AT&T AT&T manual Grounding, Lightning Protection

Grounding

Connection of an approved ground to the system cabinets is essential. An approved ground may consist of any of the following:

● Grounded Building Steel - The metal frame of the building.

●Water Pipe - A continuous metal water pipe, not less than l/2 inch in diameter, that is

connected	to an underground metal water pipe that is in direct contact with earth for
10 feet or	more.

●Concrete-Encased Ground - An electrode encased by at least 2 inches of concrete and located within and near the bottom of a concrete foundation or footing indirect contact

with the earth. The foundation must consist of at least 20 feet of one or more steel reinforcing bars or rods of not less than 1/2 inch in diameter, or at least 20 feet of bare, solid copper wire not smaller than No. 4 gauge.

● Ground	Ring -A	ring that encircles a building or			structure indirect contact with earth
at a depth of at		least 2-1/2	feet. The	ring must	consist of at least 20 feet of bare
copper	conductor	not smaller	than No. 2	gauge.

Lightning Protection

A Coupled Bonding Conductor (CBC) tie-wrapped to all trunks provides lightning protection. The CBC can be any one of the following:

●A 16 gauge ground wire

● Continuous cable sheath

●Six unused pairs of wire

The CBC should be run from the telephone company provided network interface to the system Cabinet 1’s ground block. If the telephone company has not extended the CBC from the facility entrance to the network interface, the System 25 installer should run the CBC along the same route as the incoming facilities, where feasible.

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