Since 2010, LSP has specialized in high-performance DC surge protective devices (SPDs) that safeguard systems from transient overvoltages caused by lightning and switching operations. Certified by ISO9001, TUV, CB, and CE, LSP uses premium components such as LKD MOVs, Vactech GDTs to ensure durability and long-term reliability across solar PV, energy storage, and e-mobility applications.
Engineered in full compliance with IEC/EN 61643-31, LSP’s DC SPDs, featuring Type 1+2 and Type 2 DC Surge Protectors, offer a robust modular design compatible with 3+1 and 4+0 configurations, delivering stable protection in demanding environments. Backed by a 5-year warranty and responsive technical support, LSP provides dependable surge protection that keeps every DC system operating safely, efficiently, and without interruption.
A PV string is not “an AC circuit with a different voltage label.” Three things — no zero-crossing, 1,000–1,500V continuous stress, and long outdoor cable runs — make AC SPDs unsuitable for PV systems.
Three reasons:
No zero-crossing — MOV failure becomes a fire AC passes through zero 100 times per second, so any arc self-extinguishes. DC has no zero-crossing — once a MOV conducts, it keeps conducting until it overheats or ignites.
1,000–1,500V continuous stress A PV string can reach 1,500V Voc at low temperatures. An AC SPD labeled 1,000V placed on a 1,500V system will slowly age and fail within months.
100m+ outdoor cable runs — an antenna for induced lightning Roof-to-combiner-box runs often exceed 100m. A strike 1 km away can induce several kV on those long cables — the most common surge source in PV systems.
Which standard applies to DC surge protection?
| Application | Standard | Scope |
| AC systems (230V / 400V) | IEC 61643-11 | Generic low-voltage AC SPDs |
| PV / Solar (≤ 1,500V DC) | IEC 61643-31 | Photovoltaic DC-side dedicated; LSP’s full PV SPD line follows this standard |
| Low-voltage DC (non-PV, 24 / 48 / 110V) | IEC 61643-41:2025 | Published 2025-05-23, 1st edition, TC 37/SC 37A |
What happens when you fit the wrong SPD:
AC SPD on a DC system — once the MOV conducts, no zero-crossing to extinguish the arc; Sustained heat leads to fire or sudden failure.
Low-voltage DC Surge Protector on a PV system — voltage exceeds the Ucpv; The MOV slowly ages and fails within months.
Type 2 at the rooftop direct-strike entry — no Iimp capability; A direct strike burns through and the inverter is still damaged.
In one line: the only correct standard for PV systems is IEC 61643-31. Every LSP PV SPD is designed, manufactured, and tested to that standard.
Step 1: Read Voc, select identifier voltage
Step 2: Check the installation point, decide Type
Step 3: Confirm pole count, finalize the model
After these three steps, you can usually jump straight to S2 to pick the specific model. If you get stuck on any step, use the “Send Your System Parameters” block (A3) and we’ll match it for you.
Decision flow — ask yourself three questions:
Is the SPD installation point within 10m of a building down conductor?
Is the SPD on the rooftop, on the ground, or in an outdoor enclosure?
Does the site have an external lightning rod or air-termination?
Any “yes” → select Type 1+2 (FLP). All “no” — and the SPD is indoors / inside an enclosure / downstream of another SPD → select Type 2 (SLP).
Key spec comparison:
Comparison | Type 1+2 (FLP) | Type 2 (SLP) |
Identifier Voltage (Voc) | 600 / 1,000 / 1,200 / 1,500V | 1,000 / 1,500 / 2,000V |
Iimp (10/350 μs, direct strike) | 6.25 kA | — |
Imax (8/20 μs, induced surge) | 40 kA | 40 kA |
In | 20 kA | 20 kA |
Up (residual voltage) | per model, see datasheet | per model, see datasheet |
Short-circuit current ISCPV | per model | per model |
Where it goes | Rooftop / outdoor / strike entry | Inside combiner box / inverter DC input |
Price range (reference) | ~ 1.5–2× of Type 2 | baseline |
What if you put Type 2 at the rooftop entry?
The rooftop is the most exposed to direct strikes. Direct-strike current has a 10/350 μs waveform with peaks of tens of kA — far beyond Type 2’s endurance. The Type 2 can be burned through, and the inverter is still damaged.
Internal Ucpv designed to IEC 61643-31
Internal Ucpv is worked out model by model by our engineering team and is not always a whole number.
Specific internal values are LSP engineering details and not disclosed in public materials.
This differs from the AC SPD’s Uc rule
What LSP does for you
Model | Type | Identifier Voltage (Voc) | Ucpv (Marked) | In | Imax | Iimp | Up | Max PV Short-circuit Current (ISC) |
FLP-PV600/S | 1+2 | 600V | 600V | 20 kA | 40 kA | 6.25 kA | ≤ 2.2 kV | 1,000A |
FLP-PV1000/S | 1+2 | 1,000V | 1,000V | 20 kA | 40 kA | 6.25 kA | ≤ 4.0 kV | 1,000A |
FLP-PV1000G/S | 1+2 | 1,000V | 1,000V | 20 kA | 40 kA | 6.25 kA | ≤ 4.0 kV | 1,000A |
FLP-PV1200G/S | 1+2 | 1,200V | 1,200V | 20 kA | 40 kA | 6.25 kA | ≤ 4.4 kV | 1,000A |
FLP-PV1500G/S | 1+2 | 1,500V | 1,500V | 20 kA | 40 kA | 6.25 kA | ≤ 5.2 kV | 1,000A |
SLP-PV1000/S | 2 | 1,000V | 1,000V | 20 kA | 40 kA | — | ≤ 4.0 kV | 1,000A |
SLP-PV1500/S | 2 | 1,500V | 1,500V | 20 kA | 40 kA | — | ≤ 5.2 kV | 1,000A |
SLP-PV2000/S | 2 | 2,000V | 2,000V | 20 kA | 40 kA | — | ≤ 6.5 kV | 1,000A |
Common mechanical & accessory specs (all models):
As leading SPD manufacturers, we offer comprehensive DC Surge Protection Solutions for reliable and versatile protection across diverse DC applications.
As one of the best surge protector brands, LSP ensures unmatched protection and reliability, safeguarding your electrical systems with superior performance.
Our patented safety core is engineered to overcome thermal runaway from DC arcs—the primary fire risk—achieving this quantifiable reduction in catastrophic thermal events compared to conventional mechanisms.
We specify a glass-fiber reinforced composite (PA6+GF30%) for its exceptional mechanical strength and thermal stability. Validated by rigorous glow-wire testing, this critical choice ensures the housing maintains its integrity and will never contribute to a fire.
Our DC SPD adopts a polarity-tolerant structure that prevents damage from reversed wiring, making installation faster, safer, and worry-free.
Our SPD's capability to protect against both direct lightning currents and switching surges is validated through rigorous testing to both 10/350 µs and 8/20 µs waveforms, ensuring comprehensive defense for your electrical systems.
Our SPD uses reinforced metal contacts (8 mm × 0.8 mm). This high-mass design significantly lowers resistance and heat buildup, mitigating the constant thermal stress of DC systems to ensure stable, long-term protection.
Our DC SPD employs fully sealed MOVs proven stable under 85 °C / 85% RH testing, resisting moisture and dust for durable outdoor performance.
LSP’s DC surge protectors deliver robust, application-specific protection across a variety of critical sectors — including solar PV systems, energy storage systems, wind turbines, electric vehicle charging stations (e-mobility), telecommunications & data centers, industrial DC power systems, LED lighting, control systems, and process utilities (e.g., water treatment).
LSP’s DC Surge Protective Devices (SPDs) deliver certified DC surge protection across a wide range of DC applications. Each device is rigorously tested to IEC/EN 61643-31 standards, ensuring reliable, long-term safety and performance. Designed for versatile integration, our SPDs provide superior protection against lightning and switching surges in diverse DC power systems.
Core components: named brands for MOV and GDT Varistors (MOV) come from LKD, gas discharge tubes (GDT) from Vactech. These two do the actual work inside the SPD, so we don’t swap suppliers on them to shave cost.
Metal lead pins: 0.8 mm thick, 8 mm wide Pins are built at 0.8 mm thick and 8 mm wide, and withstand high electrical potential without breaking.
Arc suppression and fire prevention: low-temperature trip + baffles at the line end An optimized soldering process and a low-temperature trip mechanism keep arc and fire risk down. DC has no zero-crossing, so once an MOV conducts, only a mechanical action can open the circuit — the trip mechanism is the last gate on that path. Elevated baffles at the incoming line end solve arcing caused by inadequate creepage distance and electrical clearance.
Casing and copper parts: flame-retardant, and corrosion-resistant for sea freight The casing is flame-retardant plastic; current-carrying parts use brass, red copper, and phosphor bronze, with enough corrosion resistance for heat, humidity, and long ocean transit. It arrives ready to install.
Structural improvement: inverted-V base + sunk line inlet The base was redesigned with an inverted-V profile — more stable overall, and it helps direct surge energy. The line inlet is sunk and a circular protrusion sits above the screw hole, so screw depth stays sufficient and clear of the plastic surface. Neither is a one-off change — every revision moves something.
A DC Surge Protector is a device installed in a DC circuit. When a transient overvoltage from lightning or switching arrives, it can “short” the overvoltage to ground within milliseconds, protecting downstream equipment — inverters, combiner boxes, battery storage.
Torque the wiring terminals per spec.
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