D200-63-00
2
I56-931-02
Mounting
Each 1112/24B and 1112/24BA detector is supplied with a
mounting bracket that permits the detector to be mounted:
1. To a single gang box, or
2. Directly to a 3
1
/
2
-inch or 4-inch octagonal box, or
3. To a 4 inch square electrical box by using a plaster ring.
Wiring Installation Guidelines
All wiring must be installed in compliance with the Na-
tional Electrical Code, applicable local codes, and any spe-
cial 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 reduce the likelihood of
wiring errors. Improper connections can prevent a system
from responding properly in the event of a fire.
The screw terminal block accepts 14 – 22 gauge wire. For
best system performance, all wiring should be installed in
separate grounded conduit. Do not mix fire system wiring
in the same conduit as any other electrical wiring. Twisted
pair may be used to provide additional protection against
electrical interference.
A78-2336-01
P
W
R
OPTIONAL CLASS A WIRING
EOL RESISTOR
SPECIFIED BY
PANEL
MANUFACTURER
EOL POWER
SUPERVISION
RELAY (SHOWN
ENERGIZED)
A77-716 12/24V
POWER
TO
DETECTORS
UL LISTED
CONTROL
PANEL
INITIATING
LOOP
+
–
+
–
P
W
R
+
+
–
–
N.O.
C
+
+
–
–
N.O.
C
Figure 2. 1112/24B and 1112/24BA detector
mounting bracket:
ALIGNMENT ARROWS
TAMPER RESISTANT TAB
(CUT OFF SMALL TAB TO
ACTIVATE TAMPER-RESIST
FEATURE)
Figure 1. Surface mounting 1112/24B and 1112/24BA
detectors on 3
1
/
2
-inch and 4-inch octagonal box:
A78-2563-00
,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,
A78-2333-02
Figure 3. Wiring diagram for the 1112/24B(A) detector:
Smoke detectors and alarm system control panels have
specifications for allowable loop resistance. Consult the
control panel specifications for the total loop resistance al-
lowed for the control panel being used before wiring the
detector loops.
Wire connections are made by stripping about
1
/
4
inch of
insulation from the end of the feed wire, inserting the wire
into the appropriate terminal, and tightening the screw to
secure the wire in place.
Tamper-Resist Feature
This detector includes a tamper-resist feature that prevents
its removal from the bracket without the use of a tool. To
make the detector tamper-resistant, remove the smaller tab
by breaking it at the scribed line on the tamper resistant tab
on the detector mounting bracket (see Figure 2), then in-
stall the detector. To remove the detector from the bracket
once it has been made tamper resistant, use a small screw-
driver to depress the tamper-resistant tab, located in the
slot on the mounting bracket (see Figure 4), and rotate the
detector counterclockwise.
