System Sensor SpectrAlert S1224MCK Installation And Maintenance Instructions page 2

Typical wire size resistance:
18 AWG solid: Approximately 8 ohms/1,000 ft.
16 AWG solid: Approximately 5 ohms/1,000 ft.
14 AWG solid: Approximately 3 ohms/1,000 ft.
12 AWG solid: Approximately 2 ohms/1,000 ft.
Example: Assume you have 10 devices on a zone and each re-
quires 50 mA average and 2000 Ft. of 14 AWG wiring (total
length=outgoing +return). The voltage at the end of the loop is
0.050 amps per device x 10 devices x 3 ohms/1,000 ft. x 2000 ft
=3 volts drop.
NOTE: If class "A" wiring is installed, the wire length may be up
to 4 times the single wire length in this calculation.
The same number of devices using 12 AWG wire will produce only
2 volts drop. The same devices using 18 AWG wire will produce
8 volts drop. Consult your panel manufacturer's specifications, as
well as SpectrAlert's operating voltage range to determine accept-
able voltage drop.
Figure 1A: Current Draw Measurements (RMS)
NOTE: All 'S' and 'P' models were only tested at the 8-17.5 and
16-33 Volt-FWR/DC limits. This does not include the 80% low-
end or 110% high-end voltage limits.
Strobe Current Draw
Operating
Current
Strobe
Candela
Setting 12V
15
112
15/75
135
30
75
110
NOTE: 12 VDC 2-wire horn/strobe current is shown in Figure 1D.
24VDC 2-wire horn/strobe current draw is shown in Figure 1E.
Horn/Strobe current draw can be calculated by adding the strobe
current draw (Figure 1A) for chosen candela setting to the horn
current draw (Figure 1C) for chosen setting.
Figure 1B: Horn Sound Measurements (dBA):
Selectable Horn Tones
Temporal
Low Electromechanical
Volume
3000 Hz Interrupted
High Electromechanical
Volume
3000 Hz Interrupted
Non- Low Electromechanical
Temporal Volume
3000 Hz Interrupted
High Electromechanical
Volume
3000 Hz Interrupted
D900-37-00
FWR DC
Operating
Current
Strobe
24V 12V 24V
64 127 59
74 127 69
93 90
158 160
208 209
8-17.5V 16-33V
67 75
68 75
71 80
72 81
71 79
72 79
76 84
77 86
firealarmresources.com
Figure 1C: Horn Current Draw Measurements (RMS):
Selectable Horn Tones
Temporal
Low Electromechanical
Volume
3000 Hz Interrupted
High Electromechanical
Volume
3000 Hz Interrupted
Non- Low Electromechanical
Temporal Volume
3000 Hz Interrupted
High Electromechanical
Volume
3000 Hz Interrupted
NOTE: Regulated 12 VDC, max operating current 44.4 mA
Regulated 24 VDC, max operating current 57.0 mA
12 V FWR, max operating current 45.7 mA
24 V FWR, max operating current 57.5 mA
Figure 1D: 12VDC Horn/Strobe Current Draw
Measurements (mA RMS)
Low Volume
Candela
Electromechanical
Setting
15 111
15/75 127
15 113
15/75 128
Figure 1E: 24VDC Horn/Strobe Current Draw
Measurements (mA RMS)
Low Volume
Candela
Electromechanical
Setting
15 71
15/75 86
30 99
75 166
110 209
15 74
15/75 86
30 101
75 167
110 213
Candela equivalent at –40°C and below:
15cd
15/75cd
30cd
75cd
110cd
2
DC FWR
12V 24V 12V
15 23 13
15 33 13
36 53 20
43 57 21
16 37 19
16 32 18
38 49 46
44 56 42
Temporal
High Volume
3000 Hz Electromechanical 3000 Hz
111 112 112
127 126 129
Non-Temporal
112 114 115
128 130 134
Temporal
High Volume
3000 Hz Electromechanical 3000 Hz
70 73
85 87
98 100
166 167
209 210
Non-Temporal
74 79
88 93
101 107
167 173
213 218
3cd
20cd
9cd
27cd
46cd
I56-2257-005R
24V
23
23
44
40
29
33
49
58
75
88
100
170
213
82
96
110
176
222