Approved Grounds - Avaya G250 Installing And Upgrading

Installing the Avaya G250 Media Gateway

Approved grounds

An approved ground is the closest acceptable medium for grounding the building entrance
protector, entrance cable shield, or a single-point ground of electronic telephony equipment. If
more than one type of approved ground is available on the premises, the grounds must be
bonded together as required in Section 250-81 of the NEC for the US or per the local electrical
code regulations in the country of installation.
Grounded Building Steel. The metal frame of the building where it is effectively grounded
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by one of the following grounds: acceptable metallic water pipe, concrete encased ground,
or a ground ring.
Acceptable Water Pipe. A metal underground water pipe, at least 1/2-in. (1.3 cm) in
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diameter, in direct contact with the earth for at least 10 ft. (3m). The pipe must be
electrically continuous (or made electrically continuous by bonding around insulated joints,
plastic pipe, or plastic water meters) to the point where the protector ground wire connects.
A metallic underground water pipe must be supplemented by the metal frame of the
building, a concrete-encased ground, or a ground ring. If these grounds are not available,
the water pipe ground can be supplemented by one of the following types of grounds:
- Other local metal underground systems or structures, such as tanks and piping
systems.
- Rod and pipe electrodes. A 5/8-in. (1.6 cm) solid rod or 3/4-in. (2 cm) conduit or pipe
electrode driven to a minimum depth of 8 ft. (2.4 m).
- Plate electrodes. Must have a minimum of 2 sq. ft. (0.185 sq. m) of metallic surface
exposed to the exterior soil.
Concrete Encased Ground. An electrode encased by at least 2 in. (5.1 cm) of concrete
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and located within and near the bottom of a concrete foundation or footing in direct contact
with the earth. The electrode must be at least 20 ft. (6.1 m) of one or more steel reinforcing
bars or rods, 1/2-in. (1.3 cm) in diameter, or at least 20 ft. (6.1 m) of bare solid copper, 4
AWG (26 mm
Ground Ring. A buried ground that encircles a building or structure at a depth of at least
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2.5 ft (0.76 m) below the earth's surface. The ground ring must be at least 20 ft. (6.1 m) of
2 AWG (35 mm
Approved Floor Grounds. Floor grounds are those grounds on each floor of a high-rise
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building that are suitable for connection to the ground terminal in the riser closet and to the
cabinet single-point ground terminal. Approved floor grounds may include the following:
- Building steel.
- The grounding conductor for the secondary side of the power transformer feeding the
floor.
- Metallic water pipes.
- Power-feed metallic conduit supplying panel boards on the floor.
- A grounding point specifically provided in the building for that purpose.
36 Installing and Upgrading the Avaya G250 Media Gateway
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) wire.
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), bare copper wire.