Lifesafety Power FPO250-3C83D8PE12M 250W Power Supply
The Lifesafety Power FPO250-3C83D8PE12M is a 250W power distribution platform designed for access control, electric lock, and alarm system integration in mid-to-large installations. It delivers 20A at 12V or 10A at 24V DC with redundant bus architecture (Bus1/Bus2) to separate load paths, reducing single-point-of-failure risk on critical life-safety circuits. The 24 relay-output card slots and per-output failsafe/failsecure configurability make it a standard backbone for multi-door access control deployments where power distribution, relay switching, and auxiliary 24V circuits must coexist in one enclosure.
Key Features
- Primary DC Output: 20A @ 12V or 10A @ 24V selectable. Supports simultaneous lock control and auxiliary device powering with adequate reserve margin for solenoid inrush.
- 24 Relay Lock Control Outputs: Each output fused at 3A, independently selectable for FAI (Fail As Is), failsafe (de-energized unlock), or failsecure (energized lock) mode. Enables granular door-by-door access policy without secondary relay modules.
- Dual Bus Architecture: Bus1 and Bus2 outputs allow split load distribution — common pattern: Bus1 drives north-side locks, Bus2 drives south-side to eliminate daisy-chain voltage drop over long conduit runs.
- Class 2 Auxiliary Outputs: 24V DC outputs power-limited at 2.5A per circuit per code, ideal for card readers, motion sensors, or low-power signaling devices. Bus-selectable for routing flexibility.
- Mercury Backplate Mounting: E12 enclosure (48H × 36W × 8D inches) accepts standard Mercury-compatible relay modules and control cards; field-proven retrofit compatibility with legacy access control systems.
- Per-Output Fusing & Isolation: 3A fuses on each relay output prevent a single shorted lock from cascading outage across remaining 23 outputs. Integrated disconnect for maintenance without full circuit kill.
Mid-to-large access control systems often face the topology challenge of powering 16+ electric locks, badge readers, and alarm signaling from a single source without incurring voltage sag or contention delays on shared bus logic. The FPO250 solves this by isolating each lock circuit with its own fused relay output and dedicating a separate 24V auxiliary bus for low-power sensors. On a 24-door office building, you size one FPO250 per floor or per wing, avoiding the cost and complexity of distributed power supplies and reducing conduit congestion.
The dual-bus relay card design also supports graceful degradation: if Bus1 experiences an overload or connector fault, Bus2 continues supplying failsecure power to the opposite side of the building, keeping at least half the perimeter locked while maintenance is dispatched. This architecture is especially valuable in healthcare, government, and corporate campuses where a full power-distribution failure triggers lockdown protocols and audit liability.
Integration is straightforward: the FPO250 mounts in a standard 19-inch or wall-mount cabinet and accepts wired relay inputs from access control panels (Honeywell, Genetec, Axis Companion, etc.) via screw terminals. No ONVIF or network protocol — it's a hardwired power distribution platform. Field programming of failsafe/failsecure mode is done via jumper headers or DIP switches on each output card, allowing different lock types (magnetic locks, electronic strikes, mag-locks with solenoid release) to coexist on the same supply without firmware updates.
The FPO250-3C83D8PE12M is a foundational component in access control rollouts where power reliability and circuit isolation are non-negotiable. Pairs well with backup battery systems (UPS or Lead-acid bank) for failsecure hold-in-place during mains loss. Ensure your conduit run from panel to the furthest lock does not exceed 500 feet at 12V; if it does, step up to 24V output or add secondary power supplies per National Electrical Code guidelines.
Marty AllisonPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The Lifesafety Power FPO250 is one of the few mid-range power supplies that doesn't compromise on circuit isolation for the sake of compact form factor. We've deployed hundreds of these units across K-12 schools, office parks, and municipal buildings, and the appeal is always the same: each lock gets its own fused output, so a single electromagnetic interference (EMI) event or a maintenance technician accidentally shorting a solenoid doesn't take down the whole building. On a 24-door office expansion, the alternative is either daisy-chaining individual power supplies (cable management nightmare, higher aggregate failure rate) or specifying a larger 500W unit with overkill capacity and wasted power consumption. The FPO250 hits the sweet spot. The dual-bus design is less about redundancy in the traditional sense and more about spatial load distribution — Bus1 and Bus2 allow you to drive locks on opposite ends of a long hallway without voltage sag on either run. We've seen voltage drop cut by 2–3V on the far end of a 400-foot run when loads are split versus daisy-chained on a single output.
Technical Highlights:
- Per-Output 3A Fusing & FAI/Failsafe/Failsecure Selectability: Each of the 24 relay outputs can be jumpered for independent lock behavior — magnetic locks set to failsecure (energized = locked), strikes set to failsafe (de-energized = unlocked). Single shorted output doesn't propagate; protects against a single bad solenoid or moisture ingress taking the whole power distribution down.
- 20A @ 12V or 10A @ 24V Selectable Output: 12V is a legacy standard for old magnetic locks and legacy card readers; 24V is lower current draw and supports longer conduit runs (voltage sag reduction). Configuration is a jumper change — no firmware or field recalibration. Choose based on your installed lock base and the length of your runs.
- Class 2 Power-Limited Auxiliary Outputs: Rated 2.5A per output and code-compliant for low-voltage signaling devices (motion sensors, door position switches, intercom buzzers). Eliminates the need for a separate Class 2 power supply on the same cabinet and reduces total enclosure footprint and conduit entry points.
- Mercury Backplate & E12 Form Factor: The Mercury standard is ubiquitous in legacy and mid-tier access control installations. The FPO250 fits into existing cabinets and racks without adapters; if you're doing a mixed-brand retrofit (old Honeywell panel + new Genetec, for example), form-factor compatibility is a real time-saver on site visits.
- Integrated Disconnect & Field Serviceable: Each relay module can be pulled live without disrupting the rest of the system — useful when swapping a failed output card or diagnosing a stuck relay during business hours. Not every power supply offers this modularity.
Deployment Considerations:
- Voltage drop is real on long runs (200+ feet): test your 12V configuration at full load (all locks energized) at the furthest solenoid before commissioning. If voltage sags below 10V, switch to 24V output or add a secondary feeder from the supply to that zone. We've had field callbacks where a 300-foot run on 12V sagged to 8V under worst-case (all perimeter locks actuating simultaneously), preventing reliable solenoid release.
- The dual-bus design does NOT provide true redundancy in the sense of a backup power path — it's load distribution. If the main 24V rail fails, both buses go down. For true failsafe hold-in-place during mains loss, add a 12V SLA (sealed lead-acid) backup battery bank rated for your worst-case lock dwell time (usually 10–30 seconds).
- Relay output card jumpers are field-accessible but require a technician with a multimeter to verify polarity and FAI/failsafe logic during commissioning. Document your jumper configuration (photo or spreadsheet: door 1 = failsecure, door 2 = failsafe, etc.) — this knowledge often doesn't survive a technician turnover.
- The 3A fuse on each relay output is protective but also a constraint: electromagnetic strikes pulling 3.5A will nuisance-trip. Size your locks conservatively (2A nominal, 2.5A inrush max) and test inrush on the first unit before rolling out across 20 doors.
- Conduit termination: use compression fittings for the input 12/24V and ground; standard set-screw terminal boxes are acceptable for relay outputs but prone to vibration creep. Spend the extra time on strain relief and you'll avoid call-backs in year 2.
The FPO250-3C83D8PE12M is the right fit for mid-size access control systems (16–32 doors) where circuit isolation, failsafe granularity, and field modularity matter more than a sleek, minimalist footprint. Integrators and end-user teams managing campus-wide access expansion should start here before over-specifying a larger unit. See the Lifesafety Power catalog for complementary battery backup and load-shedding modules.
