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July 19, 2004
Field Cabinet Grounding Requirements
Use the following requirements when grounding the PG-FlexPlus field cabinet:
Special attention must be given to the following site grounding details in order to minimize
CAUTION
lightning-induced equipment damage in areas of high lightning activity or low ground
conductivity.
• A minimum of two driven ground rods are required, one at each end of the PG-FlexPlus field
cabinet. When driven, the rods should be flush with or slightly below ground level to allow
inspection of the attached conductor.
• The ground wire from the left side of the field cabinet (side compartment end) is terminated
to the ground bus in the AC power panel. This wire should be run as directly as possible and
terminated, unspliced, to the ground rod (Figure 6 on page 14).
The ground wire from the right side of the field cabinet is connected to the field cabinet main
ground bus located at the bottom of the side compartment, as shown in Figure 6 on page 14.
A lug is provided with the field cabinet for this connection.
For AC grounding purposes, the field cabinet should be treated as a separate "building"
even when fed from a power pedestal, if this is acceptable to the local authority. When
treated as a separate structure, the neutral bus is bonded to earth ground in the AC power
panel per NEC Code Section 250-23. Bonding of the neutral at the field cabinet AC panel pro-
vides the best protection against lightning damage to the DC power system.
If the neutral is not bonded to earth ground in the field cabinet, the DC power system is at
CAUTION
increased risk of lightning damage. In this situation, common routing of neutral and ground
conductors within the power pedestal is critical to minimizing transients.
• When installing ground wires in a conduit, use of nonmetallic conduits is required.
• For installations involving multiple field cabinets, 6 AWG (16 mm
wires of minimum length should interconnect the field cabinets. Where field cabinets or ped-
estals are separated by less than 6 feet (1.8 m), they can share a common centrally located
ground rod. See Figure 7 on page 15 for a typical grounding arrangement.
Field Cabinet Grounding Procedures
Use this procedure and refer to
Normally, ground wires are installed beneath the foundation pad prior to pouring the concrete. Leave at
least 6 feet (2 m) of ground wire above the pad for ground rod A and at least 3 feet (1 m) for ground rod B.
After the pad is constructed and field cabinet is mounted to the pad, connect the ground wires. Pole, H-
frame, and wall-mounted field cabinets are grounded in a similar manner; a nonmetallic conduit may be
required to protect the ground wires when the field cabinet is mounted above the ground.
1. Route the 6 AWG (16 mm
entrance opening in the pad. (Install wire in optional ground wire duct, if provided.)
2. Connect ground wire to AC panel ground bus (see wiring diagram inside AC panel). Route the
ground wire through the unused strain relief that is provided in the bottom of the AC panel.
3. Route the 6 AWG (16 mm
entrance opening in the pad. (Install wire in optional ground wire duct, if provided.)
4. Connect ground wire to lug provided on the field cabinet ground bus. Use pliers to twist the
self-threading lug onto the ground wire.
ADC Telecommunications, Inc.
Figure 6 on page 14
to ground the PG-FlexPlus field cabinet.
2
) bare solid copper ground wire from ground rod A through the cable
) bare solid copper ground wire from ground rod B through the cable
2
SCP-PGCAB001-010-01H
2
) solid copper ground
13
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