Conventional Products—DH400 Conventional Air Duct Smoke Detector 15
All wiring must be installed in compliance with the National Electrical
Code and the local codes 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 Initiating Device Circuit (IDC) wiring, (the wiring between
interconnected detectors and the fire alarm control panel), it is usually
recommended that the single conductor wire be no smaller than
18 American Wire Gauge (AWG) (1.0 square mm). The duct detector
terminals accommodate wire sizes up to 14 AWG (2.1 square mm). Wire
sizes up to No. 14 AWG (2.1 square mm) for Terminals 8-14 and
No. 12 AWG (3.3 square mm) for Terminals 1-5 may be used with the
base. For best system performance, the IDC wires should be a twisted pair
and installed in a separate grounded conduit to protect the IDC from other
types of circuits in the system.
The last foot of conduit should be flexible steel conduit (available in
electrical supply houses), which facilitates easier installation and puts less
strain on the conduit holes in the housing. Solid conduit connections may
be used if desired.
Smoke detectors and alarm system control panels have specifications for
maximum allowable IDC resistance and supervision current. Consult the
control panel manufacturer’s specifications for the total IDC resistance
and supervisory current allowed.
Figure 6: System Wiring Diagram for 2-Wire Duct Detectors
(Detectors Powered from the Initiating Circuit)
Wiring
Installation
Guidelines
S tyle D O p tio n a l W irin g (C la s s A )
d hfig1 5
5
3
4
1
2
U L L is te d
C o m p a tib le
2 -wire
C o n tro l P a n e l
In itia tin g
D e v ic e
C irc u it
In
+ O u t
In
O ut
S u p e rv is o ry
S witc h
F irs t D e te c to r
o n ID C D H 4 0 0
R A 4 0 0 Z (O p tio n a l)
R e m o te A la rm L E D
5 m A M a xim u m
2 .8 V D C
N o m in A la rm
5
4
3
1
2
In
O ut
In
O ut
S u p e rv is o ry
S witc h
L a s t D e te c to r
o n ID C D H 4 0 0
R A 4 0 0 Z (O p tio n a l)
R e m o te A la rm L E D
5 m A M a xim u m
2 .8 V D C
N o m in A la rm
E O L R
E n d -o f L in e
(E O L ) res is to r
s p e c ifie d b y p a n e l
m a nu fa c tu rer.
* S p rin g c lo s e s wh e n d e te c to r h e a d is re m o v e d fro m m o u n tin g b a s e . Th e in s ta lle d h e a d o p e n s th e s p rin g , b u t in te rn a lly
p ro v id e s a s h o rt c irc u it b e twe e n th e two te rm in a ls .
S h o rtin g J u m p e r*
S h o rtin g J u m p e r*
