protector: the surge protector is an important component of the lightning protection project in a building, so the location of the surge prote...viewDo surge protectors work against lightning?April 27, 2025Although surge protectors cannot directly prevent lightning strikes, they can significantly reduce the damage caused by lightning strikes to electrical equipment and circuits. As a specially designed ...viewWhat Is a Surge Circuit Breaker?June 26, 2024Surge 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 th...viewInstallation Steps of The Surge Protection DeviceAugust 30, 2021Ⅰ. Tools of installing a surge protection deviceBefore installing the surge protection device, tools such as a flat-blade screwdriver, a pair of wire strippers, some pliers and electrical tape are ne...viewEco-Friendly Power: The Environmental Impact of SPD for Power SupplyJanuary 5, 2024In an era where environmental sustainability is a global priority, the deployment of Surge Protection Devices (SPDs) for power supply emerges as a crucial component in creating a greener and more resp...view
EN
jp 
ko 
fr 
de 
es 
it 
ru 
pt 
ar 
vi 
th 
ro 
bg 
nl 
