Solar Lightning Arrestors
Lightning is a common cause of failure in off-grid solar systems. Most often damage does not occur as a result of a direct hit, but from nearby hits. A nearby hit can induce thousands of volts into a solar system if not protected. A ground hit can also spread out and travel into buried conductors, such as buried cables and pipes. Grounding is the most fundamental technique for protection against lightening damage. A lightning surge cannot be stopped, but a direct path to ground that bypasses equipment can be accomplished. In addition to grounding, specialized surge protection devices are recommended for sites that are on high ground in severe lightning areas, that are on dry, poorly conductive soil or that have wire runs longer than 100 feet.
Lightning arrestors are designed to absorb voltage spikes caused by lightning, allowing the surge to bypass wiring and equipment. They are connected to wires just before they enter any part of the solar system. Most wires running more than 100 feet will experience lightning-induced transients at some time. Because the transient is usually initiated at some point between the two ends of the wire, most applications will install a lightning arrestor just before the wire enters the equipment to be protected. The lightning arrestor is also connected to ground and routes the energy from the over-voltage transient to ground. Lightning arrestors are made of various voltages for both AC and DC.
