AT&T MERLIN LEGEND Installation & Maintenance Manual page 103

Preparation
Grounding Requirements
Proper grounding (see Figure 12) of the installation site
safeguards system functioning by protecting the system from
lightning
power surges
power crosses on CO lines/trunks
electrostatic discharge (ESD)
The telephone company is responsible for providing protection
of CO 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 CO line/trunk protector ground and
the power company ground
The CU, the CO line protector, and the AC power service panel
should be as close to each other as possible. Because
equipment can be located throughout a building, the National
Electrical Code requires the ground point for the CO line
protector to be bonded to the AC power ground. The AC outlet
and the single-point ground bar must be properly grounded.
Power and Grounding 2-11