Electric Strikes: Seven Ways They Fail in the Field
An electric strike replaces the fixed keeper in the frame and releases the latch on a signal. It is the least glamorous part of an access control system and the one that most often takes the whole opening out of service. Below are seven ways electric strikes fail on Georgia buildings, and what prevents each of them at specification time.
1. The wrong fail mode on a labeled opening
A fail-secure strike keeps the latch captive when power is removed. A fail-safe strike releases. A fire-rated door has to stay latched during a fire, so a fail-safe strike on a labeled opening defeats the assembly. Egress is solved on the inside with the exit device, not by unlocking the frame. Getting this backwards is the most consequential mistake on the list.
2. Preload the strike was never rated for
Stack pressure in an Atlanta high-rise, an aggressive closer, wind on an exterior leaf, or a pressurized corridor all push the latch into the keeper. A strike that is not rated for preload binds under that load and simply will not release, usually only during the part of the day when the building is pressurized. The symptom looks intermittent and electrical. It is mechanical.
3. A frame that cannot accept the strike specified
Narrow-stile aluminum storefront with a deadlatch needs a strike body sized for that stile, not a standard cylindrical body. Hollow metal frames need adequate depth behind the cutout and are frequently grouted solid. Wood frames need backing. Confirming the frame before ordering saves a return trip with a grinder.
4. Coastal openings you are not permitted to modify
Impact and wind-rated door assemblies on the Georgia coast are listed as complete assemblies. Cutting the frame for a strike can void that listing, which matters in Savannah and anywhere else exposed to hurricane conditions. On those openings we look at an electrified exit device or an electrified lockset that keeps the assembly intact instead of forcing a strike into it.
5. Doors that move with the season
Georgia humidity swells wood doors and softens the tolerances on everything else, and a sun-loaded aluminum leaf is a different shape at four in the afternoon than it was at eight in the morning. If the latch is only just reaching the keeper on installation day, it will miss in August. Alignment, closer adjustment and latch throw are checked at the extremes, not once in mild weather.
6. Power that is not what the strike expects
Direct current and alternating current are not interchangeable, and a unit built for one will buzz, run hot or fail on the other. Beyond that, inrush current is far higher than holding current, long home runs drop voltage, and a supply sized for the coil count on paper often is not sized for them all releasing at once. Summer storms add a surge path through the same conductors, so suppression across the coil and at the supply is part of the design.
7. Monitoring the door instead of the latch
A door position contact tells you the leaf is closed. It does not tell you the latch engaged. Those are two different facts, and on a secured opening the second one is the one that matters. Strikes with a latch monitor output let the system report the real condition, which is worth specifying on any door that carries an alarm.
The standards worth naming in a submittal
ANSI/BHMA A156.31 covers electric strikes and frame-mounted actuators. UL 1034 addresses burglary-resistant electric locking. UL 10C is the positive pressure fire test applied to door assemblies. Citing the right one keeps a submittal from bouncing.
Openings get diagnosed here, not guessed at. Reach KSEDCO on (888) 360-0035, or tell us what the door is doing. Ongoing coverage falls under service and repair.