20
Field Wiring Power Supply Connections
Note that the S/FDACT requires an external power source. The S/FDACT may derive power from the
monitored FACP’s non-resettable, auxiliary power output circuits if compatible, or from separate power
supplies complying with the
Standard for Power Supplies for Fire Protective Signaling Systems
,
UL 1481.
The S/FDACT requires 20.4-27.5 VDC filtered (24 VDC nominal), and the maximum load is 200 mA.
To determine if the FACP’s aux. power output is compatible, the voltage must be non-resettable, within
the 20.4-27.5 VDC range, and the available DC current must be rated sufficiently to provide power to the
S/FDACT and any other auxiliary devices sharing the aux. power circuit. Also, the installer must include
the S/FDACT load current in the FACP’s battery calculations.
Connect the 24 VDC supply making sure to observe the correct polarity.
Connect the positive lead to terminal 15.
Connect the return lead (Common) to terminal 16.
Caution
: reversing the polarity for long periods of time can damage both the unit and the power source.
The S/FDACT is protected by a diode in series with the power input terminal.
Use #18 wire minimum for all power supply wiring. The terminals will accept wire sizes up to #16.
IMPORTANT:
Connect terminal 17 to a metallic cold-water-pipe, driven ground rod, or other
proper earth ground. Transient voltage suppression devices protecting the telephone lines and
power supply circuits are intended to shunt excess energy caused by nearby lightning strikes or
other electrical surges directly to earth ground. These devices cannot function properly without a
solid earth ground connection on terminal 17.
