On the roof of the building, a system of lightning protection conductors and lightning rods is constructed to intercept any lightning before it impacts the building. The conductors are carried on top of the exterior wall of the building, and when they reach the top of the wall, they cross over to the opposite side where they continue down the next wall section. When all the walls have been crossed, the conductors terminate in a single metal point that is attached to the ground. This prevents any electrical charge within the conductor from reaching the end and causing more damage.
The protective structure for buildings shown in Figure 3-1 requires that each floor be equipped with a set of conductors to form a circuit between them. These circuits are then connected at the roof level so that no floor is isolated from the others. Each conductor is made of aluminum because it is very resistant to corrosion by water and does not require maintenance like copper wires can do over time. Aluminaiudes are also very strong, so much so that some houses are built using their own cross-sections instead of relying on steel or wood for their structural support.
Figure 3-1. Protective wiring system for a building (Source: Iowa State University)
These rods are installed on rooftops to attract lightning and protect structures from lightning strikes. A lightning rod is installed where cables enter a structure to protect electrical devices and ensure the safety of people around. The protection given by the ground conductor is very important; without it, the building would be at risk of damage due to power surges caused by direct hits from lightening.
Lightning has two paths to travel when striking a structure: through the grounding system and then back into the sky via the earthing system. If an electrical path cannot be found through you ground rod, then it must find its way back to Earth through another route, which could cause serious damage to your home or business.
The ground rod should be in contact with the earth beneath you, so make sure it's in a safe place near your house and that it's not damaged. If you're not sure how to connect it properly, call in a professional electrician. They will know how to do this safely, securely and effectively.
Lightning can strike anywhere at any time, so keep an eye out for warning signs such as lights flashing across roofs or trees being hit with a spark. If you see anything out of the ordinary, call for help before trying to rescue anyone from a struck tree or building.
A lightning rod (and the associated protection system) is intended to protect a home or structure against direct lightning strikes and, in particular, lightning-initiated fires. The metal rod acts as an antenna that collects energy from nearby clouds while the distance rod can be extended away from the house for far-away storms.
The grounding of aircraft wiring also uses a similar principle of operation. While the metal chassis of an aircraft serves as a good conductor of electricity, the plastic body does not; instead, it provides a path for current to follow around the airplane's frame. If this current encounters something with which it cannot conduct (such as another metal part), then it will find its way back to earth through your body! This is why you must always wear current-carrying equipment such as wire mesh vests when working on aircraft.
Lightning has the potential to start fires when it hits the ground or objects near the ground. This happens because the heat from the strike melts materials in the area, causing liquids to run off into rivers or lakes. This is why it is important to clear away any trees or other vegetation close to the ground. Otherwise, they will act as fuel for any future storms.
While lightning rods can assist protect a structure from direct lightning strikes, a comprehensive lightning protection system is required to help avoid damaging electrical surges and potential fires produced by lightning entering a structure through cables and pipes.
The purpose of a lightning rod is to provide an easy path for current to return to its source when it enters a building through a metal object such as a pipe or cable. This prevents current from flowing into other parts of the building and creating a hazard. A lightning rod does not prevent all damage caused by lightning strikes, but it can reduce the risk of fire.
There are two types of lightning rods: ground-based and aerial. An aerial rod attaches to the roof or outer wall of a building and extends upward toward heaven. This allows it to receive current from any cloud that contains a charge. The grounding mechanism on an aerial rod works like a fuse: If electricity reaches the rod before it reaches the end, there's a low-current short circuit. This doesn't open up again until after the storm has passed. But if the wire is broken before this happens, then the rod acts as a normal ground connection and allows current to flow back to the building power line.
A ground-based rod connects to the earth outside of the building. It works like an aerial rod in that it receives current from any nearby cloud that contains a charge.