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Chapter 4 Outdoor Equipment Maintenance
Redline Communications Inc. Confidential and Proprietary
Components of Your Lightning Protection System
The purpose of your lightning protection systems is to re-direct a lightning strike a
preferential path to the ground. A typical lightning protection system has five major
components: strike termination, down conductor, grounding, ground reference and surge
suppression subsystem.
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Strike Termination—Strike terminations are objects that intercept the lightning strike.
Commonly, pointed metal rods are used for this purpose and are called air terminals
or lightning rods. Strike terminations can also take the form of overhead wires or
structural components of buildings. Strike terminations only influence the path of
lightning through the air at very close ranges (approximately twenty feet).
Note
These termination objects do not attract lightening. If a strike termination on your
building is hit, it likely would have bit by lightening regardless of whether strike
terminations were present.
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Down Conductors—This is an electrical path of low impedance that connects the strike
termination subsystem to the grounding subsystem. Commonly, these are wires but a
building’s steel-frame structural components can also be used.
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Grounding—The grounding subsystem sinks the lightning current into the earth.
Commonly, the grounding subsystem consists of ground rods, copper or steel rods
driven into the earth. The key parameter for the grounding system is low impedance.
The impedance of the grounding system is the total of the overall impedance of the
lightning protection system, so a high impedance grounding system can increase the
chance of flashover resulting in other damaging effects.
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Ground Reference (including bonding)—The ground reference subsystem and
electrical bonding is often the most elusive portion of a lightning protection system.
This subsystem electrically bonds all other electrical grounds and metal parts that may
provide an alternate ground path in a structure to your lightning protection system.
Despite the need for bonding, designers have to be careful not to install bonding that
provides an incidental ground path through sensitive electronics - a common oversight.
The CADWELD® process is a method of making electrical connections of copper to
copper or copper to steel. CADWELD® connections can be used to make grounding
connections for RedMAX outdoor equipment.
Crimped or bolted connections cannot be inspected visually, but CADWELD®
connections can be visually inspected and such an inspection provides an indication
of the quality of the weld. Refer to the Installers and Inspectors Guide for CADWELD®
Electrical Connections for detailed information and a visual reference of acceptable
welds.
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Surge Suppression—Once the building has physical lightning protection, protection
from the indirect effects of a lightening strike is essential, especially if sensitive
electronics are involved. Surge suppressors should be installed on the main data and
power entries and several devices should be installed inline to protect the sensitive
electronic equipment.
