What Kind of Damage can Lightning Cause?
Most electrical and electronic damage in both grid-tie and off-grid solar electric systems is NOT due to a direct hit. In fact, direct hits are rare. Most damage occurs from nearby hits, usually within a few hundred feet. A near-strike can induce thousands of volts onto the house and PV array wiring if not protected. In a ground hit, it can also spread out and travel into buried conductors, such as pipes and buried cables. Contrary to popular assumption, the panels themselves are not the biggest victim – inverters and controllers are. The frames and mounts on panels are usually grounded (sometimes more by accident than design), and that often diverts the lightning directly to ground, saving the panels. Also, the battery banks on most off-grid PV systems acts as a fairly good surge arrestor if you have good connections and a good ground – but it may take out the controller on it’s way. If the battery bank is not grounded, damage can be much more severe – it may then leap around all over trying to find a path to ground.
Lightning Surge Protection
