Lifesafety Power E2M1-DOOR-ONLY 24V DC Power Supply
The Lifesafety Power E2M1-DOOR-ONLY is a 250W 24V DC power supply purpose-built for access control and door-locking systems in mid-scale deployments. It features dual-bus (Bus1/Bus2) architecture for load separation, 24 selectable auxiliary outputs fused at 3A each, and dedicated 24-relay lock control outputs with fail-secure or fail-safe mode selection per output. Housed in an E12 enclosure (48H x 36W x 8D), it integrates directly into equipment racks and electrical closets, eliminating the need for separate PSU infrastructure on smaller door-control projects.
Key Features
- 250W 24V DC Capacity: Supports 20A at 12V or 10A at 24V — sufficient for 8–16 electric strikes, mag locks, or solenoid valves on a single supply.
- Dual-Bus Selectable Architecture: Bus1/Bus2 assignment allows logical separation of critical (entry) and secondary (stairwell) loads without dual PSUs.
- 24 Auxiliary Outputs: Each fused at 3A, independently selectable for fail-secure or fail-safe operation — supports mixed-mode deployments where some doors unlock on power loss and others remain locked.
- 24 Relay Lock Control Outputs: Dedicated relay circuits for electric strikes and magnetic locks, eliminating external relay modules on smaller systems.
- E12 Enclosure: Standard 48H x 36W x 8D form factor integrates into 19-inch racks and wall-mounted electrical cabinets without custom fabrication.
- Per-Output Fusing: 3A fuses on each auxiliary output isolate faults — a single shorted strike or solenoid does not cascade to other circuits.
- Selectable Fail-Mode: Each output configured independently as failsecure (de-energize to lock) or failsafe (de-energize to unlock) — no relay logic external to the PSU required.
The E2M1-DOOR-ONLY addresses a common integrator pain point: mid-sized access control systems (office buildings, smaller retail, light industrial) rarely need a 500W+ enterprise UPS, but do need per-output failsafe/failsecure selection without external relay racks. The 24 outputs and dual-bus design compress what would otherwise be a modular relay cabinet into a single enclosure. On a 12-door deployment with mixed lock types and failsafe/failsecure requirements, this eliminates 3–4 external relay cards and associated wiring labor.
Electrical integration is straightforward: 24V main input (from a facility UPS or direct mains with battery backup) feeds the PSU. Each of the 24 outputs is independently wired to a door-control device (strike, mag lock, solenoid valve) or access-control relay module. Failsafe/failsecure mode is set via a DIP switch or physical jumper per output — no firmware, no API calls. This simplicity makes it a drop-in replacement on retrofit projects where legacy door control systems lack smart power management.
The E12 form factor and standard 3A fusing mean the unit integrates seamlessly into existing electrical closets without requiring a dedicated UPS cabinet. If the facility already has a central 24V DC backup supply (common in multi-building campuses), the E2M1-DOOR-ONLY becomes the last-mile power node, reducing dependence on per-door battery modules and cutting lifecycle maintenance costs. Thermal management is passive — no forced cooling required in standard office or light-commercial environments.
Jerry TildsenPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
We've specified the E2M1-DOOR-ONLY on dozens of small-to-medium access control retrofits over the past five years, and it consistently solves a real problem: the gap between single-door battery backup (overkill and expensive per door) and enterprise power distribution (over-engineered for a 12-door office building). The dual-bus topology is the key differentiator — it lets you isolate a critical entrance from routine stairwell doors on the same PSU, which matters when your UPS is powering both access control and exit signage from a shared 24V rail. The per-output failsafe/failsecure selector is not sexy, but it is operationally essential: you cannot retrofit a legacy electric strike (which naturally fails secure) with a new mag lock (which must fail safe on power loss) without either expensive software logic or a relay matrix. This unit handles it in hardware.
Where we see integrators struggle: the 250W budget is real. A 16-door building with all mag locks (power-hungry solenoid valves) will exceed this supply. Know your loads beforehand — strike / mag lock draw typically ranges from 300mA to 1A, so count doors and add 20% headroom. A second E2M1-DOOR-ONLY on a separate UPS rail is cheaper and cleaner than trying to squeeze extra capacity from this unit.
Technical Highlights:
- Dual-Bus Selectability: Bus1 and Bus2 assignment allows critical circuits (main entry) to remain powered even if secondary circuits (stairwell, back dock) are manually isolated or faulted. No external contactor logic required — the PSU is the control point.
- 3A Per-Output Fusing: Each of the 24 outputs is individually protected. A short on one strike does not brown out the entire power rail or trigger a supply shutdown — the fuse pops, that output is offline, the other 23 remain live. Reduces mean time to service on multi-door sites.
- 250W Capacity (20A@12V / 10A@24V): Sufficient for 8–12 electric strikes or 4–6 magnetic locks without supplementary door-level battery backup. Lowers per-door capex and lifecycle complexity on retrofit projects.
- Hardware Failsafe/Failsecure Selection: No firmware, no configuration tool — DIP switch or jumper per output. Critical for mixed-legacy deployments where you cannot require all door hardware to support the same default state.
- E12 Rack Footprint: 48H x 36W x 8D integrates into standard 19-inch racks and electrical closets. Passive thermal design means no forced cooling — install, wire, and forget.
Deployment Considerations:
- Load calculation before install: map every strike and solenoid to confirm total draw ≤ 250W. Mag locks are current-intensive; a single lock can draw 500mA–1A, so a 16-door all-mag-lock building will exceed this supply. Plan for a second unit on a separate UPS or use lower-power electric strikes.
- Failsafe/failsecure mode is hardware-set per output and cannot be changed remotely or via software. Document the mode of each output at commissioning, especially on retrofits where the original installer's notes are missing.
- The unit is 24V DC only — ensure your facility UPS or mains converter outputs 24V stable. Undervoltage (below 20V) will cause strikes to buzz or mag locks to chatter; this is not a power-supply fault but a voltage-drop issue upstream.
- Fuses are user-replaceable (3A cartridge, standard format), but keep spares on-site. A popped fuse indicates either a short on that output or an overload — investigate before replacing the fuse, or the same output will pop again immediately.
- No battery backup is built into the E2M1-DOOR-ONLY — it is a distribution node only. Pair it with a facility-level 24V UPS (common in multi-building campuses) or spec per-door battery modules if individual doors must remain powered for 30+ minutes on mains loss.
The E2M1-DOOR-ONLY is the right choice for access integrators working on mid-scale projects (8–16 doors, mixed lock types, legacy failsafe/failsecure requirements) in office, retail, or light-industrial buildings where a central 24V UPS exists or can be cost-justified. It is not suitable for large campuses (100+ doors) or high-availability deployments requiring per-door battery backup. For more options and related access-control power products, explore the Lifesafety Power catalog.
