LSP provides a complete Type 1+2 DC Surge Protection Device product portfolio designed for low-voltage DC systems (48V / 75V DC), serving critical infrastructure including telecom base stations, industrial automation, data centers, battery energy storage systems, EV charging stations, and security systems.
These surge protectors feature combined Type 1 (direct lightning protection, 10/350µs Iimp) and Type 2 (induced surge protection, 8/20µs Imax) capabilities, delivering comprehensive surge protection solutions for DC circuits.
Products strictly comply with IEC/EN 61643-41 standard, covering FLP-DC (standard type), FLP7-DC (high-current type with Imax 70kA), and FLP25-DC (heavy-duty type with Iimp 25kA) series to adapt to different lightning frequency and exposure scenarios.
Modular pluggable design supports quick replacement, remote signaling terminals provide real-time status monitoring, and arc prevention baffles are optimized for DC systems without zero-crossing, ensuring long-term reliable equipment operation.
Type 1+2 / Class I+II
10/350 µs & 8/20 µs
48V / 75V DC Systems
For typical applications such as telecom base stations and PLC control cabinets
IEC / EN 61643-41
Compliant with 2025 edition low-voltage DC SPD standard.
Type 1+2 DC Surge Protection Device is designed for 48V / 75V low-voltage DC systems, providing direct lightning current protection (10/350 µs) and induced surge suppression (8/20 µs). DC circuits have no zero-crossing point, requiring dedicated SPDs. The device undergoes type testing per IEC/EN 61643-41:2025, adopts open circuit failure mode (OCM), suitable for telecom base stations, industrial automation, and security systems.
The device consists of metal oxide varistor (MOV), thermal protection and disconnection mechanism, status indication and remote signaling terminal, arc prevention baffles, open circuit failure mode (OCM), and touch protection design. The module is optimized for DC systems without zero-crossing point, designed per IEC/EN 61643-41.
MOV serves as voltage-limiting protection element, conducting and discharging current after surge threshold is reached, returning to high impedance after voltage recovery. FLP-DC series use high-energy MOVs, meeting Type 1+2 combined protection requirements.
Status indication window displays device operation status in real time, green indicates normal, red indicates failure. Remote signaling terminal transmits status to monitoring system, triggering alarms on fault, supporting quick maintenance response.
The device adopts open circuit failure mode, disconnecting the circuit after MOV aging while system continues operation. DC systems have no zero-crossing point, short circuit failure (SCM) causes sustained arc and fire risk, OCM is the only allowed natural failure mode.
Thermal protection mechanism monitors MOV temperature, disconnecting circuit when overheating to prevent housing melting or spontaneous combustion. DC systems have no zero-crossing point, thermal protection is key mechanism preventing continuous arc-induced fire.
Arc prevention baffles at DC input terminals increase creepage distance, preventing arc propagation. DC arcs are difficult to self-extinguish, must be forcibly extinguished through physical isolation, avoiding continuous arc-induced fire.
Recessed line inlets and protected screw structures prevent operator contact with live parts. Housing material PA6+GF30% passes glow wire test, with no spontaneous combustion events recorded during operation.
Type 1+2 DC Surge Protection Device provides combined protection for direct lightning (10/350 µs) and induced surges (8/20 µs). MOV limits voltage and returns to high-impedance automatically. Compliant with IEC/EN 61643-41:2025, suitable for 48V/75V DC telecom, industrial automation, security, and data center systems.
Type 1+2 DC Surge Protection Device integrates Type 1 direct lightning protection and Type 2 induced surge protection in a single unit, using 10/350 µs waveform to verify Iimp and 8/20 µs waveform to verify In and Imax, covering full-level protection from direct lightning to switching surges.
Tested per IEC/EN 61643-41:2025, suitable for 48V / 75V DC telecom base stations, industrial automation, security systems, and data center infrastructure. DC circuits have no zero-crossing, making arc self-extinguishing difficult. The device uses open circuit failure mode (OCM) to ensure continued system operation after failure, avoiding short-circuit fire risk.
Metal oxide varistors (MOV) limit residual voltage to equipment withstand range, returning to high-impedance automatically after surge discharge, providing continuous downstream protection. The device cannot replace AC protectors, must match DC system voltage characteristics, and supports TN, TT, IT DC earthing systems.
FLP-DC series offers three Iimp ratings, covering applications from general telecom facilities to telecom operator infrastructure. Tested per IEC/EN 61643-41:2025, devices use MOV voltage-limiting elements and open circuit failure mode, ensuring surge protection safety for 48V / 75V DC systems.
Uc (Maximum Continuous Operating Voltage)
Uc indicates maximum continuous operating voltage, corresponding to system rated voltage. 48V systems use Uc 65Vdc, 75V systems use Uc 85Vdc, maintaining insulation during float voltage superposition. All three series share same Uc specifications, selected by system voltage.
Iimp (Impulse Discharge Current)
10/350 µs waveform verifies Iimp, reflecting direct lightning current capacity. FLP-DC series Iimp is 4kA, FLP7-DC series Iimp is 7kA, FLP25-DC series Iimp is 25kA. Select Iimp rating based on lightning exposure and protection level.
Imax (Maximum Discharge Current)
8/20 µs waveform verifies Imax, reflecting single-surge withstand capacity. FLP-DC series Imax is 30kA–40kA, FLP7-DC series Imax is 70kA, FLP25-DC series Imax is 100kA. Higher Imax provides greater discharge margin.
Up (Voltage Protection Level)
Up indicates device residual voltage level, reflecting equipment withstand matching. 48V systems control Up at 0.3kV–0.5kV, below equipment insulation withstand. All three series offer similar Up values, verified against equipment withstand.
| Parameter | FLP-DC Basic | FLP7-DC High-Current | FLP25-DC Heavy-Duty |
| Iimp (10/350 µs) | 4 kA | 7 kA | 25 kA |
| Imax (8/20 µs) | 30–40 kA | 70 kA | 100 kA |
| Up | 0.3–0.5 kV | 0.3–0.5 kV | 0.3–0.5 kV |
| Uc | 65/85 Vdc | 65/85 Vdc | 65/85 Vdc |
| Structure | Pluggable Module | Pluggable Module | Monoblock |
| Application | Telecom, Industrial Control | Outdoor Base Stations, High-Exposure Areas | Telecom Operator Infrastructure |
Type 1+2 DC SPD uses metal oxide varistors (MOV) as protection elements. MOV presents high-impedance state during normal operation, conducts surge current when surges arrive. The device protects against both direct lightning current and induced surges, controlling residual voltage within safe range. DC circuits have no zero-crossing, making arc self-extinguishing difficult. The device uses open circuit failure mode to ensure system safety.
MOV Voltage-Limiting Element Working Principle
MOV presents very high resistance during normal operation, acting like an insulator, not affecting system operation. When surge voltage exceeds MOV triggering voltage, MOV resistance drops rapidly, conducting surge current to ground terminal. After surge discharge, MOV automatically returns to high-impedance state, DC system resumes normal operation.
Surge Protection Mechanism
Direct lightning current has high energy but low frequency, MOV discharges it to earth through high-current path. Induced surges have lower energy but high frequency, MOV rapidly clamps voltage to safe level. The device is tested with both waveforms, ensuring reliable equipment protection in various surge scenarios.
DC Arc Protection Design
DC circuit current flows continuously in one direction, formed arcs are difficult to self-extinguish, potentially causing fire. Device sets arc-prevention baffles at DC input terminals, increasing distance between live parts, preventing arc initiation from short circuits. This design meets DC system safety requirements, protecting personnel and equipment.
Open Circuit Failure Mode
The device uses open circuit failure mode, automatically disconnecting when MOV ages or fails, system continues operation. DC systems do not permit short-circuit failure, as continuous short circuit causes sustained arcs and fire. Remote signaling terminal sends alarm during failure, prompting maintenance personnel to replace module.
Differences from AC SPD
AC systems have voltage zero-crossing, arcs naturally extinguish. DC systems have no zero-crossing, once formed arcs persist, requiring dedicated arc-prevention design. AC SPD permits short-circuit failure, DC SPD must use open circuit failure mode, the two cannot be interchanged.
Type 1 testing uses 10/350 µs waveform to simulate direct lightning current, verifying device capability to withstand high-energy surges. Type 2 testing uses 8/20 µs waveform to simulate induced surges, verifying device rapid response and repetitive discharge capability. Two waveforms correspond to Iimp, In, Imax parameters, comprehensively evaluating SPD protection performance.
Type 1 Waveform 10/350 µs Characteristics
10/350 µs waveform has 10 µs front time and 350 µs half-peak time, with long energy duration. This waveform simulates direct lightning current, single pulse carrying energy far exceeding induced surges. Device validates current capacity under this waveform through Iimp testing, ensuring effective large current discharge during direct lightning intrusion.
Type 2 Waveform 8/20 µs Characteristics
8/20 µs waveform has 8 µs front time and 20 µs half-peak time, fast rise time but short duration. This waveform simulates induced lightning and switching surges, occurring at higher frequency than direct lightning. Device validates rapid response capability under this waveform through In and Imax testing, ensuring reliable protection in frequent surge environments.
Waveform Energy Comparison
10/350 µs waveform single pulse energy is approximately 100 times higher than 8/20 µs waveform. Direct lightning current energy is concentrated, requiring SPD with high current capacity and thermal stability. Induced surge energy is dispersed, requiring SPD with rapid response and repetitive discharge capability. Type 1+2 SPD passes both waveform tests, covering surge threats of different energy levels.
Type 1+2 DC SPD adopts common mode protection paths, installing protection elements between positive-to-ground and negative-to-ground. DC systems have no zero-crossing, arcs difficult to self-extinguish, grounding design must ensure rapid surge energy discharge. Device uses equipotential bonding and short-path grounding, reducing grounding impedance, improving protection effectiveness.
Common Mode Protection Paths
Common mode paths are (DC+)-PE and (DC-)-PE, suppressing positive-to-ground surges and negative-to-ground surges respectively. Positive and negative poles protect independently, covering all line-to-ground fault scenarios, ensuring comprehensive DC system protection. Common mode protection applies to TN, TT, IT DC earthing systems, being the primary protection method for low-voltage DC systems.
Differential Mode Protection Paths
Differential mode paths are line-to-line, such as (DC+)-(DC-), suppressing inter-pole surges. This product focuses on common mode protection, does not provide differential mode protection function. If differential mode protection is needed, additional differential mode SPD should be configured at equipment front-end, achieving full-mode protection. Differential mode protection typically applies to special scenarios, such as long-distance cable transmission systems.
Grounding Requirements
SPD grounding conductor must connect to main equipotential bonding system, ensuring grounding resistance meets standard requirements. Grounding path should be short and direct, avoiding loop inductance affecting surge discharge effectiveness. Grounding conductor cross-section must meet current carrying capacity, ensuring conductor does not heat or damage during large current surges.
Equipotential Bonding
Equipotential bonding connects SPD grounding terminal, equipment enclosure, metal structures to same reference potential. This connection reduces potential difference, preventing ground potential rise from causing equipment damage. DC system equipotential bonding must consider DC polarity, ensuring positive and negative pole grounding paths are independent and reliable.
Type 1+2 DC Surge Protection Device is installed at the boundary between LPZ 0A/0B and LPZ 1, integrating direct lightning current dissipation and voltage limitation functions. The device simplifies multi-stage surge protection solutions, supporting coordinated protection with downstream LPZ 2 equipment. DC systems have no zero-crossing, device uses open circuit failure mode and arc-prevention design, ensuring continued system operation.
Type 1+2 DC SPD integrates direct lightning protection and induced surge protection in a single module, providing coordinated protection functions. The device covers 10/350 µs and 8/20 µs waveforms, meeting full-level surge protection requirements of DC systems. Single-module design reduces installation space, simplifies system configuration.
The device uses open circuit failure mode, automatically disconnecting when MOV ages or fails, DC system continues operation. DC systems do not permit short-circuit failure, as continuous short circuit causes arc and fire risks. Remote signaling terminal triggers alarm during failure, prompting maintenance personnel to replace module.
Key conductive components of the device are mechanically reinforced, ensuring stable current paths under high-energy impulse currents. Terminals approximately 0.8 mm thick and 8 mm wide, low contact resistance, reducing thermal stress. Reinforced design ensures structural integrity, extending device service life.
The device undergoes standardized testing to verify electrical, thermal, and environmental performance. Testing contents include 10/350 µs lightning impulses, 8/20 µs surge currents, thermal stability, salt spray exposure, and current impulse cycling. Comprehensive verification ensures long-term reliable operation in DC systems.
Type 1+2 DC Surge Protection Device is applied in low-voltage DC systems (48V / 75V), installed at the boundary between LPZ 0A/0B and LPZ 1. The device is suitable for telecommunications, data centers, industrial automation, energy storage, security, and EV charging, protecting DC distribution systems from lightning and surge impacts.
Type 1+2 DC Surge Protection Device undergoes standardized testing to verify electrical performance, thermal stability, and environmental adaptability. The device complies with IEC 61643-41:2025 and IEC 61643-11 requirements, covering lightning impulse, overstress, temporary overvoltage, salt spray corrosion, and thermal cycling scenarios.
LSP organizes production according to ISO 9001 quality management system, Type 1+2 DC Surge Protection Device manufacturing process includes raw material inspection, component assembly, electrical testing, environmental verification, and finished product inspection. Production process executes standardized control, ensuring product complies with IEC 61643-41:2025 standard requirements. Company has served 1,200+ customers globally, supplying telecom, energy storage, industrial DC and other fields.
LSP provides end-to-end OEM/ODM solutions for Type 1+2 DC Surge Protection Device, covering manufacturing, R&D, production, and warranty. Following ISO 9001 quality management system, serving over 1,200 global enterprises.
Production follows ISO 9001 standards with full-process quality control ensuring batch delivery consistency. Products certified by TUV, CB, and CE, providing complete documents for project submission.
5-year warranty, including 7-day return and exchange. Full-lifecycle quality tracking ensures production process traceability, guaranteeing long-term reliable operation.
20-year experienced team offers selection guidance, design optimization, and technical solutions. Modular design supports on-demand configuration of housing, protection levels, and monitoring interfaces, covering 48V to 75V voltages.
Supports 1-pole to multi-pole flexible configuration, customizable system voltage, protection current, monitoring interfaces, and housing. Modular design facilitates maintenance and component replacement, reducing O&M costs.
Standard configuration 15 days, customized configuration 30 days. Flexible production scheduling and globalized supply chain support ensure on-time project completion.
Type 1+2 DC Surge Protection Device optimizes product performance and structural design based on actual engineering data, enhancing system reliability through verified practices. The device combines low-voltage DC system characteristics, implementing improvements in safety design, component quality, and process optimization.
Type 1+2 DC SPD installs in low-voltage DC system main distribution boards, fixed via DIN rail (35mm). The device uses parallel connection between DC lines and protective earth (PE). Power-off operation required before installation, use insulated tools, and confirm correct line polarity. After installation, check connection tightness, perform insulation resistance and continuity tests, confirm proper function before energizing. For detailed connection specifications, fuse selection, grounding requirements, and remote monitoring configuration, please refer to the product installation manual.
Parallel Connection: Install the Type 1+2 DC Surge Protection Device in parallel at the main DC distribution point.
Backup Protection: Use a dedicated DC circuit breaker or fuse in front of the Type 1+2 DC SPD for enhanced safety.
DIN-Rail Mounting: Compact design allows easy installation of Type 1+2 DC Surge Protectors on standard DIN rails.
Waveform Handling: Designed to withstand lightning current impulses (10/350 μs) and switching surges (8/20 μs).
Real-Time Monitoring: Remote terminals on Type 1+2 DC Surge Protective Devices enable continuous status supervision.
Fault Alerts: Provide early warning signals in case of SPD failure or end-of-life condition.
System Reliability: Support quick maintenance response, ensuring uninterrupted protection for low-voltage DC systems.
Type 1+2 DC SPD operates in global projects across telecommunications, data centers, industry, energy storage, security, and EV charging. The following feedback comes from on-site engineers and project managers, including specific operational data and maintenance records.
A Type 1+2 DC surge protection device (SPD) combines the functions of Type 1 and Type 2 SPDs, providing fast, reliable protection against both high-energy surges and residual voltage spikes in low-voltage DC systems.
Type 1+2 DC SPDs respond within nanoseconds to transient overvoltages, limiting voltage spikes to safe levels and protecting sensitive DC equipment such as PLCs, batteries, and communication devices.
These SPDs are widely applied in:
Yes. Many Type 1+2 DC SPDs integrate arc-quenching structures and fast disconnection mechanisms to interrupt DC arcs immediately in the event of device failure, reducing fire risks and enhancing system safety.
Key specifications include:
Select Type 1+2 DC SPDs from reputable manufacturers with IEC-standard testing for DC systems. Proper installation, adherence to rated voltage/current, and routine inspection help maintain optimal surge protection performance. These measures ensure reliable protection against lightning and switching transients over the SPD’s service life.
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