What This Article Covers and Who It Helps
This guide explains the monitoring outputs built into fire-rated electric strikes—specifically the latchbolt monitor and locking cam monitor found on heavy-duty units used in institutional, healthcare, and high-security commercial openings. If you are a contractor commissioning an access control system, a facility manager reviewing door position reports, or a specifier writing a hardware set for a rated corridor door, this piece addresses a problem that surfaces late in nearly every project: the auxiliary switch was installed, but nobody configured the system to use it.
What Is a Latchbolt Monitor on an Electric Strike?
An electric strike replaces the standard flat strike plate in the door frame. When energized (or de-energized, depending on fail mode), its keeper pivots to release the latch so the door can be pushed open without turning a handle from the outside. A basic strike does one thing: release and hold. A strike with latchbolt monitoring adds an auxiliary output—a built-in switch circuit—that reports whether the latchbolt is actually seated in the keeper at any given moment.
A locking cam monitor (found on higher-specification units) goes one step further: it confirms whether the cam mechanism that holds the keeper closed is in the locked position, independent of whether the latch itself is present. Together, these two outputs give the access control panel—and the facility—a real-time picture of whether a door is truly secured, not just whether power was sent to the strike.
Why the Monitoring Output Gets Skipped
The most common pattern on commercial projects goes like this:
- The hardware schedule specifies a fire-rated electric strike with monitoring.
- The strike ships with the auxiliary switch terminals present.
- The low-voltage subcontractor wires the strike for power and egress release only.
- The monitoring terminals are left unwired because the access control panel scope did not explicitly call for them.
- Weeks after move-in, the facility manager sees repeated “door open” or “door unsecured” alerts—or, worse, sees no alerts when a door has been propped.
This is not a wiring error in the traditional sense. It is a scope gap. The hardware specification included the monitoring feature; the installation scope did not connect it. On a rated opening, that gap has life-safety consequences.
The Fire Door Compliance Angle
NFPA 80 requires that fire door assemblies be maintained in a condition that provides positive latching at all times the door is closed. A fire-rated electric strike is listed for use on rated openings specifically because its fail-secure configuration maintains the latch engagement when power is lost. But the listing assumes the door is actually latching—and on a busy corridor door in a school, hospital, or industrial facility, that assumption breaks down faster than anyone expects.
Common real-world unlatching scenarios on rated openings:
- A cart or gurney deflects the door before the latch seats, leaving the strike keeper holding nothing.
- A worn latch bolt no longer extends fully into the keeper.
- The door closer is adjusted too fast, causing the door to bounce off the frame before latching.
- Housekeeping staff prop the door and then close it partially without confirming the latch clicked.
Without a connected latchbolt monitor, none of these conditions triggers an alert. The access control log shows the door as “secure” because the last credential event was a valid unlock-relock cycle. The latch was never confirmed.
When a fire marshal or AHJ walks the building and pulls the report, an unmonitored fire door on an access-controlled opening is a finding. Connecting the auxiliary switch turns a passive hardware feature into an active compliance tool.
Fail-Secure and Why It Matters for Fire Listings
Only fail-secure electric strikes are permitted on fire-rated openings. The distinction is fundamental:
- Fail-secure: Default state is locked. Power applied releases the keeper. Loss of power—including a fire alarm power drop—returns the strike to its locked, latching position. Egress is always free because the occupant uses the mechanical handle to retract the latch from the inside.
- Fail-safe: Default state is unlocked. Loss of power releases the keeper entirely. This destroys positive latching on a rated opening and cannot receive a fire listing for use on labeled assemblies.
When a strike carries a 3-hour fire rating and a fail-secure designation, the listing covers the hardware. What the listing does not cover is whether the installed system is actually using the monitoring outputs to confirm latching. That is an operational and commissioning responsibility.
How the Monitoring Outputs Work in Practice
The auxiliary switch on a monitored electric strike typically provides a dry-contact output—a normally open or normally closed circuit that changes state based on latch position. The access control panel, alarm panel, or building automation system reads this contact to determine door status independent of any power command sent to the strike.
On units that include both latchbolt and locking cam monitoring, the two outputs can be wired separately, giving the panel two distinct alarm conditions:
- Latch not present: The door is closed but the bolt is not seated—typically a mechanical problem or a prop condition.
- Cam not locked: The keeper is not in its secured position even though the latch may be partially engaged—a more nuanced security and maintenance indicator.
Some access control systems can use these inputs to generate work orders automatically. In a healthcare environment where life-safety inspection records are audited, having a timestamped log of every unlatched-door event on a fire corridor is a defensible compliance record. In a school, it supports forced-entry detection at perimeter openings without adding a separate door contact.
What Specifiers and Contractors Should Confirm Before Closeout
Before a project with fire-rated monitored electric strikes reaches substantial completion, confirm the following:
- The monitoring terminals are wired to the access control panel, not capped.
- The panel input point is programmed and labeled correctly for each door.
- A supervised alarm is configured so that a wiring fault on the monitoring circuit triggers an alert—not silence.
- The commissioning checklist includes a physical test: close the door without latching it and confirm the panel reports the unlatched condition.
- The fire door inspection records identify which doors have electronic monitoring and note the panel point reference for the inspector.
Specifying Monitored Electric Strikes: What to Look For
When selecting a fire-rated electric strike for an access-controlled opening, the hardware specification should call out monitoring capability explicitly. Key attributes to confirm:
- Fail-secure operation with a fire rating appropriate to the door assembly (20-minute, 45-minute, 90-minute, or 3-hour)
- Auxiliary switch type and output configuration (latchbolt only, or latchbolt plus locking cam)
- Voltage compatibility with the installed power supply (12V or 24V DC)
- Finish matching the door hardware schedule
- Compatibility with the existing frame prep or willingness to modify the frame cutout
DoorwaysPlus carries fire-rated electric strikes suitable for mortise lock applications on hollow metal frames in institutional, healthcare, and commercial settings. If you are evaluating alternatives or need a monitored strike that fits an existing frame prep, the team can help match the product to the opening.
The Bottom Line for Facility Teams
The monitoring feature on a fire-rated electric strike is not a premium add-on—it is the mechanism that bridges the gap between access control and life-safety compliance. Specifying a monitored strike and then leaving the outputs disconnected is the hardware equivalent of installing a smoke detector without connecting it to the panel. The device is present. The protection is not.
If your facility has fire-rated access-controlled openings and you are not certain whether the monitoring outputs are active, that is worth confirming before the next inspection cycle—not after.