Two Class B initiating device circuits.
One Class B notification appliance circuit.
Synchronization for System Sensor®, Gentex® and Wheelock® devices.
Silent or audible walk test operation.
Disable switches provided per zone.
Form C alarm and trouble relays.
The two zone SK-2 is a 24 VDC
FACP that provides two Class B
initiating device circuits and one Class
B notification appliance circuit (NAC).
The SK-2 NAC protocol includes the
ability to silence audible devices while
strobes continue to flash, using only a
single pair of wires. The SK-2 is also
compatible with conventional input
devices such as two- and four-wire
smoke detectors, pull stations,
waterflow devices, tamper switches and
other normally-open contact devices.
Activation of a compatible smoke
detector or any normally-open fire
alarm initiating device activates audible
and visual signaling devices, illuminates
an indicating LED, sounds the piezo
sounder at the FACP, activates the
FACP alarm relay, and operates an
optional module used to notify a remote
station or initiate an auxiliary control
The SK-2 is compatible with System
Sensor® I3 detectors providing
advanced features such as drift
compensation, maintenance alert, and
freeze warning. Automatic
synchronization of audio/visual devices
is provided, using three selections for
• Two Style B (Class B) initiating
device circuits (IDCs)
• One Style Y (Class B) notification
appliance circuit (NAC)
• Support for synchronization of
standard ANSI audible signals and
ADA compliant strobes per NFPA 72
• Selectable for System Sensor,
Wheelock, and Gentex protocols
• Selective silence feature allows
manual silence of horns while strobes
continue to flash on the same NAC
• Silent or audible walk test operation
• Alarm verification selectable per zone
• Program each zone for supervisory or
fire with separate red and yellow
• Disable switches provided per zone
• Program NACS for
– Silence inhibit
– Auto silence
– Strobe synchronization
– Temporal or steady signal
– Silenceable or nonsilenceable
• Form C alarm and trouble relays
• 3A total usable current
• Optional dress panel (PN SK-DP2/4).
SK-2 Primary AC: 120 VAC @ 50/60
Wiring: 14 AWG (2.0 mm2) with 600 V
Initiating Device Circuits (IDCs)
Operating Voltage: 22 VDC nominal;
Standby Current: 4 mA.
Alarm Current: 15 mA min.
Short-circuit Current: 40 mA max.
Loop Resistance: 100 max.
EOL Resistor: 4.7K , 1/2 watt.
2.5A @ 24 VDC with standard
Signaling Current: 2.5A max with
EOL Resistor: 4.7K , 1/2 watt
Form C Relays
Types: Trouble and alarm
Contact Ratings: 2A @ 30 VAC,
Operating Voltage: 24 VDC nominal
Current: 500 mA max, power-limited