The Importance of Electric Strikes

Using electric strikes for access control helps keep installation costs down by working with existing doors, frames and door hardware.


Electric strikes were originally invented to allow apartment dwellers to remotely unlock vestibule doors instead of having to trudge down flights of stairs whenever a visitor came to call. Although the power source was electricity, the system was manually operated. A person would physically push a button to release the electric strike.

The majority of those early electric strike mechanisms consisted of an electro-magnet and a spring-operated gate. When current was applied to the electro-magnet, the steel gate was attracted to the electro-magnet and the electric strike was released to an unlocked position. Since the electro-magnets were not very strong, the return spring for resetting the gate to a locked position had to be weak enough to allow the magnetic field to function while having just enough spring strength to return the gate to the locked position once the flow of electricity stopped.

Since the electric source was usually alternating current (AC), the gate flapped back and forth as the current changed every second. The noise from an electric strike caused many people to refer to electric strikes as “buzzers.” A byproduct of the buzzing noise was that the life cycle of the thin gate spring was very short. Parts in most electric strikes manufactured two or three decades ago were factory-sealed with no provision for repair. Locksmiths learned to stock quantities of electric strikes because replacement was inevitable, sometimes within months of installation depending on their usage. Fortunately there were only approximately a half- dozen popular electric strike designs at the time, so not many types had to be stocked.

Electric strikes were originally designed to operate in conjunction with spring latches. When the electric strike was locked, it functioned in a way similar to a solid strike plate. The door lock latch would be forced inward as the door was closed. When the door was fully closed, spring action would move the latch into an open area behind the electric strike keeper to secure the door. Whenever the electric strike was electrically actuated, the keeper was free to fold out of the way as a person pulled outwards on the door handle. Once the keeper folded out of the way, the door could be opened even though the latch was not retracted. Most electric strikes require a cutout in the frame in order to allow the extended latch to pass through the frame as the door is opened.

 

Electric Strikes Vs. Maglocks

Electric strikes have found new life in the last decade. Increased requirements for access control have put the need for electric strikes front and center. The other competing electric locking systems are maglocks and electrified hardware. Maglocks and electrified hardware will operate very well when used in new building construction situations. However, locksmiths are often faced with aftermarket installations where the doors and frames were not originally designed for maglocks or electrified hardware. In a retrofit situation, electrified door locks may require a raceway through the door from hinge to lockset, plus added hardware is needed for connecting the electrical source from jamb to door. Panel doors or doors with panes of glass can present an obstacle to drilling raceways. Battery-operated locks can solve the raceway problem, but do require periodic maintenance for battery replacement.

The optimum location for single point security is midway between the top and bottom of the door. Maglocks are usually installed at the top of the door. When a maglock is mounted at the top of the door, it may allow a tired existing door to flex and not firmly hold the door in a fully closed position. Various local building laws also may not allow a locking system which does not have a mechanical disconnect. A new door and/or frame designed for the specific hardware to be installed is the solution to some of these issues, but this also adds to the cost of the job.

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