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A magnetic lock is the only electrified locking device with no moving parts. No solenoid, no bolt, no keeper. Just an electromagnet bonded to a steel armature plate through electromagnetic attraction. That simplicity makes maglocks extremely reliable in high-cycle commercial applications, but it also means specification errors cannot be corrected in the field. The holding force is fixed. The mounting geometry is fixed. The fail mode is fixed at the factory.

How Magnetic Locks Work

An electromagnetic lock consists of two components: the magnet body, which mounts on the door frame or header, and the armature plate, which mounts on the door itself. When energized, direct current flows through a coil generating a magnetic field that attracts the armature plate with a controlled force measured in pounds of holding strength. The critical mechanical requirement is a gap of less than 1/8 inch between the magnet face and the armature plate when the door is fully closed. A 1/4-inch gap can reduce effective holding force by 30 to 50 percent from rated specification. When power is interrupted by an access control signal, a fire alarm relay, or a power outage, the electromagnetic field collapses instantly and the door is free to open.

Holding Force: 600 lb vs 1,200 lb vs 1,500 lb

The common error is defaulting to the highest available holding force. On a lightweight interior door with a standard door closer, a 1,200-pound magnet creates jarring release behavior in environments like healthcare corridors or hotel lobbies. The electromagnetic lock selection at National Lock Supply covers 600-pound through 1,500-pound configurations across single and double door applications.

Fail-Safe Operation and Code Compliance

Magnetic locks are fail-safe by fundamental design: power off equals door unlocked. NFPA 101 Life Safety Code requires that doors on required egress paths allow free egress without a key, tool, special knowledge, or special effort. An energized magnetic lock holding a door closed does not satisfy this requirement unless three conditions are met simultaneously.

First, a sensor monitors the egress path. A passive infrared (PIR) sensor must detect an approaching occupant and de-energize the maglock to allow egress without requiring the occupant to interact with any device. Second, a Request-to-Exit (REX) device must be present at the door. Third, the fire alarm system must be integrated so the maglock releases automatically on any fire alarm signal in the building. None of these are optional enhancements. They are code requirements for maglocks on egress paths.

Single vs Double Door Configurations

Single-door maglocks mount with the magnet body on the frame header or stop and the armature on the door face. Double door configurations require either two separate magnets, one per leaf, which is the most reliable approach; a single wide magnet body spanning both leaves; or a single magnet on the active leaf with flush bolts securing the inactive leaf. For outswing or offset doors where the magnet cannot mount directly on the header, the wall-mounted maglock line positions the magnet body against the door face using L, LZ, or Z-brackets.

Mounting Brackets

L-bracket is used on outswing doors where the magnet mounts on the doorstop projecting perpendicular to the frame. LZ-bracket combines the L-bracket with a Z-offset to compensate for doors that close slightly past flush with the frame, which is common on aluminum storefront frames. Z-bracket provides offset in one plane only for repositioning the armature plate. Aluminum storefront frames typically require a reinforcement plate inside the frame to prevent flexion under magnetic load.

Voltage and Current: 12VDC vs 24VDC

At equal power, 12VDC units draw more current and generate more heat. In installations with multiple maglocks sharing a power supply, 24VDC is preferred because lower current draw reduces heat buildup across the system. Power supply sizing must account for inrush current, which is 2 to 3 times the steady-state draw for the first 10 to 50 milliseconds when a maglock is first energized. The access control power supply selection includes units rated for maglock inrush without nuisance tripping. Standard practice is to size the power supply at 150 to 200 percent of calculated steady-state load.

REX Integration

A Request-to-Exit device is not optional. It is the mechanism that allows authorized egress from the secure side without an access credential. PIR motion sensors detect approaching occupants and release the maglock before the person reaches the door, which is the method required by most code interpretations for free egress on required exit paths. A door position switch confirms door state and prevents held-open alarms at the access control panel. The REX device selection guide covers sensor types, mounting positions, and compatibility with maglock circuits.

Top Brands

Securitron (ASSA ABLOY) is the most widely specified maglock brand in institutional and government applications. The M32 covers 600-pound applications and the M62 covers 1,200-pound. DynaLock has strong presence in medium-security commercial applications with reliable temperature performance. SDC offers a broad line with strong fire alarm integration and UL listings across the entire range. RCI 8310 and 8311 series are workhorses in commercial access control integrations. Locknetics compact form factor maglocks are frequently specified in retrofit applications where header space is limited.