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Earthing the site
Cross bonding
Foundation metalwork must be connected to the earth electrode network. The
earth system must also be cross-bonded to an adjacent antenna mast, with two
connections made between the two systems. All earth cable terminations must
be crimped, clamped or welded; soldered joints are not permitted.
Earthing
procedure
The cabinet equipment must be earthed as detailed in this procedure. Make
provision for routeing the earth cables into the site and to the cabinet before
beginning installation of the system racks.
Excavate the site to accommodate the foundation to a depth determined by the
site architect. For the earth components to be used, refer to Figure 2-4 and
proceed as follows:
1.
2.
3.
4.
5.
Earth electrode
testing
Earth electrodes should be tested as detailed in BS7671 16th Edition or
equivalent national and regional regulations. One of three methods of earth
electrode test (earth mat) is used:
S
S
S
The method of test to be used at a specific site is determined by the site
conditions, the extent of the earth system and the limitations of the site
boundaries. The method used at the site is to be determined from the earth
electrode compliancy certificate and repeated annually. Before proceeding with
the test, ensure that the resistance of the test leads is less than 0.05 ohms.
Inst. 2–14
Drive a minimum of four copper earth rods 2.4 m long below the surface,
and connect these rods together with 70 mm cross-sectional area (CSA)
solid conductor.
Connect the earth rods to the cabinet earth busbar via a 70 mm CSA solid
conductor.
Check that the earth electrode installation resistance is less than 10 ohms.
If the resistance is greater than 10 ohms, install more earth rods to bring
the resistance within specification.
Cross-bond the earth system to the adjacent antenna mast earth with
conductors of 70 mm CSA, buried at a depth of not less than 500 mm.
Bond equipment such as fences, fuel tanks, metal buildings, or steel
building skids associated with the site to the closest earthing rod or
bonding wire.
Fall of potential.
61.8% rule.
Slope method.
Installation & Configuration: Horizon macro outdoor
68P02902W03-A
CONTROLLED INTRODUCTION
GSM-204-423
31st Oct 01
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