Lightning rods or 'air terminals' are only a small part of a complete lightning protection system. In fact, the rods may play the least important role in a system installation. A lightning protection system is composed of three main components:
Rods or 'Air Terminals' - The small, vertical protrusions designed to act as the 'terminal' for a lightning discharge. Rods can be found in different shapes, sizes and designs. Most are topped with a tall, pointed needle or a smooth, polished sphere. The funtionality of different types of lightning rods, and even the neccessity of rods altogether, are subjects of many scientific debates. Lightning Cable.
Conductor Cables - Heavy cables (right) that carry lightning current from the rods to the ground. Cables are run along the tops and around the edges of roofs, then down one or more corners of a building to the ground rod(s).
Ground Rods - Long, thick, heavy rods buried deep into the earth around a protected structure. The conductor cables are connected to these rods to complete a safe path for a lightning discharge around a structure.
The conductor cables and ground rods are the most important components of a lightning protection system, accomplishing the main objective of diverting lightning current safely past a structure. The 'lightning rods' themselves, that is, the pointy vertically-oriented terminals along the edges of roofs, do not play much of a role in the functionality of the system. A full protection setup, given good cable coverage and good grounding, would still work sufficiently without the air terminals.
Lightning protection facts- Rods and protection system don't attract ligtning, nor do they where lightning will strike.
- Rods or protection systems do not and cannot prevent lightning, nor can they 'discharge' thunderstorms.
- Lightning protection systems (including placement of rods, cables, and groundings) are custom-designed for individual structures and require complex engineering to function properly. They should only be installed by qualified contractors.
- Lightning protection systems do not always prevent damage to electronics or computers. You should still unplug such devices during thunderstorms to ensure sufficient protection
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