ERICO Practical Guide to Electrical Grounding - Manual (Page 39)

31 Chapter 2: Building Lightning Protection
necting or bonding of the two systems helps to ensure that
there is little possibility of a difference of potential between
the two systems or the two systems’ components.
Because this bonding requirement is difficult to implement
in many facility installations, some low impedance
screened down conductors are being used successfully by
ERICO in Australia and Asia. These conductors are
specially constructed and therefore relatively expensive, but
the reduced chance of side flashes and the ease of
installation are very attractive.
Connectors bond the conductors to the air terminals,
structures, equipment and ground electrodes. They can be
mechanical devices or exothermic welded connections.
Connections to thin metal or to aluminum items must be
mechanical. A properly made connection must last as long
as the planned life of the facility and have:
1. Adequate mechanical strength to withstand the
forces of nature and any outside force it may
encounter.
2. High thermal capacity for high current surges.
3. Low and constant impedance.
4. Corrosion resistance.
5. No electrochemical deterioration when joining
different materials.
Grounding electrodes make the connection between the
lightning protection system and the earth. The lightning
electrodes must be bonded to all other grounding system
Plate Electrode
Fig. 2-14
24 Feet Minimum
24" Minimum
12" x 12"
(1 Square Foot)
Shallow Sandy Soil
Fig. 2-13
12 Feet Minimum
12 Inch to 24 Inch
Minimum
Shallow Topsoil
Fig. 2-12
Moist Clay Soil
Fig. 2-11
10' Or More
Grounding Book 4/14/99 10/5/99 6:01 PM Page 31 (Black plate)