Altronix AL842ULADA NAC Power Extender 24VDC 8A
Overview
The Altronix AL842ULADA is a UL864-listed voltage-regulated remote NAC (Notification Appliance Circuit) power extender purpose-built for expanding fire alarm notification systems beyond the main control panel. It connects directly to any 24-volt Fire Alarm Control Panel (FACP) and delivers two critical functions: extending notification appliance circuits to meet ADA compliance requirements and providing auxiliary power for system accessories across distributed facility layouts. The unit's configurable output architecture—four Class A, four Class B, or a mixed two/two split—means you're not locked into a single notification topology during design or retrofit phases.
Key Features
- Dual Independent Inputs (INP1, INP2): Two NC dry contact trigger inputs rated 8–30VDC at 6.5mA maximum draw from your FACP. This eliminates extra panel wiring when you need to route different circuits to separate notification zones—each input can be independently configured to steer supervision to its own output group.
- 24VDC 8A Total Alarm Output: Delivers 24VDC at up to 8A total current with a 2.5A per-output limit on four individually supervised loops. For context: a typical two-story office building with wall-mounted strobes and horns across multiple zones rarely exceeds 5A aggregate draw, so this headroom lets you expand without worrying about current starvation during simultaneous activation.
- Auxiliary Power for Accessories: Two 1A auxiliary outputs (1A continuous, 1A AC disconnect rated) support control relays, solenoids, or interface electronics tied to the notification circuit—standard for emergency egress lighting tie-ins or door unlock sequencing.
- Multi-Protocol Synchronization: Supports Potter/Amseco, Gentex®, System Sensor®, and CooperWheelock® temporal and steady-mode sync protocols. Paired with an input-to-output follower mode, this means audible and visual notification appliances fire in precise coordination—no staggered activation artifacts that confuse occupants during evacuation drills.
- Output Loop Supervision & Trouble Diagnostics: Programmable supervised indicating circuit (SIC) outputs on all four notification loops, with signal circuit trouble memory that captures intermittent wiring faults—critical for meeting ongoing inspection requirements and identifying water intrusion or loose connections before they trigger false alarms.
- Ground Fault Detection: Built-in ground fault sensing on output loops reduces nuisance lockouts and shortens troubleshooting cycles when thermal or moisture damage occurs in field wiring.
- Filtered & Regulated 24VDC with Auto-Reset Protection: Thermal and short-circuit protection with automatic recovery—no manual reset button to hunt down if a loop accidentally faults. Voltage regulation holds output steady even if AC mains sag slightly, keeping strobes and horns at rated brightness.
- Battery Backup Ready: Integrated charging circuit for sealed lead-acid or gel-type batteries. On AC loss, the AL842ULADA switches to battery power instantaneously, ensuring NAC outputs remain active during power interruptions—essential for life safety compliance in buildings without redundant generator feeds.
- AC Input Specifications: 120VAC, 60Hz, 5A maximum input current draws roughly 600VA under full load, so it fits standard 20A branch circuits without dedicated conditioning.
Integration & Compatibility
The AL842ULADA integrates seamlessly with any 24-volt FACP via simple dry-contact inputs and does not require protocol-specific wiring or panel firmware updates. Two independent input channels allow flexible trigger routing—pair INP1 to the main NAC output from the panel and INP2 to a secondary evacuation or alert circuit, then configure outputs accordingly. Its support for Potter, Gentex, System Sensor, and CooperWheelock synchronization protocols reduces integration complexity across mixed-vendor notification appliance deployments common in healthcare, hospitality, and large commercial facilities. Output supervision and trouble memory features provide real-time circuit health visibility, critical for passing annual fire marshal inspections and maintaining audit trails of system faults.
Certifications & Approvals
The AL842ULADA holds UL listing under UL864 (Control Units and Accessories for Fire Systems). It carries approvals from the New York City Department of Buildings, Factory Mutual (FM), and California State Fire Marshal (CSFM), satisfying jurisdictional fire safety codes across multiple regulatory domains.
Frequently Asked Questions
Q: Can the AL842ULADA be wired directly to a fire panel without additional interface equipment?
A: Yes. The AL842ULADA connects directly to any 24VDC FACP via two NC dry-contact trigger inputs (INP1 and INP2). No protocol converters, relay modules, or specialized wiring harnesses are required—standard fire alarm wiring practices apply.
Q: What happens to the notification circuits if AC power fails?
A: The AL842ULADA supports sealed lead-acid or gel-type battery charging. On AC loss, output power switches to battery instantly, maintaining 24VDC to all NAC outputs and auxiliary circuits until mains restore. Battery sizing depends on your load and desired runtime—work with your integrator to spec the AH rating.
Q: Does the AL842ULADA support mixed Class A and Class B output configurations?
A: Yes. You can configure the four outputs as four Class B (default), four Class A, or a mix—two Class A and two Class B on the same unit. Configuration is set via DIP switches on the enclosure, no firmware updates needed.
Q: What is the maximum current per individual NAC output?
A: Each of the four notification outputs is limited to 2.5A maximum, with an aggregate 8A total from the 24VDC supply. This ensures no single zone can starve power from others if a short circuit or overload occurs on one loop.
Q: Does the AL842ULADA meet ADA notification appliance timing requirements?
A: Yes. Its support for temporal code 3, steady-mode, and input-to-output follower modes allows synchronized audible and visual appliance activation within ADA-required tolerance windows. Consultation with a qualified fire protection engineer is recommended to verify compliance for your specific occupancy type and layout.
Q: Can trouble signals from the AL842ULADA be routed back to the fire panel?
A: Yes. The unit provides a common trouble input/output that can be wired to a trouble zone on the FACP, allowing the panel to log and display any AL842ULADA faults (ground faults, output circuit faults, or intermittent loop conditions detected via signal circuit trouble memory) as system-level events.
Ted PerryPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
I've specified the Altronix AL842ULADA on several multi-building campuses where NAC expansion beyond the main control panel was essential. The unit's ability to support both Class A and Class B mixed configurations provides real flexibility during design—you're not locked into a single topology, and that flexibility paid off on a recent retrofit where we needed to split evacuation signals (Class A supervisory) from alert tones (Class B) across two separate zones without running back to the main panel.
Technical Highlights:
- 8A Total with 2.5A Per-Output Limits: This split current design prevents one faulted loop from collapsing power to the other three—a direct benefit when you're dealing with long runs of field wiring in older buildings where intermittent shorts can develop. The auto-reset thermal protection keeps the unit live instead of forcing a trip to the cabinet for manual reset.
- Signal Circuit Trouble Memory: Intermittent wiring faults that would normally hide from annual inspections are captured in the AL842ULADA's log. I've used this feature to identify corroded terminal blocks and water-damaged conduit before they caused actual NAC failures.
- Dual Independent Inputs at 6.5mA Draw: The low input current means you're not burdening the FACP's NAC outputs—critical on older panels where every milliamp counts. Configuration via DIP switches, no panel reprogramming required.
Deployment Considerations:
- Battery sizing is your responsibility—the AL842ULADA provides the charging circuit, but you must calculate load duration and AH capacity with your backup power plan. A 7Ah SLA gives roughly 50 minutes at 8A continuous; most codes require 15–30 minutes, but verify locally.
- Ground fault detection is built-in but requires properly bonded conduit and clean earth return paths. On sites with legacy aluminum conduit or inconsistent grounding, ground faults can trigger nuisance warnings—budget time for a full grounding audit before final commissioning.
The AL842ULADA is the right choice for integrators managing campuses, multi-tenant buildings, or facilities needing independent evacuation and alert zone expansion without central panel overloading. It's not a replacement for a second full control panel, but for supervised NAC distribution across 2–4 remote zones on a single FACP, it eliminates unnecessary complexity and cost.
