AT&T MERLIN LEGEND Installation & Maintenance Manual page 101

Preparation
Each carrier requires one outlet receptacle. Additional AC outlets
may be required for auxiliary equipment. All AC outlets must be
connected to the same load center and must have the ground
wire connected to the single-point ground bar on the first AC
outlet (see Figure 11).
If a printer or a PC is installed with the system, it must be
plugged into the same AC branch as the power supply module
of the basic carrier. If the printer or the PC is 50 or more feet from
the CU, asynchronous data units (ADUs) must be installed. (See
Chapter 3, "Installation," for procedures for Station Message
Detail Recording (SMDR) printer and PC installations.)
CAUTION:
The AC outlet for the CU should not be switch controlled.
Plugging the CU into an outlet that can be turned on and off
by a switch invites accidental disconnection of the system.
The AC outlet must be properly wired (see "AC Outlet Tests"
below).
AC Outlet Tests
The system must be connected to a properly grounded AC
outlet. The two methods recommended for verifying proper
grounding at the AC outlet are described in the following pages.
See Table 2-5 for AC power requirements.
If the AC outlet test detects any of the following faults, have them
corrected before installing the CU:
open ground
reversed polarity
open hot
open neutral
hot and ground reversed
hot on neutral with hot open
Power and Grounding 2-9