Which element is crucial for preventing side flash in a lightning protection system?

In a lightning protection system, bonding plays a vital role in preventing side flash, which is the dangerous phenomenon where lightning jumps from one conductive object to another. Proper bonding ensures that all conductive elements within the protection system are electrically connected to create a unified path for lightning currents. This uniformity helps to distribute lightning energy evenly among all connected components, reducing the potential for differential voltage that could lead to side flashes.

When bonding is effectively implemented, it minimizes the risk of a potential difference occurring between various parts of the system or between a structure and surrounding conductive objects. This is especially important in environments where multiple grounding points may exist, as any disparity in voltage between these points can result in lightning seeking an alternative path, causing side flashes.

While other elements like air terminals, fasteners, and ground terminals are integral parts of a lightning protection system, they serve specific functions that do not directly address side flash prevention as effectively as bonding does. Air terminals capture the lightning strike, fasteners secure the components, and ground terminals provide a path for the lightning energy to dissipate safely into the earth, but it is the bonding that ties these components together and mitigates the risks of flashover events.