Lifesafety Power C8-BOXED 8-Output Relay Lock Control Module
The Lifesafety Power C8-BOXED is a relay-based access control output module designed to switch power to electronic locks, magnetic locks, and door strikes on distributed door control systems. It provides 8 independent relay outputs, each capable of handling the inrush and steady-state current demands of fail-secure and fail-safe lock hardware across multiple doors. The C8-BOXED eliminates the integration overhead of provisioning individual relay boards at each lock location — a single module mounted in a central equipment cabinet can manage power switching for an entire building entry system or multi-door secure corridor.
Key Features
- 8 Independent Relay Outputs: Each output is electrically isolated, allowing independent switching of locks at different doors or on different voltage supplies without cross-talk or control bleed-through.
- Dry Relay Contact Switching: Accepts dry relay contact signals (5VDC to 24VDC logic) from any access control panel, door controller, or card reader; no active driver circuitry required on the panel side.
- Fused & Class 2 Variants: Supplied in two electrical configurations — fused HVAC-grade for standard 12/24VDC solenoid locks, or Class 2 low-voltage signaling-grade for signal-only applications.
- Solenoid Lock Rated: Relay contacts rated for 3–5A @ 24VDC, sufficient for typical magnetic lock inrush (0.5–1.5A) and fail-safe strike solenoids without contact chatter or burnout.
- Compact Enclosure Form Factor: DIN-rail mountable or wall-mounted cabinet module, sized to fit standard 2U rack or above-door equipment shelf. Minimal footprint in crowded electrical rooms.
- No External Power Supply Dependency: Relay module draws logic power directly from the access control panel or a separate 24VDC auxiliary supply; no additional UPS or battery backups required at the module itself if the panel is backed up.
- Visual Status Indicators: LED indicators on each relay output channel enable rapid commissioning verification and field troubleshooting without multimeter access.
- Field-Replaceable Relay Cartridges: Relay modules can be swapped without full enclosure replacement if a single output channel fails — lowers mean time to repair on multi-door systems.
The C8-BOXED is the standard workhorse for integrators managing access control installations in mid-scale deployments — office campuses, multi-tenant buildings, secure storage facilities, and industrial access corridors. Where a single access control panel cannot provide sufficient switching current or isolation, the C8-BOXED offloads the relay load and allows clean separation of panel logic circuits from high-inrush solenoid circuits.
Installation context matters for this module. Proper voltage reference uniformity across all 8 outputs prevents nuisance relay chatter; mixed 12VDC and 24VDC lock loads on the same module lead to inconsistent switching and false alarms. Inrush current — the instantaneous spike when a solenoid coil energizes — must be factored into relay selection. A standard magnetic lock draws 1–1.5A steady-state at 24VDC, but inrush can peak at 2–3× that value for 10–50ms. The C8-BOXED relay contacts are rated for this transient — but only if the wiring gauge and panel output circuit protection are correct. Undersized wiring or a 5A panel fuse will drop voltage during inrush, leaving the lock energized but underpowered, creating intermittent access failures. Verify lock current specs before commissioning.
Integration with access control platforms is straightforward because the C8-BOXED is electrically transparent — it has no firmware, no IP address, and no protocol stack. Any panel or controller that outputs dry relay contacts can drive it. Genetec Security Center, Milestone XProtect, and Salto ACS all integrate with the C8-BOXED indirectly through the underlying door controller (Salto NG or Standalone, Honeywell ProWatch, etc.). The module itself imposes no VMS or management software dependency. Wiring separation is a code compliance issue: fused HVAC-grade outputs must be segregated from Class 2 logic wiring by at least 4 inches or in separate conduit runs per NEC Article 725. Comingled wiring can induce noise on low-voltage signaling circuits and cause unpredictable reader responses. Route all 24VDC solenoid loops in rigid conduit away from data and RS-485 bus runs.
Total cost of ownership for a multi-door access system improves when a C8-BOXED is specified early: one central relay module, one power supply, and one set of conduit runs replace eight separate single-relay boxes, eight auxiliary power feeds, and eight equipment mounting locations. Maintenance is simpler — a single point of relay health monitoring and a single enclosure to inspect for oxidation or loose terminals. End-users benefit from deterministic lock response: all 8 outputs share the same power supply and logic timing, so multi-door unlock sequences (e.g., emergency egress on a secure corridor) fire within milliseconds of each other, not staggered or delayed by distributed relay boxes.
The C8-BOXED is designed to operate within a standard 24VDC access control power ecosystem. It carries no specific compliance certifications (UL, FCC) beyond the underlying enclosure NEMA rating; certification derives from the total system (panel + module + wiring) rather than the relay module alone. Specify this module when you need reliable, field-proven relay switching for 8 or fewer doors in a centralized equipment location. It is not suitable for wireless or networked deployments — all control signals must be hard-wired from the panel.
Jerry TildsenPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
We've installed dozens of C8-BOXED modules across everything from small office renovations to large multi-building campuses, and it remains a reliable anchor point for access control relay switching. The reason is simple: it has no intelligence, no firmware updates, and no network dependency — a relay either works or it doesn't, and when it fails, you swap the cartridge and move on. Where we see the C8-BOXED shine is in retrofit projects where an existing door controller lacks sufficient relay output capacity, or in new builds where centralizing relay logic in a single equipment room simplifies both wiring and troubleshooting. The alternative — individual relay boards scattered above each door — creates maintenance nightmares: you have to climb a ladder to every lock location just to verify relay status, and if one relay fails, you have to replace a full board instead of a single cartridge.
The most common misstep we see is voltage mismatch. A customer installs a mix of 12VDC and 24VDC locks on the same C8-BOXED, expecting the module to act as a level-shifter. It doesn't. Each relay output is a simple electromechanical switch — it has no voltage regulation or conversion. If you wire a 12VDC lock across a 24VDC output, the lock gets 24V, draws double current, and either overheats immediately or fails within weeks. Always verify all lock solenoids operate at the same voltage before assigning them to the same module. If you need mixed-voltage switching, order two C8-BOXEDs — one for 12V locks, one for 24V.
The second issue is inrush current planning. A mag lock draws 1.2A at 24VDC steady-state, but inrush can hit 2.5–3A for the first 20ms. If your control panel's output circuit is protected by a 3A fuse, and you energize 3 locks simultaneously, the inrush totals 7.5–9A — the fuse blows immediately. You never see a failure in the C8-BOXED relay itself; the panel fuse just opens the entire output bus. The solution is to either stagger unlock sequences in software (unlock door 1, wait 50ms, then unlock doors 2 and 3), or increase the panel's output circuit protection to 5–10A and verify wire gauge matches. Always pull the lock manufacturer's datasheet and add up the inrush current across all locks that will energize in parallel.
Technical Highlights:
- 8 Independent Relay Outputs, Electrically Isolated: Each channel is completely decoupled from the others, preventing a short or overload on one output from affecting the remaining 7 channels. Operational consequence: if a single lock solenoid shorts and the relay welds closed, the other 7 doors remain controllable while you diagnose and replace that lock's relay cartridge.
- Solenoid-Rated Relay Contacts (3–5A @ 24VDC): Relay contacts are selected and tested for the inrush and holding current of typical access control solenoids. Standard general-purpose relays (rated only for resistive loads) will chatter or burn out under solenoid inrush. The C8-BOXED uses contacts hardened for inductive switching, extending relay life to 2–5 million cycles (5–10 years of daily use on a typical door).
- Dual Electrical Variants (Fused & Class 2): The fused version carries 24VDC power directly from the lock supply to the relay contacts, suitable for high-current solenoid switching. The Class 2 variant outputs low-voltage logic signals only, used when the relay module sits between a control panel and a separate lock controller that handles the actual solenoid switching. Choosing the right variant avoids costly rewiring or safety compliance violations.
- Dry Relay Contact Inputs (5–24VDC Logic): The module accepts control signals from any panel or reader that outputs dry relay contacts or digital logic. No proprietary protocol, no API, no firmware — any 24VDC access control panel (Honeywell, Salto, Lenel, etc.) can drive it. This simplicity is a feature: in 10 years, when the panel is end-of-life, you can still use the C8-BOXED with a replacement panel.
- Field-Replaceable Relay Cartridges: Individual relay modules can be removed and swapped without desoldering or opening the main enclosure. On a system with 8 locks, replacing a failed relay takes 2 minutes. Without field-replaceable cartridges, you'd replace the entire module or send it for depot repair.
- Visual LED Status Indicators per Channel: Each output has an LED that lights when that relay energizes. During commissioning, you can verify that the access control panel's unlock command actually reaches the C8-BOXED and closes the relay, narrowing troubleshooting to the panel logic or wiring before blaming the locks themselves.
Deployment Considerations:
- Voltage Uniformity Required: All 8 relay outputs must be wired to locks operating at the same voltage (either all 12VDC or all 24VDC). A single 12VDC lock mixed with seven 24VDC locks will be overpowered and fail. If your site has mixed-voltage locks, order two modules — one for each voltage class — or specify a new lock standard during procurement.
- Inrush Current Planning: Calculate total inrush current across all locks that unlock in parallel. If your access control panel's output circuit is protected by a 3A fuse and you unlock 3 mag locks simultaneously (3A × 2.5× inrush = 7.5A), the fuse blows and all locks lose power. Verify panel circuit protection rating and wire gauge can handle 5–10A transient load, or program unlock sequences to stagger in software.
- Wiring Segregation (Code Compliance): On fused variants, separate 24VDC solenoid power runs from Class 2 logic signals by at least 4 inches or in separate conduit per NEC Article 725. Comingled wiring induces 60Hz hum and noise on low-voltage card reader and RS-485 bus signals, causing random reader timeouts and false rejects. Use rigid conduit for long runs.
- Enclosure Mounting Location: Mount the C8-BOXED in a climate-controlled electrical room or above-door cabinet, not in a basement boiler room or outdoor enclosure. Heat and humidity shorten relay life and increase oxidation on contact surfaces. If outdoor mounting is unavoidable, specify a sealed IP65 enclosure and include a desiccant drying cartridge.
- Integration with Multi-Door Unlock Sequences: When the access control panel energizes multiple C8-BOXED outputs for emergency egress or corridor unlock, all 8 relays respond within 10–20ms of each other because they share the same power supply and logic timing. This deterministic behavior is valuable for compliance: emergency egress doors open in lockstep, not staggered, reducing evacuation time variability.
The C8-BOXED is the right module for integrators and end-users managing centralized access control relay switching across 4–8 doors in a single building or secure area. It is the proven alternative to eight single-relay boxes, and it scales cleanly: if you need 16 outputs, you run two C8-BOXEDs side-by-side on the same power supply. For wireless, networked, or highly distributed access systems, this module is the wrong choice — specify a networked relay controller instead. For straightforward wired access control, the C8-BOXED remains the standard. Explore the full range of access control solutions and switching modules in the Lifesafety Power catalog.
