Grounding Requirements - AT&T MERLIN LEGEND Release 3.1 System Planning Manual

Confirming the Location of the Control Unit

Grounding Requirements

Proper grounding of the installation site is essential for correct and safe
functioning of the system. Grounding protects the system against:
Lightning
Power surges
Power crosses on outside lines/trunks
Electrostatic discharge (ESD)
The telephone company is responsible for providing protection of outside
lines/trunks at the entrance to the site. The protection should consist of:
Carbon blocks or gas-discharge tubes connected to an approved
ground
Adequate bonding of the outside line/trunk protector ground and the
power-company ground
!
CAUTION:
Improper ground can result in equipment failures and service outages.
Verify that the AC power uses an approved ground for its primary ground
and that all voltage-limiting devices are attached to an approved ground.
Approved grounds are as follows:
The metal frame of the building
A metal water pipe connected to an underground water pipe that is in
direct contact with earth
An electrode encased by at least 2 inches of concrete and located
within and near the bottom of a concrete foundation or footing in
direct contact with earth
A copper ring that encircles a building and is in direct contact with
earth
For most surge occurrences, the following standard grounding requirements
provide adequate lightning and power surge protection:
Properly wired, grounded, and bonded outside line protectors
Properly wired and grounded AC outlet
Properly grounded single-point ground bar
Properly wired connection between single-point ground and power
supply
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