Lighting rod


A lightning rod is a metal narrow piece or rod, typically of copper or similar conductive material, used as part of lightning security to guard tall or isolated structures from lightning damage. Its formal name is lightning finial. Sometimes, the system is informally referred to as:

A lightning conductor,
A lightning arrester, or
A lightning discharger.
However, these terms really refer to lightning guard systems in general or specific mechanism within them.

Lightning rod dissipaters make a structure less nice-looking by which charges can flow to the air around it. This then reduces the voltage between the point and the storm cloud, making a strike less likely. The most common charge dissipaters appear as slightly-blunted metal spikes sticking out in all information from a metal ball. These are mounted on short metal arms at the very top of a radio antenna or tower, the area by far most likely to be struck. These devices diminish, but do not eradicate, the risk of lightning strikes.

Arrestors
A lightning arrestor is a mechanism that shunts or diverts the huge voltage and electrical current of a lightning hit to an earthed ground. Electrical equipment can be protected from lightning by an arrester, a device that contains one or more gas-filled spark gaps between the equipment's cables and earth. An arrester is designed to handle much higher jolts of electricity than a surge protector, which cannot handle a direct strike at all.
When lightning exceeds the arrestor's breakdown voltage, the currents arcs to the ground and prevents arcing around inside sensitive electronic equipment joined further down line. The glimmer gap may be filled with a noble gas, or with air. Other types may work by overcrowding normal irregular current, but allowing the direct current from a lightning discharge.
Lightning arrestors are normally installed on electric power broadcast lines, and on radio tower feed lines between the radio antenna and spreader. Smaller ones can also be installed on the mains electricity service coming into a building, just before the circuit breaker panel. Telephone wires also have fusible links sometimes where they enter a building, joined by carbon which will vaporize with very high current.