Tall buildings have lightning conductors to help transport the electrical current from a lightening strike to the ground safely. This protects the structure's electrical equipment and the materials used within the building.
Lightning conductors, commonly referred to as lightning rods, don’t actually attract lightning strikes. In fact, it is difficult to affect the path of lightning from the ground due to the long distance lightning travels to reach the Earth’s surface. The purpose of lightning rods is to provide grounding to the buildings. This means that any electrical current that strikes the building is guided on a specific path straight to the ground, where it is safely dispersed. When lightning strikes a building that does not have proper lightning protection, it often overloads any internal electrical systems. This includes the building's internal wiring, and thus any devices plugged into that system. Overloading the system leads to damaging of the equipment and possible sparks or electrical fires.
Another possible outcome of a lightning strike without proper protection is turning any lingering moisture within the walls of the building into steam. This has the potential to damage the building's insulation and its ability to maintain safe temperatures during different types of whether.