Surge Protection for Solar PV Systems: A Practical Installation Guide

Photovoltaic systems cover large outdoor areas and connect to long cable runs, making them especially vulnerable to lightning-induced surges. Without proper protection, a single strike can destroy inverters and panels.

Protect both the DC and AC sides

Install a DC surge protective device at the inverter input (combiner box) and an AC SPD at the inverter output or main distribution board. Both are required for complete protection.

Type 1 vs Type 2 SPDs for solar

• Type 1 – for installations with external lightning protection, handling direct strike currents.
• Type 2 – the standard choice for protection against indirect and switching surges.

Grounding and equipotential bonding

An SPD is only effective with a low-impedance earth. Bond the array frames, mounting rails and inverter to the same grounding system, keeping SPD leads as short as possible.

Walax solution

Walax supplies DC SPDs rated for 600V and 1000V PV systems plus AC SPDs from 20kA to 80kA, giving installers a complete surge protection package for solar projects.