4-Wire Smoke Detector Connections - Fire-Lite Alarms MS-4424 Manual

3.3

4-Wire Smoke Detector Connections

Refer to the Device Compatibility Chart for suitable 4-wire smoke detectors.
TB1
1 2
A maximum of 200mA is available from the
+24VDC 4-wire smoke detector power cir-
cuit on TB1 terminals 3 and 4. Any power that
is drawn from the +24VDC Non-Resettable
Power on TB2 terminals 1 and 2 must be
subtracted from available 4-wire detector
power. (see Sections "Specifications" and
"Power" ).
Figure 3.3-1: Diagram of Connections for a 4-Wire Smoke Detector
Notes on Style B and Style D field wiring:
1) The Power Supervision Relay coil leads must be connected to the last detector base 24V screw terminals.
2) Calculation of the maximum allowable resistance in the 24VDC detector power wiring:
Where:
R
MAX
V
OM
N is the total number of detectors on the 24V supply loop.
I
S
N
A
I
S
I
R
16
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+ -
3 4
+24VR
R
MAX
is the maximum resistance of the 24V wires.
is the minimum operating voltage of the detector or end-of-line relay, whichever is greater, in volts.
is the detector current in standby.
is the number of detectors on the 24V power loop which must function at the same time in alarm.
is the detector current in alarm.
is the end-of-line relay current.
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24 VDC (+)
Common (-)
IDC(+)
IDC(-)
UL-listed 24 VDC
Four-Wire Smoke Detectors
TB4
Style B Initiating Device Circuit
Initiating Device Circuits 1, 2, 3, or 4
can be used. Style D wiring can also be
employed.
= (20.6 - V )
OM
(N x I ) + (N x I ) + (I
S A A R
MS-4424 15153:F1 06/18/97
24 VDC (+)
Red
Common (-)
Black
IDC(+)
IDC(-)
UL Listed
4.7K, 1/2-Watt
ELR
Supervision
B+ A+ A- B-
1 2 3 4
IDC #1
)
Listed
Power
Relay