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Prerequisites for Installation
2.4 Electrical Specifications
2.4.1 Power Requirements
Voltage for the SK-FFT must be a power-limited, filtered, non resettable nominal 24 VDC source. The voltage source must be
within the range of 17-29 VDC.
2.4.2 Current Ratings
Maximum current ratings for determining backup battery requirements for alarm (active) and standby conditions over the
input voltage range of 17-29 VDC are shown in Table 2.2.
2.5 Wiring Specifications
Induced noise (transfer of electrical energy from one wire to another) can interfere with telephone communication or cause
false alarms. To avoid induced noise, follow these guidelines:
•
Isolate input wiring from high current output and power wiring. Do not pull one multi-conductor cable for the entire
panel. Instead, separate the wiring as follows:
•
Do not pull wires from different groups through the same conduit. If you must run them together, do so for as short a
distance as possible or use shielded cable. Twisted, shielded wire on the Audio Circuits is recommended for maximum
protection against EMI and AFI emissions and susceptibility. Connect the shield to earth ground at the panel. You must
route high and low voltages separately.
•
Route the wiring around the inside perimeter of the cabinet. It should not cross the circuit board where it could induce
noise into the sensitive microelectronics or pick up unwanted RF noise from the high speed circuits. See Figure 2.4 on
page 11 for an example.
•
High frequency noise, such as that produced by the inductive reactance of a speaker or bell, can also be reduced by
running the wire through ferrite shield beads or by wrapping it around a ferrite toroid.
2.6 Wire Routing
You must follow power-limited wiring techniques, which include maintaining one-quarter inch spacing between power-limited
and non-power limited circuits and separating high and low voltage circuits
10
Circuits
SLC Circuits
Audio Circuits
Table 2.1 Electrical Ratings
SK-FFT
FFT-24
Table 2.2 SK-FFT Current Draw
SLC loops
Relay circuit
Table 2.3 Wiring Specifications
Voltage
Current
17 MV
150 mA
18 V
53 mA
Active
Standby
230 mA
120 mA
25 mA
Audio circuits
Model SK-FFT Manual — P/N 54711:B2 12/18/2020
Electrical Specifications
10 mA
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