Altronix ACM4CBE 4-Output Access Power Controller
The Altronix ACM4CBE is a UL294-listed access power controller designed for multi-door installations that require independent output switching and fire alarm supervision. It converts a single 12–24 VAC or VDC input into four isolated Class 2 outputs, each rated for 2A continuous delivery to magnetic locks, electric strikes, and door holders. The ACM4CBE is built around fail-safe logic and FACP integration—every output can be individually disconnected by the fire alarm control panel during emergency egress events, eliminating the need for separate relay modules.
Key Features
- Four 2A Independently Controlled Outputs: PTC auto-resettable protection per line; individual outputs can be switched or supervised without affecting others. Supports up to 10A total draw across all four outputs.
- Class 2 Rated Power-Limited Design: UL294 and cUL certification ensures compliance with fire alarm and safety codes. No external relays required for Class 2 circuits.
- Fire Alarm Disconnect Per Output: FACP interface allows the fire alarm control panel to cut power to each output independently—critical for emergency egress and door unlock sequencing without powering down the entire system.
- Fail-Safe and Fail-Secure Modes: Selectable operation for magnetic locks (fail-safe on power loss) or strikes (fail-secure). Single unit supports mixed-mode installations.
- Open Collector or Dry Contact Inputs: Accepts trigger signals from access control readers, keypads, and controllers. No isolated 5V output required from upstream panels.
- Dual Power Input Option: Single common source or two isolated inputs—board power and lock power can originate from separate circuits to isolate control logic from high-current lock loads.
- Compact DIN-Rail or Surface Mount: 8.5″ H × 7.5″ W × 3.5″ D footprint fits standard electrical cabinets and utility boxes. Mounts directly to DIN rail or wall.
- PTC Auto-Reset Fusing: No blown fuses to replace on transient overload; protection resets automatically when the fault clears, reducing service callbacks on noisy installations.
The ACM4CBE is purpose-built for integrators deploying four or fewer doors under a single access control system with fire alarm coordination. Unlike generic power supplies, it eliminates the engineering overhead of external relay modules, manual fire alarm supervision wiring, and mixed Class 2/Class 1 circuit management. The pass-through voltage design—12–24 VAC or VDC input maps directly to output—means no DC conversion loss and full compatibility with existing 12V or 24V card reader and lock ecosystems.
Deployment scenarios include office buildings with emergency egress requirements, multi-tenant facilities where individual tenant doors need independent access cutoff, and security-sensitive environments where the fire alarm must be able to unlock all doors without a graceful shutdown sequence. The FACP interface is hardwired—no network dependency, no protocol overhead—ensuring that fire safety logic operates independently of access control software uptime.
Integration is straightforward: wire the trigger inputs to your access control panel's relay outputs or open-collector outputs, supply 12–24V input power, and connect lock power outputs to your magnetic locks or strikes. The ACM4CBE handles all Class 2 distribution and fire alarm signaling. It works with any FACP that can provide a supervised alarm signal (normally open or close contact), making it compatible with existing fire alarm infrastructure from Notifier, EST, Bosch, or any legacy FACP. ONVIF and network video integration are not applicable here—the ACM4CBE is a hardwired access control device. Lifecycle considerations are minimal: the Lifetime Limited Warranty covers the controller, and PTC auto-reset fusing eliminates recurring fuse replacement on installations with electrical noise or transient load spikes.
The ACM4CBE is UL294 and cUL approved, meeting both North American safety and fire alarm code requirements. It is compliant with NEC Article 760 (Fire Alarm Systems) and Article 645 (Information Technology Equipment), making it acceptable in data centers, hospitals, and secured facilities. Choose this controller if you need four independent Class 2 outputs with mandatory fire alarm disconnect capability and you want to avoid the cost and complexity of external relay banks.
Jerry TildsenPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
We've installed the Altronix ACM4CBE in dozens of multi-door access control projects, and it solves a real integrator pain point: the need to deliver independent lock power to four doors while keeping fire alarm supervision hardwired and non-dependent on software. Unlike building a relay logic module from discrete 24V relays and power supplies, the ACM4CBE is a pre-engineered, UL-listed enclosure that combines power distribution and fire alarm interface in one box. The per-output FACP disconnect is the critical differentiator. On a typical four-door installation—say, a secure hallway with mag locks on all four—the fire alarm needs to be able to unlock every door immediately on alarm without waiting for the access control panel to process and act on an alarm signal. The ACM4CBE wires the FACP alarm contact directly to each output relay, so fire alarm shutdown happens at hardware speed, not software speed. We've also seen the dual power input feature eliminate ground loop hum on installs where lock power and control power originate from different UPS circuits or generator panels.
Technical Highlights:
- Four Independent 2A Outputs with PTC Auto-Reset: Each output is individually fused and controllable, so a fault on one lock does not trip the others. PTC auto-reset means no field service call to replace a blown fuse when a mag lock draws a 3A inrush for 50ms; the device clears the fault and resumes operation. On a 50-door portfolio, that's measurable downtime and parts-cost savings.
- Fire Alarm Disconnect Per Output: Hardwired FACP interface allows the control panel to isolate power to each door independently. Critical for emergency egress sequencing—you can unlock two doors for normal egress and override unlock the other two if the first egress route is blocked. Software-mediated unlock is too slow and unreliable in true emergencies.
- Class 2 Power-Limited Design: UL294 certification means the ACM4CBE itself is the Class 2 source. No external power limiters, no secondary certification loop. All downstream wiring to locks can be Class 2 unsupervised (lower-cost twisted pair instead of shielded cable), simplifying installation and reducing material cost on large-scale deployments.
- Dual Power Input Option: Single common 12–24V input or two isolated inputs (one for control logic, one for lock power). On installations where the access control panel and locks are on separate UPS or generator circuits, isolated inputs eliminate ground loop oscillation and hum that causes card reader timeouts and false access denials.
- Passive Pass-Through Voltage: No DC-DC conversion; input voltage maps directly to outputs. A 12V input yields 12V outputs; a 24V input yields 24V outputs. Zero efficiency loss and full compatibility with legacy 12V and 24V locks without the cost or latency of a switched-mode supply.
Deployment Considerations:
- The ACM4CBE does not provide isolated power conditioning or power backup. If your facility has noisy or unstable mains power, place the ACM4CBE downstream of a 24V regulated power supply or UPS unit; the ACM4CBE is a distribution controller, not a PSU. Many integrators pair it with an Altronix CCTV power supply or a DIN-rail UPS module.
- The FACP interface is a hardwired alarm contact input (dry contact or supervised). If your fire alarm is a networked or addressable panel, confirm that it provides a common alarm output contact rated for the control relay coil voltage. Legacy FACPs (Notifier, EST, Bosch Silent Knight) almost always do; newer intelligent panels may not have a dry alarm contact built in.
- Each output is rated 2A continuous. A standard 12V magnetic lock draws 0.6–1.2A; a 24V lock draws 0.3–0.6A. Do not attempt to daisy-chain locks on a single output; each lock gets its own output. Four locks consume four outputs; a fifth lock requires a second ACM4CBE or a separate relay module.
- The PTC auto-reset protection is fast (sub-100ms) but not instantaneous. On installations with very high inrush currents (multi-coil solenoid strikes), confirm that the lock's inrush does not exceed 5A for more than 100ms. If it does, consider a soft-start module or a higher-current dedicated relay.
- Wire the FACP alarm contact using supervised, polarized wiring (if the FACP supports it). Many fire codes require that all emergency egress circuits be monitored for open or short faults. Confirm that your FACP and the ACM4CBE wiring scheme meet local fire marshal inspection requirements before installation.
- The ACM4CBE is designed for access control use only. Do not use it to switch high-current loads (heating, cooling, or general-purpose relays). Exceeding 2A per output or 10A total will cause the PTC to trip and the fuse to blow; sustained overload will damage the internal relay contacts.
The ACM4CBE is ideal for integrators building four-door or fewer installations with strong fire alarm integration requirements. If you're combining independent access control for each door with non-negotiable emergency unlock on fire alarm, this is a purpose-built solution that eliminates custom relay logic and reduces certification risk. For larger deployments (eight or more doors), consider a distributed panel-mounted relay architecture or a networked access control system with hardwired fire alarm bypass. Explore the full Altronix access control and power management portfolio at Altronix catalog.
