The Siemens PAD-3 is a notification appliance circuit (NAC) extender with built-in 24 VDC auxiliary power output. Specifically, it expands the notification capacity of a Siemens fire alarm system by adding four supervised NACs and an auxiliary 24 VDC bus. As a result, large or distributed buildings can drive more horns, strobes, and door holders than a single panel could power on its own.
In addition, the PAD-3 part number 599-699189 corresponds to the black-enclosure variant. A red-enclosure variant is also available for matching red-cabinet installations.
How the Siemens PAD-3 Works
First, the host fire alarm panel signals the PAD-3 through one or two input lines. Then, the PAD-3 drives its four output NACs from its own internal power supply. Therefore, the notification load is offloaded from the host panel.
Furthermore, the PAD-3 supports flexible output programming. Specifically, outputs can be configured as:
- Steady (continuous on)
- ANSI temporal pattern (T3 fire signaling)
- Synchronized strobe (typically 1 Hz)
In addition, the auxiliary power output is suitable for door holders, alternative signaling devices, or other 24 VDC loads up to its rated current.
Specifications
- Function: NAC extender with auxiliary 24 VDC output
- Siemens part number: 599-699189 (black enclosure)
- Total NAC output: 6 A at 24 VDC
- NACs: 4, each rated 3 A power-limited
- Auxiliary output: 3 A at 24 VDC, power-limited
- Inputs: 1 or 2 control inputs from host panel
- Output modes: Steady / ANSI temporal / synchronized strobe
- Dimensions: 12.2″ × 16.4″ × 3.1″
- Color: Black (red variant available)
Compatible Siemens Fire Alarm Systems
The PAD-3 is designed for Siemens Fire Safety 24 VDC notification appliances. Examples include the Siemens ZH series horns and ZR strobes, plus other Siemens-approved 24 VDC devices. However, before mixing brands on a NAC, always verify the appliance’s compatibility with the PAD-3’s synchronization protocol.
Typical Applications
- Adding NACs in large commercial buildings beyond panel capacity
- Powering remote notification zones in distributed buildings
- Driving door holders alongside notification appliances
- Synchronizing strobes across multiple zones in line-of-sight spaces
Order the Siemens PAD-3
Life Safety Consultants stocks the Siemens PAD-3 in both enclosure colors. To verify input wiring or auxiliary load planning, call 1-888-557-0558. Alternatively, email sales@lifesafetycom.com.
For more information, contact the Life Safety Consultants team at (888) 557-0558, or email us at: sales@lifesafetycom.com
Additional information
| Weight | 10 lbs |
|---|---|
| Dimensions | 12 × 14 × 6 in |
| Condition | New |
| Part Type | Appliance Extender, Power Extender Panel, Power Supply |
| Manufacturers | Siemens |
| Compatible Panels | MXL, FireFinder, Sinteso, Cerberus PRO |
| Cross Reference | PAD-3 |
| Specification | Part # 500-596450 series |







