Grounding Requirements - AT&T MERLIN LEGEND Release 2.0 Installation Section

Installing the Control Unit

Grounding Requirements

Proper grounding of the installation site safeguards system functioning by
protecting the system from the following:
lightning
power surges
power crosses on central office trunks
electrostatic discharge (ESD)
When installing the control unit, make sure that you meet the following
grounding requirements:
The control unit, the central office trunk 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 that the ground point for the central office
trunk protector be bonded to the AC power ground as shown in
Figure 2-3.
The AC outlet and the single-point ground bar must be properly
grounded as shown earlier in Figure 2-1.
Each power supply in the control unit must be connected to the
single-point ground bar by a #12 AWG or a #14 AWG solid copper
wire. Figures 2-1 and 2-3 show this connection.
This wire run should be as short as possible, preferably within 5 ft
(152 cm), not to exceed 10 ft (305 cm). This procedure is described
later in this chapter under "Providing the Proper Grounding."
The AC outlet must be connected to the 147A protector with #12 AWG
or a #14 AWG solid copper wire.
Power and Grounding
2-11