SDC 413MNU Electronic Timer Exit Switch
The SDC 413MNU is a fixed 30-second electronic timer exit switch engineered for emergency egress and access control door release scenarios in commercial and industrial environments. The 2-inch square illuminated pushbutton (green lens) mounted on a narrow stainless steel faceplate meets NFPA signage requirements and delivers high-visibility activation. Operating on 12/24 VDC ±10%, the 413MNU provides a DPDT contact rated 3 amps at 30 VDC resistive — sufficient for controlling electromagnetic strikes, door operators, and relay circuits across multi-door access control installations. The high-impact-resistant button and 20-gauge stainless steel construction withstand sustained public use in high-traffic egress points without degradation.
Key Features
- Fixed 30-Second Timer Output: DPDT relay contact holds door release for 30 seconds on each activation. Ideal for standard electromagnetic strike control; no external timing module required.
- 3-Amp Relay Rating at 30VDC: Drives electromagnetic strikes, magnetic locks, and solenoid operators in single-door or multi-door control loops. Parallel contact allows simultaneous release + alarm suppression.
- Dual Voltage Supply (12/24 VDC ±10%): Operates from either 12V or 24V regulated supply with ±10% tolerance. Compatible with standard access control power distributions.
- NFPA-Compliant Button Design: Green 2-inch illuminated lens mounted on narrow 1¾" × 4½" stainless steel faceplate. Meets egress signage and ADA height placement requirements (36–48 inches AFF).
- Stainless Steel Construction: 20-gauge frame resists corrosion and impact damage in high-traffic public areas. Button mechanism rated for continuous institutional use.
- 6-Inch Lead Wires (20 AWG): Factory-terminated for direct connection to junction boxes or terminal blocks. Simplifies rough-in and retrofit installations.
- Lifetime Warranty: Manufacturer-backed warranty covers defects in materials and workmanship across the product lifecycle.
The 413MNU integrates into standard 24VDC access control systems as a secondary release trigger or primary egress-point activation. The DPDT contact topology allows simultaneous control of multiple load circuits — for example, strike release + door alarm reset — without additional external relays. Wire leads are pre-terminated at 6 inches (20 AWG) to reduce field termination labor; for longer runs, use intermediate junction boxes or relay modules to extend control signal distribution.
Installation is straightforward on interior wall frames fitted with standard exit-switch rough-in cutouts. The narrow faceplate (1¾" × 4½") fits legacy and new construction openings. Verify local ADA and NFPA 101 Life Safety Code requirements for button height and placement — typically 36–48 inches above finished floor — and confirm that the door release load does not exceed 3 amps at 30VDC. Oversized electromagnetic strikes or magnetic lock pulls that exceed 3 amps require an external relay upstream of the 413MNU contact.
The fixed 30-second timer output is optimized for standard electromagnetic strike hold scenarios common in office buildings, hospitals, and institutional facilities. If variable or extended timing (beyond 30 seconds) is required, deploy a separate adjustable timer module or time-delay relay in series with the 413MNU input signal. This modular approach preserves the simplicity and reliability of the exit switch while allowing site-specific timing customization.
The 413MNU is UL-listed for use in Life Safety and access control applications. Its robust construction, field-proven DPDT relay, and ADA-compliant button design make it a standard choice for egress control retrofit and new system deployments across hospitality, healthcare, corporate, and retail environments. The stainless steel faceplate and green illuminated lens signal clear egress intent to occupants and emergency responders alike.
Jerry TildsenPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
We've specified the 413MNU across hundreds of retrofit and new-construction access control projects, and it remains one of the most reliable hardwired exit-release switches in the market. The core value proposition is simplicity: a fixed 30-second timer, a proven DPDT relay, and no external logic required. On a 50-door multi-tenant office building, that translates to fewer potential failure points and lower service overhead compared to networked electronic locks or software-timed releases. The green illuminated button is immediately recognized by occupants and first responders as an egress point — no training, no confusion. Where we see the 413MNU shine is in high-traffic areas where button activation is frequent and unpredictable (hospital nurses' stations, retail emergency exits, school hallways). The button mechanism is mechanical and rugged; we've pulled units after 10+ years in service with zero relay failure. The one trade-off: the 30-second timer is fixed. If you need variable timing, you're adding an external timer module or relay, which complicates the bill-of-materials and adds a maintenance surface. For standard life-safety egress, that's a non-issue. For specialized hold times (e.g., 60 seconds to allow a loading dock door to fully cycle), you'll want to engineer around it.
Technical Highlights:
- 3-Amp DPDT Contact at 30VDC: This rating is adequate for 99% of electromagnetic strike and solenoid-lock deployments under 500 doors. On systems with multiple simultaneous releases or oversized magnetic locks, external relay isolation prevents contact chattering and extends switch life.
- Fixed 30-Second Timer Output: No user adjustment, no field programming. The timer begins on button press and holds the DPDT contact for exactly 30 seconds. Clean, deterministic behavior in every deployment; no software surprises or battery backup complexity.
- Dual Voltage (12/24 VDC ±10%): Accommodates legacy 12V systems and modern 24V distributions. We've run 413MNU units on regulated 24V UPS-backed supplies in healthcare facilities; the ±10% tolerance band provides margin for voltage sag during door operator peak draw.
- NFPA-Compliant Signage and Button Geometry: The green 2-inch lens is immediately recognizable as a life-safety control. ADA height and reach requirements are straightforward to meet; faceplate width (1¾") fits standard rough-in openings in drywall and concrete block.
- Stainless Steel 20-Gauge Frame: We've observed zero corrosion on units installed in humid (hospital) and salt-spray (coastal institutional) environments. The button cap and lens resist UV fading and chemical cleaning agents commonly used in healthcare and food-service facilities.
Deployment Considerations:
- Verify electromagnetic strike or solenoid-lock draw before installation. A 3-amp contact will chatter and degrade prematurely if asked to hold a 4-amp+ load; external relay isolation is inexpensive insurance on high-current systems.
- The 6-inch factory lead wire is designed for rough-in cutout wiring. On retrofit installations where the exit switch is mounted remote from the strike power supply, plan for a junction box or terminal strip midway; do not stretch leads beyond 10 feet without intermediate terminal blocks.
- Test the 30-second timer output in the field before final turnover. Confirm that the door release mechanism (strike solenoid, magnetic lock deactivation, or door operator) fully cycles within the 30-second hold window. If hold time is insufficient, deploy an external time-delay relay module upstream.
- In multi-door access control systems, the 413MNU functions as a hardwired secondary release point independent of the main access controller (keycard reader, biometric, etc.). This provides a fail-safe egress path if the networked access system is offline — a critical Life Safety requirement in healthcare, detention, and institutional facilities.
- Button activation is fully mechanical (no electronic debounce or software handling). High-frequency presses (e.g., children playing with the button) do not degrade the relay or timer output; each press restarts the 30-second hold cycle.
The 413MNU is the right choice for facility managers and integrators who prioritize egress reliability over feature complexity. Specify it for hospitals, schools, offices, retail, and hospitality environments where the exit switch is a life-safety critical component. For advanced programmable timing, networked credential validation, or multi-factor egress control, evaluate access controllers with integrated software timers. For straightforward hardwired door release, the 413MNU sets the standard. Explore more SDC hardwired access control products in the SDC catalog.
