A Compact Surge Protection Device For Residential Setups

Key takeaways: 

• PV Inline’s compact and flexible design allows installation in cable ducts, on walls, or behind modules, ideal for limited rooftop space 

• The SPD provides strong surge protection up to 40,000 A and supports solar systems up to 1,100 V DC, suitable for most residential and commercial setups 

• It complies with EU and German regulations, ensuring mandatory surge protection for residential PV installations

Weidmüller, a German family-owned business, supplies a wide range of products, including surge protection devices (SPD), combiner boxes, hand tools, connectors, printing and marking systems, among others, required between modules and inverters during installation. The company won The smarter E Award for its PV surge protection device, specifically designed for residential small-scale installations.

SPD plays an important role in protecting PV installations from overvoltage, which can be caused by grid-related surges or lightning strikes, even those occurring several kilometers away from the installation site. SPD is typically an integral part of a combiner box, where all the module strings are connected. 

For residential PV installations, the use of an SPD may not be mandatory depending on local regulations. However, if an SPD is required, “it must be near to the PV panels or at least before the string cables enter the building,” says Weidmüller’s Project Manager, Jan Marrenbach. This can be challenging due to limited space on rooftop installations. With strict regulations in the European Union, and particularly in Germany, installing an SPD is mandatory for all residential systems. 

Weidmüller has developed a compact SPD for residential installations, called PV Inline. According to the company, this is the smallest design on the market. PV Inline can be installed in a cable duct, between cable ducts, fixed on a wall, or mounted behind the module. The product is available in 2 variants, 1 and 2 MPP, indicating the maximum power points. Both variants feature protection class II, providing protection against surges caused by indirect lightning and grid switching operations. 

According to the product datasheet, PV Inline is designed to protect the DC side of a solar system from large electrical surges up to 40,000 A, caused by sudden events like lightning or power spikes. It is suitable for solar systems of up to 1,100 V DC, covering most commercial and residential installations. The SPD can handle a short-circuit current of 6,000 A. The product is certified to IEC and EN standards and is suitable for both type I and type II surge protection.