Bonding is simply a matter of connecting all of the electrical systems and metallic masses within a facility together, so they have the same electrical potential. Grounding consists of connecting the properly bonded equipment mass to the earth upon which the structure is located.
The recommended industry standard for grounding design is a “single point reference,” for services and equipment. Simply put, this means that the entirety of the equipment is attached and is connected to the grounding system at one point. This eliminates any differential in potentials of the grounding systems from equalizing through the structure and its equipment. The main electrical service ground should be the main point of ground reference for all of the systems in the structure or system implementation.
Quality transient voltage surge suppression products should be installed on all incoming electrical, telephone, cable, and data lines to protect all internal equipment from direct surges coming from service providers as well as secondary and electromagnetic effect damages which is caused by inductive coupling onto wiring.
It is crucial that a staged approach is taken to prevent internally generated transients from being dispersed throughout the structure. Research performed by IEEE tells us that many transients and surges experienced are actually generated internally. A staged approach protects equipment at all levels of location and prevents damaging transients from being created and/or carried through your structure once they pass the service entrance. A typical staged approach to SPD installation would entail installation of a heavy-duty SPD at the main service entrances to handle large incoming surges, a medium duty SPD at distribution equipment; and, small, fast-acting SPDs at the point of use. This protects the equipment from the outside world, as well as any internally generated transients.
Choice of SPD equipment and its point of installation play a critical role in the efficiency of the transient suppression system. The modes of protection, let-through voltage between these modes, insertion loss, the response time of the circuit, life of circuit, and its heat dissipation capacity are deciding factors in choosing SPD devices. The point of installation should be as close as possible to the device to be protected, and the connection leads should be as short as possible. It is paramount that wire routing is short, straight, and free of kinks.
Structural lightning protection systems are designed to protect the site from a direct lightning strike. The most common and best-known lightning protection system is the standard lightning rod, or Franklin system. The Franklin system is a series of metal rods and cables, which in the event of a lightning strike, are designed to carry the lightning energy safely to the ground and protect the facility from burning down. This type of system does nothing to protect the equipment within the structure from the secondary effects of lightning. In days gone by, this was adequate and acceptable. Today, things are different.
Charge dissipation technology (CDT) is a type of structural lightning protection system that has been developed over the past 30 years and is being used widely in communications and other industries. Charge dissipation, or charge redistribution, products are designed to bleed off the static ground charge that attracts a lightning strike to a structure. These devices are highly recommended for use on critical equipment sites to reduce the likelihood of a direct strike.
Using the described Three-Step Program to Success- ALLTEC’s Protection Pyramid™ method, as a guideline, this article reviews how the various lightning protection components integrate with each other and offers suggestions on how to assure the implementation of a successful system.