Lightning is known to be the most significant source of surges—bolts have been recorded to have a million to a billion volts and between 10,000 to 200,000 amps. However, lightning only makes up a portion of all transient events in a facility.

Because transients can originate from both external sources (like lightning) and internal sources, facilities ought to have both a lightning protection system and surge protection installed.

This begs the question: what is the difference between these two systems, and how do they work together?  

Grounding, bonding and lightning protection systems protect against electrical events that have potential for significant damage or downtime. These events are hopefully few and far between in the lifetime of a facility. However, lower energy transient events can occur more frequently that may go unnoticed, until one day a piece of electronic equipment stops working.

Significant damage can occur to the more robust systems as a result of lightning-induced surges resulting within a radius of several kilometers, or from repetitive switching-induced surges. Costs can range from degradation of electrical or electronic systems, to data loss and equipment destruction. Some of these costs can appear relatively minor, but the loss of an essential service or revenue associated with a facility or plant shut down can be enormous.