Wire Sizes

The designer must be sure that the last device on the circuit has sufficient voltage to operate the device within its rated voltage. When calculating the voltage available to the last device, it is nec- essary to consider the voltage drop due to the resistance of the wire. The thicker the wire, the less the voltage drop. Generally, for purposes of determining the wire size necessary for the system, it is best to consider all of the devices as “lumped” on the end of the supply circuit (simulates “worst case”).

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

 

FWR

DC

 

Operating

Operating

 

Current

Current

Candela

Strobe

Strobe

 

 

Setting

12V 24V

12V 24V

15112 64 127 59

15/75

135

74

127

69

30

 

93

 

90

75

 

158

 

160

110

 

208

 

209

Figure 1B: Horn Sound Measurements (dBA):

Selectable Horn Tones

8-17.5V

16-33V

 

 

 

 

 

Temporal

Low

Electromechanical

67

75

 

Volume

 

 

 

 

3000 Hz Interrupted

68

75

 

 

 

 

 

 

 

 

High

Electromechanical

71

80

 

Volume

 

 

 

 

3000 Hz Interrupted

72

81

 

 

 

 

 

 

 

Non-

Low

Electromechanical

71

79

Temporal

Volume

 

 

 

3000 Hz Interrupted

72

79

 

 

 

 

 

 

 

 

High

Electromechanical

76

84

 

Volume

 

 

 

 

3000 Hz Interrupted

77

86

 

 

 

 

 

 

 

Figure 1C: Horn Current Draw Measurements (RMS):

 

 

 

 

DC

 

FWR

Selectable Horn Tones

 

 

 

 

 

 

12V

 

24V

12V

 

24V

Temporal

Low

Electromechanical

15

 

23

13

 

23

 

Volume

 

 

 

 

 

 

 

 

3000 Hz Interrupted

15

 

33

13

 

23

 

 

 

 

 

 

 

 

 

 

 

 

 

 

High

Electromechanical

36

 

53

20

 

44

 

Volume

 

 

 

 

 

 

 

 

3000 Hz Interrupted

43

 

57

21

 

40

 

 

 

 

 

 

 

 

 

 

 

 

 

Non-

Low

Electromechanical

16

 

37

19

 

29

Temporal

Volume

 

 

 

 

 

 

 

3000 Hz Interrupted

16

 

32

18

 

33

 

 

 

 

 

 

 

 

 

 

 

 

 

 

High

Electromechanical

38

 

49

46

 

49

 

Volume

 

 

 

 

 

 

 

 

3000 Hz Interrupted

44

 

56

42

 

58

 

 

 

 

 

 

 

 

 

 

 

 

 

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

NOTE: 12VDC 2-wire horn/strobe current is shown in Figure 1D. 24VDC 2-wire horn/strobe current is shown in Figure 1E. Current draw for other horn/strobe power supplies can be calculated by adding the strobe current draw (Figure 1A) for chosen candela set- ting to the horn current draw (Figure 1C) for chosen setting.

Figure 1D: 12VDC Horn/Strobe Current Draw Measurements (mA RMS)

 

 

 

Temporal

 

 

 

 

 

 

 

 

 

Low Volume

 

High Volume

 

 

 

 

 

 

 

 

Candela

Electromechanical

 

3000 Hz

Electromechanical

 

3000 Hz

Setting

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

15

111

 

111

112

 

112

 

 

 

 

 

 

 

15/75

127

 

127

126

 

129

 

 

 

 

 

 

 

 

 

 

Non-Temporal

 

 

 

 

 

 

 

 

15

113

 

112

114

 

115

 

 

 

 

 

 

 

15/75

128

 

128

130

 

134

 

 

 

 

 

 

 

Figure 1E: 24VDC Horn/Strobe Current Draw Measurements (mA RMS)

 

 

 

Temporal

 

 

 

 

 

 

 

 

 

Low Volume

 

High Volume

 

 

 

 

 

 

 

 

Candela

Electromechanical

 

3000 Hz

Electromechanical

 

3000 Hz

Setting

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

15

71

 

70

73

 

75

 

 

 

 

 

 

 

15/75

86

 

85

87

 

88

 

 

 

 

 

 

 

30

99

 

98

100

 

100

 

 

 

 

 

 

 

75

166

 

166

167

 

170

 

 

 

 

 

 

 

110

209

 

209

210

 

213

 

 

 

 

 

 

 

 

 

 

Non-Temporal

 

 

 

 

 

 

 

 

15

74

 

74

79

 

82

 

 

 

 

 

 

 

15/75

86

 

88

93

 

96

 

 

 

 

 

 

 

30

101

 

101

107

 

110

 

 

 

 

 

 

 

75

167

 

167

173

 

176

 

 

 

 

 

 

 

110

213

 

213

218

 

222

 

 

 

 

 

 

 

D900-28-00

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I56-1796-011R

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System Sensor S1224MC specifications Wire Sizes, Current Draw Measurements RMS

S1224MC specifications

The System Sensor S1224MC is a highly advanced smoke detector designed for commercial and industrial applications. It offers an array of features and technologies that ensure effective fire detection and reliable performance in various environments. This product exemplifies System Sensor's commitment to innovation and safety, making it a popular choice among fire safety professionals.

One of the main features of the S1224MC is its intelligent optical sensing technology. This advanced sensing mechanism allows the detector to differentiate between false alarms and real fire conditions with remarkable accuracy. The optical sensor is particularly effective in detecting smoldering fires that produce larger particles, thus providing early warning and minimizing the risk of extensive damage.

The S1224MC also incorporates a unique dual-sensor design which enhances its detection capabilities. This design combines an optical sensor with a heat sensor, allowing for a broader range of fire types to be detected. The dual-sensor approach not only improves response times but also reduces the chances of nuisance alarms, a common issue in many environments.

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The S1224MC’s design emphasizes durability and robustness. Constructed from high-quality materials, it can withstand harsh environmental conditions, making it suitable for both indoor and outdoor applications. Furthermore, the unit has a long operational life, supported by low power consumption, thus minimizing maintenance costs.

In conclusion, the System Sensor S1224MC combines state-of-the-art features and technologies to provide reliable fire protection in a variety of environments. Its intelligent sensor technology, dual-sensor design, real-time monitoring capabilities, and compatibility with various systems make it an essential component of modern fire safety solutions. Whether for new installations or upgrades, the S1224MC stands out as a premier choice for professionals seeking reliability and performance in fire detection.