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3.3
4-Wire Smoke Detector Connections
Refer to the Device Compatibility Chart Document for suitable 4-wire smoke detectors.
TB2
A maximum of 200mA is available from the
voltage for 4-wire smoke detector power
circuit on terminals 3 and 4. Any power that
is drawn from the Non-Resettable Power on
terminals 5 and 6 must be subtracted from
available 4-wire detector power. (see Sec-
tions "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
I
S
N
A
I
S
I
R
16
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+
-
3
4
VR
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 total number of detectors on the 24V supply loop.
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.
MS-4412B/MS-4424B 15125:F1 06/24/97
firealarmresources.com
24 VDC (+)
Common (-)
IDC(+)
IDC(-)
UL-listed 24 VDC
Four-Wire Smoke Detectors
(12 VDC for the MS-4412B)
TB4
Style B Initiating Device Circuit
Initiating Device Circuits 1, 2, 3, or 4
can be used.
=
(20.6 - V
)
OM
(N x I
) + (N
x I
) + (I
)
S
A
A
R
24 VDC (+)
Red
Common (-)
Black
IDC(+)
IDC(-)
UL Listed
ELR
Supervision
B+
B-
7
8
IDC #1
Listed
Power
Relay
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