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GENERAL INSTRUCTIONS FOR PF
MODULAR ENCLOSURES FOR
TRANSFORMER SUBSTATIONS
IG-021-GB
version 07
29.08.2008
3.8. CONNECTING THE EARTH CIRCUIT
3.8.1. Panel Reinforcing Mesh
The panel reinforcing mesh is connected to earth via some of their slots or via inserted nuts.
Each type is described below:
Bottom plates
The reinforcing mesh in the bottom plates is connected to earth via all of their slots.
Front Panels
These have earth connections in the 2
nd
and 4
th
slots, counted from the bottom.
Side Panels
These have earth connections in the 2
nd
and 4
th
nuts, counted from the bottom.
Floor plates
These have an M12 threaded insert for the earth connection.
Covers
The covers have earth connections in their end slots, except for single-module
covers, that have an M12 nut for the earth connection.
To allow correct earthing, PF Modular Transformer Substations have an interior protective
earthing circuit that allows the entire concrete enclosure to form an equipotential surface.
The reinforcing meshes in the different concrete components are connected together as
follows:
1.
The vertical panels are joined mechanically.
2.
The joints between covers, and between these and the vertical panels, are made
using a 50 mm
2
cross-section bare cooper wire between the suitable slots, except in
the case of a single-module covers where the connection is made between the M12
nut and the slot in the front or rear panels.
Figure 3.70