Lucent Technologies 555-670-116 manual MERLIN LEGEND Communications System Release, Issue, April

MERLIN LEGEND Communications System Release 7.0	Issue 1
Pocket Reference 555-670-116	April 1999
Power and Grounding	36

—A metallic underground water pipe must be supplemented by the metal frame of the building, a concrete-encased ground, or a ground ring.

—Other local metal underground systems or local underground structures such as tanks and piping systems.

—Rod and pipe electrodes, a 5/8-inch (1.6-cm) solid rod or 3/4-inch (1.9-cm) conduit or pipe electrode driven to a minimum depth of 8 feet (244 cm).

—Plate electrode, a minimum of 2 square feet (61 square cm) of metallic surface exposed to the exterior soil.

—Concrete-encased ground, which must be an electrode, consisting of one of the following:

—At least 20 feet (6.1 m) of one or more steel reinforcing rods, each being at least 1/2-inch (1.27 cm) in diameter.

—20 feet (6.1 m) of bare copper conductor not smaller than #4 AWG, encased in 2 inches (5 cm) of concrete. This electrode must be located within and near the bottom of a concrete foundation or roofing that is in direct contact with the earth.

—Ground ring, consisting of at least 20 feet (6.1 m) of bare copper conductor not smaller than #2 AWG, encircling the building. The ground ring must be in direct contact with the earth and buried at least 2.5 feet (77 cm) below the earth’s surface.

!WARNING:

Do not use a metal underground gas piping system. This is a safety risk.

For most power surges, the following standard grounding requirements provide adequate lightning and surge protection:

—Properly wired/grounded/bonded outside line protectors

—Properly wired/grounded AC outlet

—Properly grounded single-point ground bar

—Properly wired connection between single-point ground and power supplies

Additional Power Surge Protection

The 391C1, 391A3, 391A2, and 391A1 power supplies have built-in AC line protection. This built-in protection handles almost all situations.

Occasionally, additional protection may be needed if the customer is located in a heavy lightning area. The following products are available:

—The 147A protector provides AC surge protection for In-Range Out-of-Building (IROB) extensions. This protector can also provide surge protection for the 391A power supply module in heavy lightning areas.