Altronix AL842ADA220 NAC Power Extender
Overview
The Altronix AL842ADA220 is a cost-effective voltage-regulated NAC (Notification Appliance Circuit) power extender engineered for fire alarm system expansion. Designed to connect directly to any 24-volt Fire Alarm Control Panel (FACP), the AL842ADA220 delivers synchronized notification appliance control while maintaining loop supervision and fault detection across distributed circuits. The unit supports both Class A and Class B supervised notification circuits, enabling ADA-compliant audible-visual synchronization across multiple appliance types without adding burden to the primary FACP.
Key Features
- Dual FACP Inputs: Two (2) Class A Style Z or two (2) Class B Style W/X/Y input options, with two (2) NC dry contact trigger inputs for flexible integration with existing fire panels
- 8A Maximum Output Current: Supports up to 8A total alarm current across four programmable supervised output circuits, with per-output current limitation of 2.5A maximum
- Four (4) Programmable Output Circuits: Configure as four Class B Style W/X/Y outputs, four Class A Style Z outputs, or mixed two Class A and two Class B for circuit topology flexibility
- 2-Wire Horn/Strobe Sync Mode: Enables independent control of horns and strobes, allowing audible appliances to silence while visual notification continues—compliant with ADA accessibility requirements
- Multi-Protocol Sync Support: Compatible with Potter/Amseco, Faraday, Gentex, System Sensor, and CooperWheelock sync protocols, plus Temporal Code 3 and Steady Mode operation
- Input to Output Follower Mode: Synchronizes output circuit operation with selected input to maintain consistent appliance behavior across distributed circuits
- Dual Auxiliary Outputs: Two 1A auxiliary outputs (1A continuous, 1A AC disconnect rating) for independent accessory power and signaling
- 24VDC Class 2 Power-Limited Outputs: Regulated and filtered 24VDC supply maintains output loop supervision steered to input 1 or input 2 selection
- Signal Circuit Trouble Memory: Captures intermittent loop faults with programmable trouble indication for maintenance diagnostics
- Built-In Fault Protection: Thermal and short-circuit protection with automatic reset; ground fault detection on supervised circuits
- Common Trouble Input/Output: Centralized trouble signal tie-in for network-wide supervision reporting to FACP or external monitoring
- Battery Backup Ready: Enclosure accommodates two (2) 12VDC/18AH sealed lead acid or gel-type batteries for extended NAC operation during mains failure
Integration and Compatibility
The AL842ADA220 connects seamlessly to any 24-volt FACP and supports standard fire alarm panel protocols. Input voltage operates across a working range of 198VAC to 256VAC at 50/60 Hz with 2.5A input rating, accommodating variable mains conditions in commercial installations. Output loop supervision can be steered to either input to match FACP supervision topology, and the common trouble input/output permits direct integration with panel trouble monitoring circuits. The unit's programmable output configuration allows custom circuit assignment without physical rewiring, streamlining deployment in retrofit and new construction applications.
Physical Specifications
Housed in an 18" × 14.5" × 4.625" (H × W × D) steel enclosure, the AL842ADA220 mounts in standard control room racks or wall-mount locations common to fire alarm installations. The enclosure depth accommodates battery pack integration without external projection. Shipping dimensions are 21.75" × 18.25" × 5.75".
Ted PerryPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
I've specified the Altronix AL842ADA220 on multiple NAC expansion projects where primary FACP capacity was constrained. This extender eliminates the cost and complexity of upgrading to a larger control panel by distributing circuit loads across supervised outputs with proper fault isolation. The dual-input design and output follower mode ensure reliable synchronization even when appliances are geographically dispersed.
Technical Highlights:
- Supervised Output Distribution: Loop supervision on all four circuits with trouble memory prevents silent failures in distributed NAC architectures.
- ADA Sync Flexibility: The 2-wire horn/strobe mode and multi-protocol support allow compliance with accessibility rules without custom engineering.
- Battery Integration: On-board charging and accommodation for 12VDC/18AH batteries enables standalone NAC operation during power loss—critical for life safety circuits.
Deployment Considerations:
- Verify FACP input compatibility (Class A or B) before ordering to match panel topology.
- Plan output circuit assignment during design phase to leverage the programmable mixed-mode configuration and reduce future reconfiguration.
- If battery backup is required, budget for gel-type sealed lead acid batteries and a dedicated charging power supply; the AL842ADA220 provides only the connection and charging infrastructure.
The AL842ADA220 delivers reliable, code-compliant NAC expansion for mid-scale and distributed fire alarm systems. Thermal protection and ground fault detection reduce field service callbacks, and the integrated trouble memory supports proactive maintenance. Recommended for integrators managing multi-building campuses and retrofit projects where FACP capacity is the limiting factor.
