D450-03-00
2
I56-374-05R
Mounting
This detector base mounts directly to 3
1
⁄
2
-inch and 4-inch
octagon boxes, and 4-inch square boxes (with or without
plaster). To mount the base, remove the decorative ring by
rotating it in either direction to unhook the snaps before
separating the ring from the base. Use the screws supplied
with the junction box to attach the base to the box through
the appropriate slots in the base (see Figure 1). Position the
decorative ring around the base and rotate it in either direc-
tion until the ring snaps into place.
Installation Guidelines
All wiring must be installed in compliance with the
National Electrical Code, all applicable local codes, and
any special requirements of the authority having jurisdic-
tion, using the proper wire size. 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.
For signal wiring (the wiring between interconnected
detectors), it is recommended that the wire be no smaller
than 18 gauge (1.0 square mm). The screws and clamping
plate in the base can accommodate wire sizes up to 12
gauge (2.5 square mm). For best system performance, the
power (+ and –) loop wire should be twisted pair and
installed in separate grounded conduit to minimize the
effects of electrical interference.
Smoke detectors and alarm system control panels have
specifications for allowable loop resistance. Read the man-
ual for the control to determine the total loop resistance
allowed before wiring the detector loops.
Locate installations where normal ambient temperature
does not exceed 100°F.
Wiring Instructions
Wire connections are made by stripping approximately
3/8" (1 cm) insulation from the end of each wire, sliding
the bare end of the wire under the clamp plate, and tight-
ening the clamping plate screw. Use the strip gauges mold-
ed into the inside and underside of the base for ease of
wiring to terminals 1 through 5 and to terminals 12 through
14, respectively.
The zone wiring of the detector base should be checked
before installing the smoke detector head. To make this
possible, this base contains a special-type shorting jumper.
After the detector base is wired and attached to the electri-
cal box, make sure that the shorting spring is in contact
with the base of terminal 3. This temporary connection
SNAP ON
DECORATIVE
RING
SCREWS (NOT
SUPPLIED)
DETECTOR
BASE
BOX (NOT
SUPPLIED)
SHORTING
SPRING
Figure 1. Mounting base to box:
shorts the positive-in and positive-out leads and permits
the wiring of the loop to be checked for continuity.
Once all the detector bases have been wired and mounted,
and the loop wiring has been checked, the detector heads
may be installed in the bases. The shorting spring in the
base will disengage automatically when the detector head
is removed from the base. DO NOT remove the shorting
spring since it reengages as the detector head is turned into
the base, completing the circuit.
A78-1175-01
