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Four electrified hardware types integrate with access control systems: electric strikes (frame-side device releasing the latch), electric latch retraction exit devices (EL/QEL, retracting the latch inside the door), electrified mortise or cylindrical locks (electrified lever control), and electromagnetic locks (power-to-lock). Key rules: electric strikes on fire-rated doors must be fail-secure. Stairwell reentry requires fail-safe electrified hardware, but fail-safe electric strikes cannot be used on fire doors. EL uses a solenoid; QEL uses a quieter motor and should be specified for high-cycle and noise-sensitive applications. Use 12V DC for runs under 100 feet; 24V DC for longer runs. Never install an electric strike and EL device on the same opening. Request to exit (RX) switches are required on access-controlled egress doors to distinguish legitimate exits from forced entry.
Every access control project involves at least one decision about electrified door hardware, and that decision has code, fire safety, and security consequences that a wrong choice cannot easily fix after installation. The fail-safe vs fail-secure choice determines whether a door unlocks or stays locked during a power failure. The stairwell reentry rule eliminates fail-safe electric strikes from fire-rated stair doors entirely. The EL vs QEL choice affects daily noise levels in noise-sensitive facilities for years. Getting these right at specification time prevents costly retrofits and code citations.
For OEM electrified hardware parts at SecurityParts.com, browse Von Duprin 5100, 6100, 6200, and 6300 Series electric strike parts, Von Duprin EL and QEL exit device parts, Schlage electrified cylindrical lock parts, and Schlage electrified mortise lock parts.
The Four Electrified Hardware Types and When Each Is Used
How it works
An electric strike replaces the fixed strike plate in the door frame. A moving keeper inside the strike body either holds the latch bolt secure (locked) or pivots out of the way to allow the latch bolt to pass through (unlocked). Electricity controls the keeper position. The lock on the door side remains fully mechanical: the person inside can always retract the latch by turning the lever or pushing the exit device push bar, regardless of whether the strike is powered.
When to specify
Electric strikes are the correct choice when adding access control to a door that already has a cylindrical or mortise lock, when frame cutting is acceptable, or when the opening does not have an exit device and frame-side control is sufficient. They are the most economical electrified hardware option. Von Duprin's 5100 Series covers standard commercial cylindrical and mortise applications. The 6100 is heavy-duty. The 6200 provides high-security fail-secure performance. The 6300 covers the widest lock compatibility range.
When NOT to specify
Do not install an electric strike on the same opening as an EL or QEL device: this creates a redundant and failure-prone system. Do not specify a fail-safe electric strike on a fire-rated door: fire doors must be positively latched, which requires fail-secure strikes. Do not use an electric strike for stairwell reentry on a fire-rated door for the same reason.
Browse Von Duprin 5100, 6100, 6200, and 6300 Series electric strike parts at Security Parts.
How EL works
Electric Latch Retraction (EL) is a function available on Von Duprin exit devices (98/99, 22, 33A/35A, and related series) where a solenoid inside the device body retracts the latch bolt when powered. When the access control system signals the door to open, the solenoid activates, pulling the latch to the retracted position. The door then opens freely as push-pull without anyone pressing the push bar. The push bar always provides mechanical egress regardless of power state.
How QEL is different
QEL (Quiet Electric Latch Retraction) replaces the solenoid with a motor-driven mechanism. The motor actuates much more quietly than a solenoid. QEL also provides features not available on EL: troubleshooting diagnostics, automatic calibration, a retry mode that automatically reattempts retraction if the first attempt fails, and vandal resistance detection that signals the access control panel if the push bar is subject to sustained impact.
When to specify QEL over EL
QEL is the correct specification for hospitals, healthcare corridors, libraries, museums, classrooms, theaters, and any noise-sensitive environment. Also specify QEL on any high-cycle door (500 or more cycles per day) because the motor mechanism has longer cycle life than the solenoid-based EL under continuous high-cycle conditions.
Browse Von Duprin EL and QEL electrified exit device parts at Security Parts.
How it works
An electrified mortise or cylindrical lock is a standard mechanical lock that has been modified with an electrical component that controls whether the outside lever can be operated. In the electrically locked (EL) configuration, power must be applied to unlock the outside lever. In the electrically unlocked (EU) configuration, power must be applied to lock the outside lever. The inside lever always operates freely, providing egress regardless of power state.
When to specify
Electrified mortise and cylindrical locks are the correct choice when access control is needed at a standard corridor or entry door without an exit device, when the latch mechanism itself should be controlled rather than the strike, when fail-safe operation is required on a non-fire-rated door (fail-safe electromechanical locks are used for stairwell reentry), or when an electrified mortise provides a cleaner aesthetic than a strike-based solution.
Key limitation
Electrified mortise and cylindrical locks cannot be used with automatic operators because the latch is not retracted until someone turns the lever. If an automatic operator opens the door before the lever is turned, the latch will interfere with the opening. For automatic operator applications, an electric strike or EL/QEL device is required.
Browse Schlage L Series electrified mortise lock parts and Schlage ND Series electrified cylindrical lock parts at Security Parts.
How it works
An electromagnetic lock (maglock) is an electromagnet mounted on the door frame with a steel armature on the door. When power is applied, the magnet bonds to the armature with substantial holding force. When power is cut, the bond releases and the door opens. Electromagnetic locks are power-to-lock devices: they are always fail-safe. There is no mechanical locking component: the bond is purely electromagnetic.
Critical limitations
Electromagnetic locks are only fail-safe. There is no fail-secure electromagnetic lock. This makes them unsuitable for fire-rated doors (which require positive latching, not electromagnetic bonding) and for most secured perimeter applications where the door must remain locked during a power failure. Maglocks are appropriate for controlled access doors in non-fire-rated applications where the fail-safe characteristic is acceptable or required, such as interior access control doors or elevator lobbies.
Fail-Safe vs Fail-Secure: The Decision Framework
This is the decision that determines whether a door creates a security risk or a safety hazard when power fails. There is no universal correct choice: the selection depends on the door's location, fire rating, life safety code requirements, and occupancy.
The Stairwell Reentry Rule: The Most Common Fail-Safe vs Fail-Secure Specification Error
Most building codes (IBC and NFPA 101) require stairwell doors to allow reentry from the stair back into the building during a fire. This means the stair side lever must unlock during a fire alarm. This requires fail-safe hardware on the stair side. However, stairwell doors are fire-rated doors, which must be positively latched at all times.
This creates an apparent conflict: the door must be fail-safe for reentry (unlocking on alarm) and fail-secure for the fire rating (positively latched during a fire). The resolution: fail-safe electrified lever trim for fire exit hardware maintains the positive latch (the EL mechanism keeps the latch bolt projected) while providing fail-safe outside lever control (the lever unlocks when power is cut). A fail-safe electric strike alone cannot satisfy both requirements because a fail-safe electric strike does not maintain positive latching when power is cut.
Von Duprin Electric Strike Series at Security Parts
| Series | Performance Level | Key Feature | Voltage | Primary Application |
|---|---|---|---|---|
| 5100 Series | Medium duty | Dual voltage, selectable fail mode | 12V / 24V DC | Standard commercial cylindrical and mortise lock applications |
| 6100 Series | Heavy duty Grade 1 | Broader lock compatibility, dual voltage | 12V / 24V DC | Heavy commercial, institutional cylindrical and mortise |
| 6200 Series | High security fail-secure | Maintained locked position during power failure; high holding force | 12V / 24V DC | High-security perimeter doors requiring fail-secure integrity |
| 6300 Series | Wide compatibility | Widest lock compatibility across cylindrical, mortise, and panic hardware | 12V / 24V DC | Mixed hardware environments; broadest application range |
Parts across all four Von Duprin electric strike series include solenoid assemblies, strike plates, cover kits, and mounting hardware. Electric strike components are not cross-compatible between series: a solenoid from the 6200 series will not fit a 6100 unit. Always order replacement parts by confirming the exact series before ordering. Browse Von Duprin electric strike parts by series at Security Parts.
Von Duprin Exit Device Electrification Options
EL: Electric Latch Retraction
Order prefix: EL (e.g., EL99L)
Solenoid retracts latch for remote access control. Audible solenoid click during activation. High inrush current at activation. Always fail-secure: latch projects when power is removed. Available on rim, SVR, CVR, and mortise configurations.
QEL: Quiet Electric Latch Retraction
Order prefix: QEL (e.g., QEL99L)Motor-driven retraction: significantly quieter than EL. Computer features: diagnostics, auto calibration, retry mode, vandal detection. Lower and more consistent current draw. Specify for noise-sensitive applications and high-cycle (500+ cycles/day) openings.
RX: Request to Exit Switch
Order suffix: RXDry contact switch signals access control panel when push bar is pressed. Distinguishes legitimate egress from forced entry for alarm management. Required on access-controlled egress doors. Available on 98/99, 22, 33A/35A, and related series.
LX: Latch Monitor Switch
Order suffix: LXMonitors whether latch bolt is in the projected (latched) or retracted position. Signals access control panel of latch state. Used for door status monitoring in security-sensitive applications. Combined with door position switch for complete door status monitoring.
SS: Signal Switch
Order suffix: SSDry contact that closes when the push bar or touch pad is depressed. Simpler than RX: monitors bar depression rather than latch retraction. Used when access control panel needs bar actuation signal without full RX integration.
DPS: Door Position Switch
Order suffix: DPSMonitors whether the door is open or closed, independent of the latch state. Used with RX and LX for complete access control monitoring. Enables forced door alarm when door opens without an authorized credential or push bar event.
12V vs 24V DC: Voltage Selection for Electric Door Hardware
Most Von Duprin electric strikes and electrified exit devices operate on either 12V or 24V DC, with many models field-selectable between the two. The selection is based primarily on wire run length from the power supply to the device.
Why Voltage Drop Matters
Wire resistance causes a voltage drop proportional to the wire length and the current drawn by the device. A solenoid that receives insufficient voltage activates weakly, actuates intermittently, or does not actuate at all. This produces field failures that appear random and are difficult to diagnose because the device tests fine when connected directly to the power supply (short run) but fails in the installed long-run condition.
At 24V, the same absolute voltage drop across the wire resistance removes a smaller percentage of the supply voltage at the device than at 12V. For example: a 1-volt drop in a 100-foot 16-gauge wire run takes 8.3 percent of a 12V supply but only 4.2 percent of a 24V supply. The device at the end of the 24V run receives a higher percentage of its rated voltage.
Selection Guidelines
Use 12V DC for wire runs shorter than approximately 100 feet where voltage drop is manageable, and for devices that do not offer a 24V option.
Use 24V DC for wire runs over 100 feet. Calculate the actual voltage drop based on wire gauge and run length to confirm the device receives sufficient voltage at the rated gauge before finalizing the installation.
Von Duprin Power Supplies for Electrified Door Hardware
Von Duprin PS900 series power supplies are the correct power supply for Von Duprin electric strike and electrified exit device applications. The PS900 series is sized to handle the inrush current requirements of EL solenoid devices in addition to their steady-state holding current. Using a generic 12V or 24V power supply not designed for solenoid inrush current can cause intermittent actuation failures even when the voltage output appears correct.
The PS900 series is available in 12V and 24V DC output versions and in multiple current capacities to serve different numbers of devices from a single supply. For multi-door access control systems, the power supply current capacity must accommodate the simultaneous inrush current of all devices that could activate at the same time, not just the steady-state current of all devices. Browse the Von Duprin power supply catalog at SecurityParts.com alongside the Von Duprin electric strike parts and EL and QEL exit device parts.
Request to Exit (RX) Switch: Why It Is Required on Access-Controlled Doors
A request to exit (RX) switch is built into an exit device and generates a signal to the access control panel whenever the push bar or touch pad is actuated. The access control panel uses this signal to distinguish between two events that otherwise look identical from a door position perspective: a door opening after an authorized credential has been presented from outside (normal entry), and a door being pushed open from inside (legitimate egress).
Without an RX signal, the access control system cannot tell whether a door opening represents an authorized entry or a legitimate exit. This forces the system to either generate false alarms on every legitimate exit or to disable door-forced alarms entirely. Neither outcome is acceptable in a security system.
The RX signal flow: occupant presses push bar, RX switch closes, signal sent to access control panel, panel records an egress event and suppresses a door-forced alarm for the shunt time (typically 5 to 10 seconds to allow the door to close). If the door opens without either an RX signal (egress) or a credential event (entry), the panel generates a door-forced alarm.
Browse Von Duprin exit device parts including RX, LX, DPS, and SS switch options at SecurityParts.com. For the complete Allegion electrified hardware parts catalog, browse all products at SecurityParts.com. Pre-order support at 845-935-0301 or the contact page.
Why Choose SecurityParts.com for Electrified Door Hardware Parts
Stairwell reentry code detail, EL inrush current warning, fail-safe fire door prohibition, QEL vs EL cycle life guidance, and same-day OEM shipping.
Stairwell Reentry Code Detail
We document why fail-safe electric strikes cannot satisfy stairwell reentry requirements on fire doors. This is the most common fail-safe vs fail-secure specification error and is not documented in any competitor content at the parts ordering level.
EL Inrush Current Warning
We document the EL solenoid high inrush current issue and why power supply sizing to steady-state current alone causes intermittent field failures. QEL's motor mechanism eliminates this problem with more consistent current draw.
RX Switch Function Explained
We document why RX switches are required for alarm shunting and how the RX signal distinguishes legitimate egress from forced entry. This prevents both false alarms and disabled door-forced alarms in access control systems.
Same-Day OEM Shipping
Von Duprin EL, QEL, electric strike, and access control switch parts ship same day from US warehouses. Call 845-935-0301 or use the contact page for electrified hardware compatibility support.
What Makes Security Parts Different for Access Control Hardware Parts
- We document the stairwell reentry fail-safe electric strike prohibition in detail: fail-safe electric strikes cannot provide positive latching on fire-rated stair doors, making them non-compliant for reentry on fire doors regardless of the access control requirement. This code nuance is absent from all competitor parts supplier content.
- We document the EL solenoid inrush current issue and the QEL motor mechanism advantage. Power supply failures on EL installations from undersized supplies are the most common electrified door hardware field failure and are not documented in any competitor content.
- We document the electrified lock and automatic operator incompatibility: electrified mortise and cylindrical locks cannot be used with automatic operators because the latch does not retract until the lever is turned. This requires using electric strikes or EL/QEL instead, which is never explained in standard access control hardware content.
- We document the RX switch alarm shunt function and why door-forced alarms without RX produce either continuous false alarms or disabled security monitoring. Both outcomes are security failures that the RX switch specification prevents.
- We carry Von Duprin electric strike parts, EL and QEL exit device parts, electrified mortise lock parts, and electrified cylindrical lock parts for complete access control integration in one order.
- Free shipping on orders over $450. Same-day shipping from US warehouses on stocked parts. 30-plus years of commercial door hardware experience.
Frequently Asked Questions About Access Control and Commercial Door Hardware
What is the difference between fail-safe and fail-secure electrified door hardware?
Fail-safe unlocks when power is removed. Fail-secure stays locked when power is removed. Both always provide free egress from the inside. Key rules: electric strikes on fire-rated doors must be fail-secure for positive latching compliance. Stairwell reentry requires fail-safe electrified hardware (electromechanical locks or fail-safe electrified trim for fire exit hardware) but not fail-safe electric strikes, which cannot maintain positive latching on fire doors. Electromagnetic locks are a fail-safe only.
Why can't a fail-safe electric strike be used for stairwell reentry on fire-rated doors?
Fire-rated doors require positive latching during fire events. A fail-safe electric strike releases its keeper when power is cut. Under fire pressure conditions, the spring-loaded keeper alone provides insufficient holding force, allowing the latch bolt to be pushed through and the door to open, compromising fire separation. Stairwell reentry on fire-rated doors requires fail-safe electrified lever trim for fire exit hardware or fail-safe electromechanical locks, which maintain positive latching while unlocking the outside lever on fire alarm.
What is the difference between Von Duprin EL and QEL electric latch retraction?
EL uses a solenoid: audible click during activation, high inrush current at activation, standard cycle life. QEL uses a motor-driven mechanism: significantly quieter operation, lower and more consistent current draw, longer cycle life, plus computerized features including troubleshooting diagnostics, automatic calibration, retry mode, and vandal resistance detection. Specify QEL for hospitals, libraries, healthcare, noise-sensitive environments, and any door cycling more than 500 times per day.
When should an electric strike be used instead of electric latch retraction on an exit device?
Use an electric strike when adding access control to a cylindrical or mortise lock (not an exit device), when budget is the primary constraint, or when frame cutting is acceptable. Use EL or QEL when the opening has an exit device and frame cutting must be avoided (especially on fire-rated doors where frame cuts can affect assembly listings), when fail-secure performance with the lowest frame damage risk is needed, or when the combined access control and business-hours push-pull function of EL/QEL is needed. Never combine an electric strike and EL device on the same opening.
Should I use 12V or 24V DC for electric strikes and electrified door hardware?
Use 12V DC for wire runs under approximately 100 feet. Use 24V DC for runs over 100 feet to compensate for voltage drop across wire resistance. At 24V, the same absolute voltage drop represents a smaller percentage of supply voltage, ensuring the device receives sufficient voltage for reliable actuation. For EL solenoid devices, calculate voltage drop using inrush current (not steady-state current) to confirm adequate supply voltage at the device under worst-case conditions.
What is a request to exit (RX) switch and why is it required on access-controlled doors?
An RX switch signals the access control panel when the exit device push bar is pressed. The panel uses this signal to distinguish legitimate egress (bar pressed from inside) from forced entry (door opened without credential or bar event). Without RX, the system either generates continuous false alarms on every legitimate exit or disables door-forced alarms entirely. The RX signal shunts the door-forced alarm for a set time (typically 5 to 10 seconds) after bar depression, allowing the door to open and close without generating a false alarm while maintaining security monitoring.