What This Article Covers — and Who Needs It
Fail-secure electric strikes on fire-rated openings are one of the most compliance-sensitive hardware decisions in commercial construction. Contractors, security integrators, and facility managers routinely get the strike itself right — fail-secure, fire-listed, correct voltage — and then leave money and code compliance on the table by under-specifying the monitoring output. This article explains what latchbolt and cam monitoring actually does, why it gets dropped from submittals, and what the downstream consequences look like at inspection and during annual fire door audits.
What Is a Fail-Secure Electric Strike — and Why Fire Ratings Depend on It
An electric strike replaces a conventional fixed keeper in the door frame. The keeper pivots or retracts when the access control system sends power, releasing the latchbolt so the door can be pulled open from the secured side. In a fail-secure configuration, the default mechanical state is locked: the keeper holds the latch when power is removed. When power is applied, the door can be opened.
This behavior is the reason fail-secure electric strikes can carry a fire listing. During a fire alarm event, the building control system drops power to most electrified hardware. Because the fail-secure strike locks — rather than releases — on power loss, the latchbolt remains positively engaged in the keeper. The door stays latched. The fire assembly performs as rated.
Fail-safe electric strikes cannot be used on fire-labeled openings. When power drops on a fail-safe device, the keeper releases and the door is no longer positively latched — which is a direct violation of NFPA 80 requirements for fire door assemblies. If you are specifying or installing an electric strike on any door with a fire rating label, the device must be fail-secure and must carry a fire listing for the rating required at that opening.
The Monitoring Feature That Disappears at the Submittal Stage
High-specification electric strikes — particularly those designed for fire-rated and high-security openings — include an auxiliary switch that reports device status back to the access control panel. This is commonly described as latchbolt and cam monitoring, or LCBMA (latchbolt, cam, bolt monitoring with auxiliary switch).
Here is what that monitoring actually tells the system:
- Latchbolt position: Is the latch fully extended and engaged in the keeper? A retracted or short-thrown latch means the door is not positively latched — a fire door failure condition and a security gap.
- Cam position: Has the keeper moved to its energized (released) position? This confirms whether the strike actually responded to the unlock command — not just that voltage was sent.
- Auxiliary switch output: A dry-contact signal the panel can use for alarm, logging, or door-held-open events.
Together, these outputs give the access control panel — and the facility — real-time confirmation that the opening is secured as expected. Without them, the panel knows it sent a command. It does not know whether the hardware responded correctly.
Why Monitoring Gets Removed — and Why That Decision Costs More Later
Monitoring outputs add complexity to the wiring diagram and sometimes to the door prep. During value engineering, or when a submittal is rushed, the monitoring auxiliary switch gets treated as an optional feature rather than a functional requirement. Here is where that reasoning breaks down:
At the Annual Fire Door Inspection
NFPA 80 requires annual inspection of fire door assemblies. One of the conditions inspectors check is positive latching — whether the latchbolt fully engages the strike when the door is closed. On an access-controlled opening without monitoring, that check is done manually: close the door, pull on it, observe. On an opening with latchbolt monitoring wired to the panel, the facility can pull a status log that shows every instance the door closed without a fully engaged latch over the past twelve months. That is a fundamentally different level of documentation — and documentation increasingly expected by Authorities Having Jurisdiction (AHJs) on institutional projects.
At the Security Integrator Punch List
Access control panels in healthcare facilities, school buildings, and multi-tenant commercial projects increasingly include alarm logic that flags door-held-open or door-forced-open events. Without a monitoring output at the strike, the panel cannot distinguish between a door that closed but did not latch and a door that is propped open. Those are different problems with different responses. Wiring in monitoring after the opening is finished — cutting into a prepped hollow metal frame, fishing additional conductors through a power transfer device — is significantly more expensive than specifying it on the front end.
In Industrial and Retail Replacement Projects
Facilities that are upgrading existing electric strikes to fire-rated, fail-secure devices often discover that the original strike had no monitoring output. If the replacement device includes an auxiliary switch and the wiring is not extended to the panel, the monitoring feature sits unused. The hardware cost is paid; the operational benefit is not captured. For maintenance teams managing multiple controlled openings across a warehouse, distribution center, or retail portfolio, that unused monitoring output represents a recurring labor cost during every manual audit cycle.
How Power Gets to a Fire-Rated Electric Strike — and Why That Affects Monitoring Wiring
On a hollow metal frame, the electric strike is mounted in the frame. Power comes from the access control panel through conduit to the frame — typically entering through a junction box or raceway prep the frame manufacturer machines at the factory. For fire-rated openings, the frame prep and any conduit penetration must not compromise the fire rating of the assembly.
Monitoring conductors — the wires carrying the auxiliary switch signal back to the panel — run alongside the power conductors. On a properly prepped opening, these are planned into the raceway at the frame order stage. On a retrofit or field-modified opening, they are often the detail that gets forgotten until a technician is standing at the frame with a wiring diagram that calls for more conductors than the conduit was sized to carry.
If you are specifying a fire-rated electric strike with full monitoring for a new opening, confirm with the frame supplier that the raceway prep accommodates the total conductor count — power in, monitoring signal out, and any door position switch wiring if that is also part of the opening specification. Trying to pull additional conductors through an undersized raceway after the frame is set in a masonry wall is a problem that could have been solved with a phone call during the shop drawing review.
Specifying the Right Strike for the Opening — Preferred Lines to Consider
When specifying fail-secure electric strikes for fire-rated openings, look for devices from manufacturers with stable platform designs and documented UL fire listings. Lines from Corbin Russwin, Sargent, and Hager offer electric strike options appropriate for rated openings, with auxiliary switch outputs available for panel integration. Confirm the fire rating of the specific device matches the rating of the labeled assembly — a 3-hour rated opening requires a strike listed for that rating, not just any fire-listed device.
DoorwaysPlus carries electric strikes and access control hardware across these preferred lines. If you are replacing an existing device and need a functionally equivalent substitute with monitoring outputs, the team can help identify compatible options from stable, service-friendly product families.
The Monitoring Conversation Belongs at the Hardware Schedule Stage
By the time a fire-rated electric strike is being installed, most of the decisions that determine whether monitoring is practical — frame prep, conduit sizing, panel programming — have already been made. The monitoring conversation needs to happen when the hardware schedule is being written and when the frame order is being placed, not at the field inspection or the close-out punch list.
For contractors bidding access-controlled openings on fire-rated doors: confirm fail-secure configuration, verify the fire listing for the required rating, count the conductors the monitoring auxiliary switch requires, and make sure that count is reflected in the frame prep and the panel wiring scope. That sequence prevents the most common and most avoidable rework on this type of opening.