Surge Protective Device Description

Surge protective device Surge protector is a protective device designed to prevent electrical equipment from being damaged by transient voltage surges. It detects abnormal voltage spikes in the system and quickly diverts the excess energy to the ground wire, thereby preventing damage to sensitive devices from voltage surges.

Surge Protective Device Working Mechanism

Surge protectors operate in a high-impedance state during normal system conditions, ensuring uninterrupted circuit performance.However, when transient voltage surges occur—such as those caused by motor startups, load switching, or lightning-induced spikes—the protector instantaneously switches to a low-impedance path, safely channeling excess energy to ground and shielding sensitive equipment from damage.Once the surge subsides, the device automatically resets to its high-impedance state, resuming its silent vigilance against electrical disturbances.

Surge Protective Device Key Application Scenarios

Lightning protection: protect against surges caused by direct or inductive lightning.

Grid fluctuations: suppress overvoltages caused by grid switch operations, capacitor switching, etc.

Electronic equipment protection: protect precision instruments such as computers, communication equipment, and household appliances.

Industrial systems: ensure stable operation of key equipment such as PLCs, inverters, and sensors.

Surge Protective Device Standards and Regulations

Global Markets

   IEC/EN 61643-11, IEC/EN 61643-21, IEC/EN 61643-31, IEC/EN 61643-41, IEC/EN 61643-21, IEC 61643-311, IEC 61643-321, IEC 61643-331, IEC 61643-341.

North America (United States, Canada and Mexico)

United States:

   UL 1449, Standard for Surge Protective Devices (SPDs), edition 5 issued January 8, 2021

   UL 497B, Protectors for Data Communications and Fire-Alarm Circuits

Canada: CSA C22.2 NO. 269 Series of SPD Standards

Mexico: NOM-003-SCFI (NMX-J-515-ANCE)

Surge Protective Device Installation

• The power supply must be cut off before installation, and live operation is strictly prohibited;
• It is recommended to connect a fuse or circuit breaker in series at the front end of the module;
• Please connect according to the installation diagram during installation, where DC+ is the positive line, DC- is the negative line, and PE is the ground line. Do not connect them wrongly. After the installation is completed, close the circuit breaker (fuse) switch and check whether the working status is normal;
• After the installation is completed, place the module correctly and check whether the module is working properly;
• During the use of the module, the fault display window status should be regularly checked and checked. When the fault display window is red or the remote  signal terminal outputs an alarm signal, it means that the module has a fault and should be repaired or replaced in time;