Altronix AL300ULM 12/24VDC 2.5A UL-Listed Power Supply with Supervised Outputs

Overview

The Altronix AL300ULM is a UL-listed, 12/24VDC linear power supply built for commercial access control and security panel installations where compliance, supervision, and battery standby are non-negotiable. Rated at 2.5A continuous output and approved by UL, cUL, and MEA, the AL300ULM fits the compliance requirements of most AHJ-driven commercial projects without added documentation gymnastics. Five independent outputs give integrators the flexibility to power readers, locks, request-to-exit devices, and ancillary sensors from a single enclosure — a real time-saver on medium-density door controllers.

If you are evaluating Altronix power supplies for a supervised access control installation, the AL300ULM is the unit to benchmark first in this output-current range. For broader context on matching power supply capacity to door count and lock type, the security power supplies category page covers the full line.

Key Features

• Selectable 12VDC or 24VDC Output: Flip between 12VDC and 24VDC to match the lock or reader voltage without sourcing a second power supply — critical when a spec change arrives after rough-in and you cannot swap the enclosure.
• 2.5A Continuous Output: At 2.5A, this unit comfortably powers multiple electromagnetic locks (typically 250–500mA each at 12VDC) or a mix of card readers and strikes on a single panel run. Size the load budget conservatively — leave 20–25% headroom for inrush.
• Five Independently Fused Outputs: Five discrete output terminals mean you can circuit-protect each load independently. A shorted lock or failed reader trips only that output, not the entire panel — the kind of fault isolation that keeps a six-door system running on five doors instead of going completely dark.
• Dual 12VDC/7AH Battery Standby: Two 7AH sealed lead-acid batteries provide standby capacity sized for extended outages. At a 1A average draw, that is roughly 14 amp-hours of reserve — calculate your actual standby hours against your load profile for AHJ submittal. Battery compartment is integrated into the enclosure.
• Form C AC Fail Supervision: The Form C relay output for AC failure lets your panel or monitoring receiver detect a mains loss event and log it as a discrete zone — meeting the UL supervision requirements common on commercial intrusion and access panels without external relay modules.
• Form C Low Battery Supervision: Separate Form C relay for low battery condition means you get advance warning before standby capacity is exhausted. On monitored systems this closes the loop between power plant health and central station reporting.
• Form C Battery Presence Supervision: Detects a missing or disconnected battery — important on inspected systems where battery theft or omission during service visits is an audit liability.
• Form C Power Fail Supervision: A fourth supervised relay covers overall power failure, giving integrators or monitoring stations a consolidated fault point distinct from AC fail — supports panel designs that need to differentiate between partial and total power loss events.
• UL / cUL / MEA Agency Approvals: Triple-listed for UL, cUL, and MEA. MEA approval matters specifically for New York City installations, where non-MEA power supplies are routinely rejected at inspection. If you are doing NYC commercial work, this listing removes a common RFI hurdle.
• 1A @ 28VDC Output Relay Rating: The supervised relay contacts are rated 1A at 28VDC — adequate for most panel auxiliary input circuits but not for directly switching lock current. Wire relay outputs to panel input zones, not directly to locking hardware.
• 13"H x 13.5"W x 3.25"D Enclosure: The metal enclosure is sized to house both the power supply board and the two 7AH batteries internally. At 3.25" depth, it mounts flush against most backbox depths in telecom closets and IDF rooms without protruding into walkway clearances.
• 115VAC / 60Hz Input: Standard North American mains input — no step-down transformer or special circuit required. Wire directly to a dedicated 15A breaker per standard low-voltage installation practice.

Integration & Compatibility

The AL300ULM is designed to integrate with UL-listed access control systems and intrusion panels that require supervised auxiliary power. The four Form C supervision relays map directly to standard panel zone inputs — wire each relay to a dedicated zone on your controller to enable remote fault reporting through your VMS or central station receiver. The selectable 12/24VDC output makes the unit compatible with the majority of North American electromagnetic locks, electric strikes, and card readers without additional voltage conversion.

For installations requiring higher current capacity on individual outputs or a greater number of independently controlled doors, consider pairing this unit with an Altronix relay expander or stepping up within the Altronix access power line to a higher-amperage model. If your project includes PoE-powered readers or IP access control panels, cross-reference the per-reader PoE budget against the AL300ULM's 2.5A output — PoE readers typically draw 200–400mA at 12VDC equivalent, so the five-output structure fits neatly into a four-to-six reader zone.

Integrators running network video recorders alongside access control panels will find the AL300ULM useful as a dedicated access power source, keeping door hardware on a separate supervised power circuit from cameras and network gear — a clean separation that simplifies fault tracing and AHJ sign-off.

Frequently Asked Questions

Q: What is the difference between the AL300ULM's AC Fail and Power Fail supervision outputs?

A: AC Fail supervision (Form C) signals loss of mains voltage specifically, while Power Fail supervision (also Form C) indicates an overall power failure condition. Running both to separate panel zones lets you distinguish between a utility outage (AC Fail) and a broader failure of the supply itself — useful for monitoring and for AHJ-required supervision documentation.

Q: Can I run the AL300ULM at 24VDC for electric strikes and 12VDC for card readers at the same time?

A: No. The AL300ULM is a single-voltage output supply — you select either 12VDC or 24VDC, not both simultaneously. If your installation requires mixed voltages, you will need a separate power supply for each voltage rail or a multi-voltage access power unit.

Q: What battery size does the AL300ULM require, and does it fit inside the enclosure?

A: The AL300ULM accepts two 12VDC/7AH sealed lead-acid batteries, which are housed inside the unit's 13"H x 13.5"W x 3.25"D metal enclosure. Batteries are not included and must be sourced separately — 7AH/12V SLA batteries are a standard form factor available from multiple suppliers.

Q: Is the AL300ULM approved for New York City installations?

A: Yes. The AL300ULM carries MEA approval in addition to UL and cUL listings, which satisfies the New York City Department of Buildings’ MEA requirement for commercial security power supplies.

Q: What is the output relay contact rating on the AL300ULM supervision outputs?

A: Each Form C supervision relay is rated 1A at 28VDC. These contacts are suitable for wiring to panel zone inputs for monitoring — they are not rated to directly switch lock or strike current, which typically requires a separate relay module rated for the lock's inrush current.

Q: Does the AL300ULM include supervision for a missing or disconnected battery?

A: Yes. Battery Presence Supervision via a dedicated Form C relay detects if the battery is absent or disconnected, not just low or failed. This is particularly relevant for inspected commercial systems where battery removal during service is a documented audit risk.

Eden Phillips

The AL300ULM is one of those workhorses I spec on virtually every mid-size commercial access control job where the AHJ is going to scrutinize the power plant. The four independent Form C supervision relays — covering AC fail, low battery, battery presence, and power fail — are not features you often see fully implemented at this price point in a single UL/cUL/MEA-listed package. That MEA listing alone saves an RFI and a re-inspection on any NYC project.

Technical Highlights:

• Quad Form C Supervision: Four discrete Form C relays (AC Fail, Low Battery, Battery Presence, Power Fail) each wire to a separate panel zone — you get granular fault data at the monitoring station without adding relay modules or eating into your panel's zone count with workarounds.
• Dual 7AH Battery Capacity: Two 12VDC/7AH batteries internally housed give you 14AH total reserve. At a 500mA average load (two mag-locks plus readers), that is over 20 hours of standby — enough to cover most commercial outage windows without a generator handoff.
• Five-Output Structure: Five independently fused outputs at 2.5A total means fault isolation per circuit. One shorted strike does not kill the door controller or adjacent locks — an important operational resilience point for any system running card-based egress on life-safety paths.

Deployment Considerations:

• The relay contacts are rated 1A at 28VDC — wire supervision relays to panel zone inputs only; never route lock current through them directly, or you will burn a contact on the first mag-lock inrush cycle.
• Batteries are not included. Budget for two 12VDC/7AH SLA units per installation. Confirm the battery form factor fits the 3.25"-deep enclosure before ordering oversized batteries from a non-standard supplier.

Deploy the AL300ULM on commercial office or retail multi-door access control projects — particularly where MEA compliance, battery standby documentation, and per-circuit fault reporting are on the AHJ checklist. It is purpose-built for exactly that job.