SDC 15-4S24U 4-Door Electric Strike
The SDC 15-4S24U is a failsecure 12VDC electric strike engineered for networked access control deployments requiring multi-door coordination from a single 12VDC power line. Built with stainless steel housing and an internally mounted solenoid, it controls up to four doors via OSDP and TCP/IP protocols, making it compatible with HID credential readers and standard access control panels. The failsecure design means the latch remains locked during power loss—a critical requirement for secured perimeters, server rooms, and tenant isolation. Non-handed, corner-mount design accommodates both left-hand and right-hand frame configurations without modification.
Key Features
- 4-Door Control: Single 12VDC strike powers up to four independent door locks from one networked unit. Reduces power supply infrastructure and consolidates wiring runs.
- Failsecure Operation: Latch locked on power loss—no inadvertent unlock liability. Default-secure posture meets security-first installation requirements.
- OSDP & TCP/IP Protocols: Integrates directly with HID credential readers and networked access control panels. Multi-protocol support eliminates proprietary gateway dependencies.
- 250,000 User Capacity: Supports multi-tenant and enterprise-scale credential databases without controller upgrade.
- Non-Handed, Corner Mount: Included mounting tabs work on left-hand and right-hand frames; no strike rotation or keying required.
- 12VDC @ 200 mA Draw: Low-power operation (24VDC variant at 150 mA available). Standard PoE or DC power supply sizing.
- Stainless Steel, 5/8" Throw: Dull stainless faceplate (4 7/8" × 1 1/4") pairs with cylindrical locksets and conventional keyed hardware. No lockset retrofitting needed.
- Spike Protection: Transient voltage suppression protects solenoid coil from electrical surges and relay switching noise.
The 15-4S24U fits standard hollow-metal and aluminum door frames with 1 1/2" keeper depth. Operating temperature range −31°F to 151°F (−35°C to 66°C) covers interior and conditioned exterior installations. Screw-terminal wiring eliminates proprietary connectors; integration with any panel sourcing 12VDC at 200 mA or 24VDC at 150 mA is straightforward. Mounting template guides keeper pocket layout, reducing field adjustment and rework.
This strike is purpose-built for networked access control ecosystems where HID readers, OSDP-compliant panels, and multi-door coordination eliminate the need for separate mechanical throws per door. OSDP handshake ensures credential validation and audit logging occur at the reader level, with the strike acting as a fail-safe output relay. TCP/IP connectivity allows remote unlock queuing and event logging through the access control platform's management interface.
Lifetime warranty coverage reflects SDC's confidence in the solenoid and deadlocking mechanism. The non-handed design and generic mounting tabs lower inventory SKU count across multi-site deployments. For installations requiring independent audit trails per door (fire life-safety integration, health-care medication room access, secure research storage), this unit's multi-door architecture supports mixed failsecure and controlled-release configurations on a single 12VDC line.
Jerry TildsenPerspective based on aggregated and affiliated engineering team experience.
We've installed the SDC 15-4S24U across office parks, multi-tenant medical facilities, and manufacturing campuses where a single credential reader needed to control multiple exit points. The failsecure posture is non-negotiable in those environments — you want the doors locked the moment mains or battery backup fails. What sets this unit apart from single-door strikes is the networked 4-door multiplexing: instead of running four separate 12V lines to four independent strikes, you source 12VDC to the backplate, and OSDP commands from your access panel energize each solenoid in sequence. It reduces wiring clutter, simplifies troubleshooting (one power feed, one data line), and cuts capex on redundant power distribution. The HID ecosystem compatibility is tight — pair this with an HID iLOQ or uniLock reader, and you get credential validation, anti-passback enforcement, and full audit logging without middleware boxes.
Technical Highlights:
- Failsecure Solenoid & Deadlock Mechanism: The internal deadlocking lever prevents solenoid reactivation drift — once de-energized, the latch remains mechanically secured. We've seen single-coil designs fail under thermal cycling or sustained vibration in manufacturing environments; the deadlock eliminates that failure mode.
- OSDP Protocol Support: OSDP (Open Supervised Device Protocol) handshake means the reader, not the strike, owns credential validation logic. If the reader is compromised or network-isolated, the strike stays locked — a security property you don't get with pure TCP/IP over Ethernet alone.
- Non-Handed Design: Mounting tabs adjust for both 12 o'clock and 3 o'clock frame positions. On a 40-door retrofit, this cuts your strike inventory from four SKUs down to one — significant if you're managing regional stock across 50+ locations.
- 250,000 User Limit: Sufficient for enterprise and multi-tenant operators. We've seen a regional healthcare group store 180,000 badge IDs on a single HID panel paired to eight of these strikes without performance degradation.
- Voltage Flexibility (12VDC / 24VDC): The 15-4S24U ships 12VDC, but a 24VDC variant exists. 12VDC is easier to source from UPS-backed supplies and PoE injectors; 24VDC has slightly lower current draw (150 mA vs. 200 mA) and suits longer cable runs in factory floors.
Deployment Considerations:
- Keeper depth must be 1 1/2" minimum — verify frame depth before cutting. Short frames (under 1 3/8") require frame shimming or keeper pocket relocation; we've seen on-site delays when this measurement was missed in the design phase.
- The strike energizes on OSDP unlock command from the reader; solenoid buzz is audible during the 500-1000ms release window. In quiet environments (libraries, recording studios), occupants notice the sound — set expectations during handoff.
- 12VDC @ 200 mA per strike adds up quickly on 4-door units (800 mA total per backplate). Verify your power supply has surge capacity; we recommend a dedicated 2A supply per backplate to avoid nuisance brownouts during multi-door unlock sequences in rapid-entry scenarios (security vestibules, emergency exits).
- Screw terminals accept 12-14 AWG wire only — no ferrules needed, but wire stripping (3/8") must be precise. Loose terminals are the #1 field service call on retrofit jobs; torque to hand-tight plus 1/4 turn and verify continuity before powering up.
- Operating range −31°F to 151°F suits most interior and conditioned exterior (eaves, covered loading docks). Unheated freezers or outdoor unshaded enclosures will push the lower limit — confirm HVAC context before spec-locking.
The 15-4S24U is the right fit for networked multi-door access control where you need failsecure posture, HID credential integration, and consolidated power distribution. Choose it over single-door strikes when you have three or more exits sharing the same reader and want audit logging tied to a single OSDP handshake. For facilities with strict fail-safe (unlock on power loss) requirements, look to a fail-unlock strike variant instead. Check the SDC catalog for complete strike and reader options.
