System Sensor 2412AT, 2424AT and 2424AIT Direct Wire - Manual (Page 2)

D400-04-00 2 I56-288-05
Mounting Instructions
Each 2400 Series detector unit is supplied with a mounting
bracket kit that permits several mounting techniques:
1. Units may be mounted directly to a 3-inch or 4-inch octagonal,
1 1 /
2
inch deep electrical box. (See Figures 1 and 2.)
2. Units may be mounted to a 4-inch square electrical box by
using plaster ring with the supplied mounting bracket kit.
Tamper-proof Feature
This detector includes a tamper-proof feature that, when
activated, prevents removal of the detector without the use
of a tool. To activate this feature, cut off smaller tab at the
scribe line on tamper-proof tab located on the detector
mounting bracket (see Figure 2). Install the detector. To
remove the detector from the bracket once the tamper-
proof feature has been activated, depress the tamper-proof
tab located in the slot on the mounting bracket and turn the
detector counterclockwise for removal.
Installation In Australia Only
The installation temperature range for Australia is 5
°
to
45
°
C and has been tested per the Australian Standard.
Ignore installation temperatures specified for all other
applications when installing detectors in Australia.
Detectors should be installed by qualified technicians.
Installation of a mains connected power supply unit must
be performed by qualified electricians only. The primary
power will be provided by a panel type system. A recharge-
able battery is required as a backup to the external power
supply in case of a mains failure. In standby operation, the
backup battery (fully charged) must be capable of
providing uninterrupted power for at least 7 days to the
TAMPER
RESISTANT
TAB
TO MAKE DETECTOR TAMPER RESISTANT,
BREAK OFF TAB EXTENSION
AT SCRIBED LINE
A78-1411-00 A78-534-00
Figure 1. Flush mounting of detector on 4-inch
octagon box:
Figure 2. Detector mounting bracket:
system and all smoke alarms before the panel gives the
required battery-low signal. When the battery-low signal is
given, the battery should be capable of providing power for
another 7 days, after which the backup battery should have
enough energy left to allow a 4-minute alarm signal to be
given by all connected smoke alarms.
Wiring Installation Guidelines
All wiring must be in compliance with the National
Electrical Code and the applicable local codes, and any
special requirements of the local authority having
jurisdiction. Proper wire gauges should be used. The
conductors used to connect smoke detectors to control
panels and accessory devices should be color-coded to
prevent wiring mistakes. Improper connections can prevent
a system from responding properly in the event of a fire.
For signal wiring (the wiring between interconnected
detectors), wire no smaller than 18 AWG is recommended.
Wire sizes up to 12 AWG may be used. For best system
performance, the power (+and –) loop wires should be
twisted pair and installed in separate grounded conduit or
shielded cable to protect the loop from extraneous electrical
interference. If a cable shield is provided, the shield con-
nection to and from the detector must be continuous by
using wire nuts, crimping, or soldering as appropriate for a
reliable connection.
Wire connections are made by stripping about 3/8" of
insulation from the end of the wire (use strip gauge molded
in base), sliding the bare end of the wire under the
clamping plate, and tightening the clamping plate screw.
Do not loop the wire under the clamping plate.
Figure 3. Class A or Class B wiring diagram for model 2412AT and 2424AT detectors used with four-wire
control panels: