Lightning rod
Lightning rods come in many different forms, including hollow, solid, pointed, rounded, flat strips, or even bristle brush-like.
[citation needed] Franklin, unaware of Diviš's work, independently developed and popularized his own lightning rod design, which became widely adopted across Europe and North America.
Franklin's contribution significantly advanced the understanding and application of lightning protection systems, although Diviš's earlier conceptual work remains an important milestone in the history of electrical safety engineering.
[3] Franklin speculated that, with an iron rod sharpened to a point, "The electrical fire would, I think, be drawn out of a cloud silently, before it could come near enough to strike."
If after a storm a ball is discovered missing or broken, the property owner should then check the building, rod, and grounding wire for damage.
Balls of solid glass occasionally were used in a method purported to prevent lightning strikes to ships and other objects.
Hence the best method for preventing a lightning strike to a wooden ship was to bury a small solid glass ball in the tip of the highest mast.
In the 1990s, the 'lightning points' were replaced as originally constructed when the Statue of Freedom atop the United States Capitol building in Washington, D.C. was restored.
Secondary "side-flashes" can be enough to ignite a fire, blow apart brick, stone, or concrete, or injure occupants within a structure or building.
[7] Field applications have mainly been derived from trial and error based on the best intended laboratory research of a highly complex and variable phenomenon.
Diviš's apparatus was, according to his private theories, aimed towards preventing thunderstorms altogether by constantly depriving the air of its superfluous electricity.
Smaller versions of lightning arresters, also called surge protectors, are devices that are connected between each electrical conductor in a power or communications system, and the ground.
These conductors, often referred as to "static", "pilot" or "shield" wires are designed to be the point of lightning termination instead of the high-voltage lines themselves.
These conductors are bonded to earth either through the metal structure of a pole or tower, or by additional ground electrodes installed at regular intervals along the line.
The monitoring device switches off the transmitter when the antenna shows incorrect behavior, e.g. as a result of undesired electrical charge.
If after several attempts the antenna continues to show improper behavior, possibly as result of structural damage, the transmitter remains switched off.
At the very least, the arc current will damage the lightning conductor and can easily find another conductive path, such as building wiring or plumbing, and cause fires or other disasters.
[14] Additional precautions must be taken to prevent side-flashes between conductive objects on or in the structure and the lightning protection system.
This voltage difference can be large enough to cause a dangerous side-flash (spark) between the two that can cause significant damage, especially on structures housing flammable or explosive materials.
The most effective way to prevent this potential damage is to ensure the electrical continuity between the lightning protection system and any objects susceptible to a side-flash.
Effective bonding will allow the voltage potential of the two objects to rise and fall simultaneously, thereby eliminating any risk of a side-flash.
A modeling system based on a better understanding of the termination targeting of lightning, called the Rolling Sphere Method, was developed by Dr Tibor Horváth.
Locations that are considered safe from lightning can be determined by imagining a leader's potential paths as a sphere that travels from the cloud to the ground.
[21] It is difficult to resolve the controversy because proper controlled experiments are nearly impossible, but work performed by Charles B. Moore, et al.,[22] in 2000 has shed some light on the issue, finding that moderately rounded or blunt-tipped lightning rods act as marginally better strike receptors.
According to an early patent, since most lightning protectors' ground potentials are elevated, the path distance from the source to the elevated ground point will be shorter, creating a stronger field (measured in volts per unit distance) and that structure will be more prone to ionization and breakdown.
Initially, an NFPA independent third party panel stated that "the [Early Streamer Emission] lightning protection technology appears to be technically sound" and that there was an "adequate theoretical basis for the [Early Streamer Emission] air terminal concept and design from a physical viewpoint".
[33] The NFPA withdrew its proposed draft edition of standard 781 due to a lack of evidence of increased effectiveness of Early Streamer Emission-based protection systems over conventional air terminals.
Members of the Scientific Committee of the International Conference on Lightning Protection (ICLP) have issued a joint statement stating their opposition to Early Streamer Emission technology.
This means that a strike on an uninstrumented structure must be visually confirmed, and the random behavior of lightning renders such observations difficult.
Whilst controlled experiments might eventually become feasible, very good contemperaneous data is obtained via specialized radio receivers which record the characteristic electrical "signature" of lightning strikes.
