Page S-1
Repair and Service Manual
B
B
LIGHTNING PROTECTION AND GROUNDING
Read all of Section B and this section before attempting any procedure. Pay particular attention to Notices, Cautions, Warnings and Dangers.
GS-726-006
EFFECTIVE:
10/19/92
REVISION:
A
SUPERCEDES:
TITLE:
General Specification: Lightning Protection and Grounding
Rev -, ECN 027194
1. Grounding Requirements
For the purpose of this specification, building ground systems should serve two primary functions: personal safety and
equipment protection. In order to be effective, all elements and functions of building ground system must receive equal
consideration in design and installation. Once installed, it is up to the owner to adequately maintain the system by
implementing periodic inspections and ground tests in order to determine its effectiveness.
2. Ground Systems
All electronic equipment is inherently related to earth by capacitive coupling, accidental or incidental contact and inten-
tional connection. The earth forms a natural readily available form of common potential reference for all electrical cir-
cuits. For maximum effectiveness, grounding must be looked at from a total system viewpoint, with various sub-
systems comprising the total facility ground system. The interconnection of the various sub-systems into a building
ground system will provide a direct path, of known low impedance, between earth and the various electrical and other
equipment. This effectively extends an approximation of ground reference throughout the building. The total building
ground system is composed of an earth electrode system, a lightning protection system and an equipment fault pro-
tective system.
Resistance To Earth: The resistance to earth of the ground system should not exceed 10 ohms. Where the resistance
of 10 ohms cannot be obtained due to high soil resistivity, rock formations or other abnormal conditions, alternate
methods for reducing the resistance to earth must be considered.
Chemical Treatments: No salt, coke or other chemicals may be used to treat the soil in order to obtain the required
ground resistance readings. Approved methods of enhancement are bentonite clay or the GEM product for ground
enhancement as manufactured by Erico Products of Solon, Ohio.
Ground Tests: The resistance to earth of the ground system shall be measured by the “Fall of Potential Method”.
Acceptable resistance meters/testers are those manufactured by Biddle or AEMC.
3. Lightning Protection Requirements
The external lightning protection system shall be designed and installed by a contractor who specializes in the light-
ning protection field. The contractor must be listed with Underwriters Laboratories Inc. and be in good standing. All
work shall be under the direct supervision of a Certified Master Installer with current credentials from the Lightning
Protection Institute.
The materials and design for the structure will comply with the most recent edition of the National Fire Protection
Association Lightning Protection Code, NFPA 780 and the Materials Standard for Safety from Underwriters Laborato-
ries UL96. Materials for this project may be those of Harger Lightning Protection, 1066 Campus Drive, Mundelein, Illi-
nois (800-842-7437).
Upon completion of the project, the contractor will supply to the owner the Master Label issued by Underwriters Labo-
ratories.
4. Equipment Fault and Personal Safety System
The standard method of providing an equipment fault protection ground network is to run a good ground conductor
(green wire) through the conduit together with the AC distribution system. This method is required for all types of con-
duit, including metallic.
5. Ground Network Requirements
Install the conduit in accordance with local regulations or as prescribed by the National Electrical Code.
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