Camden CM-3250 Key Switch 2 SPDT Momentary
The Camden CM-3250 is a dual single-pole double-throw (SPDT) momentary key switch designed for 30VDC access control systems requiring independent circuit activation from a single keyway. The flush-mount stainless steel assembly integrates into multi-door environments, emergency egress schemes, and applications where two separate control paths must operate from a single mechanical key. Each SPDT circuit closes momentarily upon key turn and returns to open position upon key release, eliminating the need for latching relays or logic-level control.
Key Features
- Dual SPDT Momentary Circuits: Two independent single-pole double-throw switches on one assembly. Enables simultaneous activation of two separate door strikes, electronic locks, or auxiliary devices from a single keyway without controller logic overhead.
- 30VDC Operating Voltage: Direct integration with standard 24/30VDC access control power supplies and controller outputs. Supports most lock-and-strike installations without supplementary power conditioning.
- Stainless Steel Double-Gang Faceplate: IP65-grade corrosion resistance and flush-mount design. Rated for indoor and outdoor environments including loading docks, emergency exits, and weathered entrances.
- Mortise Cylinder Mounting (1", 1 1/8", 1 1/4"): Accepts one or two standard mortise cylinders with integral cylinder locators preventing rotation during key insertion. Eliminates set screw hardware and simplifies maintenance.
- Tamper/Vandal-Resistant Assembly: UL/CSA approved. Tamperproof screws with driver included; color-coded 18 AWG soldered leads with heat-shrink protection withstand mechanical stress and environmental exposure.
- Up to Four Switch Positions: Double-gang housing accommodates additional switches for expanded circuit control on a single faceplate if required by project scope.
Access control integrators commonly spec the CM-3250 in two-door entrance schemes (e.g., outer vestibule + inner door), emergency egress scenarios where dual independent signals reduce single-point-of-failure risk, and applications requiring manual override or secondary release without introducing network dependencies. The mechanical key actuation provides analog-resilient control in environments where card readers or biometric sensors may be unavailable or unsuitable.
The assembly ships with brass cylinder lock rings, four socket/slotted mounting screws, and four tamperproof screws with driver. Mortise cylinders are sold separately; source from Camden or any compatible lock manufacturer. Wiring termination uses soldered leads, requiring field crimping or screw-terminal connection to the access control panel. The faceplate supports both left and right key operation depending on installation orientation — field-adjustable at mount time.
In commercial access control deployments, the CM-3250 eliminates the cost and complexity of installing separate key switches or expanding control panel I/O. Integration is straightforward: each SPDT pair connects as normally-open momentary inputs into the controller's door-release or auxiliary circuit card. No VMS integration, no IP overhead — purely hardwired mechanical and electrical reliability. UL/CSA certification ensures code compliance in life-safety and emergency egress applications.
The product suits integrators building access control retrofits on older buildings where card-reader installation may be costly or where dual-path mechanical override is mandated by local fire code. Pair with standard 30VDC strikes and a commercial-grade access panel for a turnkey entry solution that does not depend on network connectivity or software licensing.
Eden PhillipsPerspective based on aggregated and affiliated engineering team experience.
We've installed the Camden CM-3250 on dozens of two-door vestibule systems and emergency egress retrofits where the client needed independent key-operated circuits without adding hardware or complexity. The real value is mechanical simplicity: no relay cards, no intermediate switching logic, no single-point network dependency. A key turn directly drives two separate 30VDC circuits — one fires the outer door strike, the other the inner lock, or vice versa, depending on wiring. In environments where power-loss scenarios or network unavailability are operational concerns, that hardwired reliability is gold. The stainless steel construction handles outdoor mounted installations — we've spec'd this on loading docks, secured parking gates, and rooftop mechanical rooms without corrosion issues over five-year lifecycles. One caveat: the SPDT momentary action requires continuous key pressure; once released, both circuits drop. If your logic requires latched behavior, you'll need to wire a relay into the loop. For applications where dual momentary signals suffice (e.g., two strikes that should only fire while the key is turned), this is the most cost-effective solution in the Camden lineup.
Technical Highlights:
- 30VDC Direct Integration: No power conditioning or intermediate drivers needed. Connects directly to standard access control power supplies and controller outputs. Simplifies BOM and reduces field wiring labor on retrofit projects.
- Dual Independent SPDT Pairs: Two completely isolated circuits allow simultaneous activation of separate doors, locks, or auxiliary devices from one keyway. Eliminates the cost of installing parallel key switches or card readers.
- Mortise Cylinder Locators (No Set Screws): Integral locating pins prevent cylinder rotation during key insertion. Reduces assembly time and eliminates frustration with set screw loosening over time in high-traffic doors.
- UL/CSA Code Compliance: Approved for life-safety and emergency egress applications. Meets local fire codes requiring mechanical override or dual-path activation in controlled-access buildings.
- Stainless Steel + Heat-Shrink Wiring: Resists corrosion in outdoor, humid, and chemical environments. Soldered leads with protective sleeves survive vibration and mechanical stress without intermittent contact failures.
Deployment Considerations:
- Mortise cylinders are not included — budget and source separately. Standard 1", 1 1/8", or 1 1/4" mortise keying is widely available from Camden and other manufacturers, but lead time and SKU variance can extend project schedules if not ordered early.
- Momentary action requires continuous key pressure. If your system logic requires latched or timed lock-release (e.g., strike must remain energized for N seconds after key release), you must add a relay card or solenoid timer in the circuit. Plan wiring accordingly.
- Double-gang faceplate is bulkier than single-gang alternatives. On narrow door frames or stile-mounted applications, confirm mounting clearance before specifying. The assembly mounts flush, but the footprint occupies both positions on a standard electrical box.
- Color-coded 18 AWG leads are terminated with solder. Field connection to the access panel typically requires butt connectors, screw terminals, or solder-pot integration — no plug-and-play connectors. Plan termination hardware and crew skill level during bid phase.
- Each mortise cylinder should be keyed identically to ensure both SPDT pairs respond to the same key. Rekeying or master-keying the CM-3250 assembly requires re-pinning the mortise cylinders — a locksmith task that may not be in-scope for the integrator.
The CM-3250 is the right choice for access control projects requiring mechanical dual-circuit activation without adding card readers, biometric hardware, or network connectivity. It's equally valuable as a life-safety override or emergency egress device. For straightforward two-door vestibules, single-key redundant strike control, or hardwired panic-release scenarios, this product delivers cost efficiency and proven reliability. Explore the full Camden catalog for complementary strikes, exit devices, and access control hardware.
