What This Article Covers and Who It Helps
When an electric strike is part of an access control circuit, the question of how the system knows the door is secured comes up on nearly every project. Two primary monitoring methods exist inside or alongside the strike: a latch-bolt monitor switch that detects whether the latch has actually engaged the keeper, and a cam switch that detects keeper position. Choosing the wrong type leads to nuisance alarms, missed forced-entry alerts, and audit logs that do not reflect reality. This guide is for commercial contractors, facilities managers, and security integrators specifying or troubleshooting monitored electric strike installations in schools, healthcare facilities, retail, and industrial buildings.
What Is an Electric Strike Monitor Switch?
An electric strike monitor switch is a small internal or accessory switch built into or added to an electric strike that generates a signal—typically a change in circuit continuity—to report a specific condition back to an access control panel or alarm system. That signal answers one of two different questions depending on the switch type:
- Latch-bolt monitor switch: Is the latch bolt physically seated in the strike keeper?
- Cam switch (keeper position switch): Is the strike keeper in the locked or unlocked position?
These are related but not the same thing, and conflating them is a common specification error.
The Latch-Bolt Monitor Switch
A latch-bolt monitor switch responds to the presence of the latch bolt itself pressing against a contact inside the strike pocket. When the door closes and the latch seats fully, the switch changes state. When the door opens and the latch withdraws, the switch signals that the bolt is no longer engaged.
What It Confirms
- The door is physically closed and latched—not just shut against the stop
- The latch bolt has traveled far enough to engage the keeper
- Useful as a secondary confirmation that the opening is actually secured, not merely that the striker has energized
Where It Is Valued Most
- Healthcare and behavioral health facilities where positive latching must be confirmed room-by-room for patient safety
- School buildings where corridor door status is reported to a head-end panel and doors that fail to latch trigger alerts to facility staff
- Industrial secured areas where a door dragged shut but not fully latched represents a real gap in the security perimeter
Limitation to Know
A latch-bolt switch will show a secured state any time the latch is seated—even if someone has propped the keeper open or if the strike is in a fail-safe, unpowered, released condition. It monitors the latch, not the integrity of the lock itself.
The Cam Switch (Keeper Position Switch)
A cam switch is mechanically tied to the moving keeper or plunger inside the strike body. It changes state when the keeper rotates or pivots between its locked and unlocked positions, regardless of whether a latch bolt is actually present.
What It Confirms
- The strike keeper is in the locked position—ready to hold a latch if it enters
- The keeper has been electrically actuated to the released position
- Useful for confirming that an access-granted credential event actually moved the hardware, not just that a relay fired
Where It Is Valued Most
- Access control audit trails in commercial office and retail environments where the log should confirm a mechanical unlock event, not just a card read
- Fail-secure strike configurations where confirming the keeper returned to locked after an access grant is a priority
- Integrators troubleshooting intermittent release failures—a cam switch lets the panel see whether the strike actually cycled its keeper when commanded
Limitation to Know
A cam switch in the locked position does not confirm that the latch bolt is engaged. The door could be standing open, the latch could be retracted by a lever, or the door could be pulled partially ajar. The cam switch tells you keeper state only.
Using Both Signals Together
Higher-security applications combine a door position switch (DPS) with either or both internal monitor signals to build a complete picture:
- Door position switch: door open or closed (magnetic contact at frame)
- Latch-bolt monitor: latch engaged or withdrawn
- Cam switch: keeper locked or released
This three-layer approach lets a panel distinguish between a door that is closed and latched, a door that is closed but not fully latched (latch bolt short of the keeper), and a door that appears closed on the DPS but whose keeper was never returned to locked. That granularity matters in life-safety contexts, particularly on fire-rated doors where positive latching is a code requirement and in healthcare corridors where patient safety depends on reliable status reporting.
Specifying the Right Monitor Option
When you build your hardware schedule or submit an RFI, clarify these points before ordering a monitored strike:
- What condition needs to be reported? Keeper state, latch presence, or both?
- What voltage and contact rating does the panel input require? Monitor switches are typically dry contacts; confirm normally open vs. normally closed logic with the access control integrator.
- Is the opening fire-rated? Only fail-secure electric strikes may be used on fire-labeled doors, and the monitoring circuit must not interfere with positive latching under any power condition.
- Does the product carry a fire listing for the configuration you need? Monitor options are sometimes only available on specific strike models—confirm availability before the door gets prepped.
Products to Consider
DoorwaysPlus.com carries electric strikes from HES, a well-regarded source for monitored strike options across a wide range of lock types. HES models across their 1500 Series, 5000 Series, and 9000 Series lines include optional monitor switch configurations suited to the latch-sensing and keeper-sensing applications described above. Pair a monitored strike with the correct door position switch and power supply to close the loop on your access control circuit.
For applications where the opening uses a mortise lockset—such as a Corbin Russwin ML2000 or a Sargent 8200 Series—confirm that the strike model is compatible with the mortise latch projection and that the monitor switch option is available for that strike body. Not all monitor configurations fit all lock types.
Need help matching a monitored strike to your door schedule or access control panel requirements? The team at DoorwaysPlus.com can help you work through compatibility, fail-safe vs. fail-secure requirements, and fire-listing constraints before anything ships.