PV Surge Protection Device

A PV surge protective device (SPD) is a DC surge protector specifically designed for photovoltaic systems. Unlike standard DC SPDs, PV SPDs are rated and certified under IEC 61643-31 — the standard covering surge protective devices connected to photovoltaic power generation systems. They protect solar panels, string inverters, combiner boxes, and DC cabling from transient overvoltages caused by lightning strikes and switching operations, preventing costly equipment failure and system downtime.

PV SPDs should be installed at two key points in the DC circuit. The first is at the output of the PV combiner box or string junction box, protecting the DC cabling runs between the solar array and the inverter. The second is at the DC input terminals of the string inverter, providing a final layer of protection directly upstream of the inverter electronics. For systems with an external lightning protection system (LPS), a Type 1+2 PV SPD is required at the combiner box. For systems without LPS, a Type 2 PV SPD is sufficient.

The maximum continuous operating voltage (Ucpv) of the SPD must be equal to or greater than the maximum open-circuit voltage of the PV string under standard test conditions (Uocstc). For a 1000V DC system, select Ucpv ≥ 1000V. For 1500V DC utility-scale systems, select Ucpv ≥ 1500V. Thor’s PV SPD range offers Ucpv options of 600V, 720V, 800V, 1000V, 1200V, and 1500V DC to match the most common string inverter configurations.

The answer depends on whether your installation has an external lightning protection system (LPS). If an LPS is present — meaning there are lightning rods and down conductors on or near the structure — IEC 62305 requires a Type 1+2 PV SPD at the DC input, as direct lightning currents may be conducted into the PV array. If no LPS is present, a Type 2 PV SPD is the standard requirement. For most commercial and utility-scale ground-mount projects, Type 1+2 is the safer and more common specification.

Yes. Thor’s Type 1+2 PV SPD range includes models with Ucpv ratings up to 1500V DC, covering the high-voltage string configurations used in utility-scale solar farms and large commercial rooftop installations. The TRS3-C40 series is available in Ucpv 1200V and 1500V variants. Contact our team for datasheet and application guidance.

Can I request a free sample of your PV SPD before ordering?
Yes. Free samples are available for qualified solar project developers, EPC contractors, and distributors. Please submit your request via the contact form with your company details, project voltage, and inverter type. Samples are typically dispatched within 3 business days.

Yes. Thor SPD provides OEM and ODM manufacturing for PV SPDs, including custom Ucpv ratings, branding, and packaging. We work with solar EPC contractors, inverter manufacturers, and electrical distributors globally. Minimum order quantities and pricing are available upon request.