Installation guide

Bosch Security Systems | 11/03 | 39352E
EN | 14
D9124 | Operation & Installation Guide |
3. Overview
3.4 Connecting the Earth Ground
3.4.1 Wire Connections to Earth Ground Stud
High voltage is present. Lock out the circuit
breaker before proceeding.
Make all connections to the 120 VAC
terminals as directed by NEC 70.
For safety and to help prevent damage from electrostatic
charges or other transient electrical surges, you must
first ground the system before making any other
connections. Before connecting the green wire from the
120 VAC service, crimp a connector to the end of it.
Refer to Figures 2 and 4 to place objects on the Earth
Ground stud in the following order:
1. Place a star washer on the stud.
2. Slip the green wire from the 120 VAC service onto
the star washer on the stud.
3. Place the hex nut on the stud and tighten firmly.
4. Repeat Steps 1 through 3 for the two green wires in
wiring harness J1 on the upper battery shelf.
3.4.2 Ground Fault Detect Enable
Ground fault detect capability is available
only on firmware versions 6.10 or higher.
Ground fault is defined as “a circuit impedance to earth
ground of approximately 95 kΩ or less.” The control
panel detects a ground fault on Terminals 1 to 9 and
Terminals 11 to 32 if the Ground Fault Detect Enable
jumper (S4) shown in Figure 6 is locked (closed) and a
non-zero value is entered in Area 5 Silent Alarm Relay.
(Refer to the D9412G/D7412G Program Entry Guide.)
However, the D9124 defaults to 128.
When the jumper is in the unlocked (open) position, the
panel does not detect ground fault conditions. If a
ground fault condition occurs, the command centers
display SERVC GND FAULT and the control panel
transmits a Trouble Report Ground Fault Area 1
(Modem IIIa
2
format only). For the control panel to
detect a ground fault condition, it must see the ground
fault for at least 30 consecutive seconds. When the
control panel recognizes the ground fault condition is
corrected, a Restoral Report is sent. For the restoral
condition to be met, the ground fault must be corrected
for 5 seconds to 45 seconds consecutively.
The D9124 Fire Alarm Control Panel logs
and prints a Ground Fault Event as a Trouble
Point 256.
1 - Nut
2 - Lug
3 - Star washer
4 - Stud
5 - Sheet metal panel
Figure 4: Wire Connection to Earth Ground Stud
1
2
3
2
4
5
2
Figure 5: Ground Fault Detect
1 - With S4 closed, control panel detects ground
faults.
2 - With S4 open, control panel does not detect
ground faults.
3 - Ground fault detect enable (S4)
GROUND FAULT DETECT
Enabled
Disabled
PHONE
LED
RED
ON WHEN
COMMUNICATING
OFF WHEN IDLE
LOOP START
PHONE MONITOR SELECT
GROUND START
Requires
Relay # D136 in
Ground
Start Socket
GND START
1
3
2