Electromagnetic locks — commonly called maglocks — are one of the most reliable and widely used locking devices in commercial access control systems. They have no moving parts, no latch bolts, and no mechanical wear points. When powered, an electromagnet holds a steel armature plate with hundreds of pounds of force. When power is cut, the door releases instantly.

This guide covers everything a facility manager, system integrator, or security consultant needs to know about selecting, installing, and maintaining electromagnetic locks for commercial buildings.

How Electromagnetic Locks Work

An electromagnetic lock consists of two components:

1. Electromagnet — mounted on the door frame (header). Contains a coil of wire wound around an iron core. When DC current flows through the coil, it generates a strong magnetic field.
2. Armature plate — mounted on the door. A flat steel plate that is attracted to and held against the electromagnet when the magnetic field is active.

The bond between the electromagnet and armature plate creates holding force measured in pounds (lbs) or Newtons (N). As long as current flows, the door remains locked. The moment current is interrupted — by an access control reader, exit button, fire alarm, or power failure — the magnetic field collapses and the door swings freely.

There are no mechanical parts that engage or disengage. This simplicity is the maglock’s greatest advantage: nothing to jam, nothing to align, nothing to wear out.

Holding Force Selection

Choosing the correct holding force is the most important specification decision. Undersized locks compromise security. Oversized locks add unnecessary cost.

Standard Holding Force Options

Model	Holding Force	Typical Application
Mini maglock	120–300 lbs (530–1,330 N)	Interior cabinet doors, lightweight access panels
Standard maglock	600 lbs (2,670 N)	Standard interior doors, office doors, corridor doors
Heavy-duty maglock	1,200 lbs (5,340 N)	Exterior doors, high-security areas, heavy doors
Double maglock	2 × 600 lbs or 2 × 1,200 lbs	Double doors (one maglock per leaf)

Selection Guidelines

600 lb maglocks are sufficient for the vast majority of commercial interior doors — offices, corridors, stairwells, conference rooms, and utility closets. They hold standard-weight doors (up to 200 lbs / 90 kg) securely against normal force.

1,200 lb maglocks are required for:

• Exterior doors exposed to wind load
• Heavy fire-rated doors (steel, rated 60–120 minutes)
• High-security areas where forced entry resistance is critical
• Doors wider than 42 inches or heavier than 200 lbs

Rule of thumb: If in doubt, choose 1,200 lbs. The cost difference between 600 lb and 1,200 lb models is typically $15–$30, but the security improvement is significant.

Fail-Safe vs. Fail-Secure: Understanding the Difference

This is the most commonly misunderstood concept in lock selection, and getting it wrong has serious safety and compliance implications.

Fail-Safe (Electromagnetic Locks)

Definition: The lock UNLOCKS when power is lost.

All standard electromagnetic locks are fail-safe by nature. When the power supply is interrupted — whether by a deliberate signal, a power outage, or a fire alarm — the electromagnet de-energizes and the door releases.

Why fail-safe matters

• Building codes require fail-safe locks on egress doors so that occupants can exit during power failures and fire emergencies
• NFPA 101 (Life Safety Code), IBC (International Building Code), and local fire codes mandate this behavior on exit paths
• In Singapore (SS 536), Malaysia (UBBL), Thailand, the Philippines, and Indonesia, fire authorities enforce similar requirements

Critical safety point: Electromagnetic locks must be connected to the fire alarm system. When the fire alarm activates, all maglocks on egress paths must release immediately — no exceptions.

Fail-Secure (Electric Strikes, Electric Bolts)

Definition: The lock REMAINS LOCKED when power is lost.

Electric strikes and electric bolt locks are fail-secure. They use power to unlock, so loss of power keeps the door locked. These are appropriate for:

• Interior doors that must remain locked during power outages (server rooms, evidence rooms, armories)
• Doors that are not on egress paths
• Correctional facility doors

Key distinction: You cannot make an electromagnetic lock fail-secure. If your application requires fail-secure behavior, use an electric strike or electric bolt — not a maglock.

Installation Considerations

Mounting Configurations

Surface mount (most common): The electromagnet mounts on the frame header, armature plate mounts on the door face. Visible hardware. Fastest installation — typically 30–60 minutes per door.

Shear lock (concealed): The maglock body is recessed into the door frame, and the armature plate is recessed into the top edge of the door. Hidden from view. Requires routing/cutting into the frame and door. Best for aesthetic-sensitive installations.

Gate mount: Z-bracket or L-bracket adapters allow maglocks to be mounted on inward-swinging or outward-swinging gates. Common for perimeter gates and parking access.

Door and Frame Requirements

• Door must close fully and consistently. Maglocks require the armature plate to make flush contact with the electromagnet. Warped doors, sagging hinges, or misaligned frames will reduce holding force dramatically.
• A door closer is mandatory on every maglock-equipped door. Without a closer, the door will not return to the locked position after someone passes through.
• Frame material must support the maglock weight (2–8 kg depending on model) and mounting screws. Aluminum frames may require through-bolts rather than self-tapping screws.

Wiring

• Standard power requirement: 12V DC or 24V DC, typically 300–500 mA
• Use a dedicated power supply or the power output from an access control panel
• Route wiring through the door frame to the maglock. Use concealed conduit for clean installation.
• Install a door position sensor (magnetic reed switch) to monitor door state — open, closed, held open, forced open
• Wire the fire alarm relay into the maglock power circuit as a normally-closed contact. When the fire alarm activates, the relay opens and cuts power to all maglocks.

Common Installation Mistakes

1. No door closer installed — door stays open after entry, maglock never re-engages
2. Armature plate misaligned — even 2mm offset reduces holding force by 30–50%
3. Fire alarm not wired — code violation and life safety hazard
4. Inadequate power supply — voltage drop over long cable runs causes weak holding force
5. No request-to-exit (REX) device — occupants cannot exit without breaking the magnetic bond, creating a trapped egress situation

Accessories and Supporting Hardware

Every maglock installation requires supporting components:

Accessory	Purpose
Door closer	Returns door to closed/locked position automatically
Request-to-exit button	Allows occupants to release the lock from inside
Motion sensor (REX)	Hands-free exit detection for ADA/accessibility compliance
Door position sensor	Monitors open/closed state, triggers alarms
Z/L bracket	Adapts mounting for inward-swing or offset conditions
UPS / battery backup	Maintains lock power during short outages (optional for security)
Power supply (12V/24V DC)	Dedicated regulated power to the maglock

Maintenance

Electromagnetic locks require minimal maintenance — one of their key advantages over mechanical locks.

Monthly

• Visually inspect armature plate contact surface for debris, rust, or damage
• Wipe contact surfaces with a dry cloth (no lubricant — oil reduces holding force)
• Verify door closer operation — door should close fully and latch magnetically

Quarterly

• Test holding force with a force gauge if available, or verify by attempting to pull the door while locked
• Test fire alarm release — activate fire alarm and confirm all maglocks release
• Test request-to-exit button and motion sensor operation
• Check battery backup (if installed) — run a discharge test

Annually

• Inspect all wiring connections for corrosion or looseness
• Verify power supply output voltage under load
• Review access control event logs for patterns of “door forced open” or “door held open” alarms — these may indicate hardware degradation
• Replace door closer if closing speed has degraded or if the door no longer latches consistently

Fire Code Compliance

Electromagnetic locks on egress doors must comply with fire and building codes. Non-compliance is not a minor infraction — it is a life safety violation that can result in fines, forced closure, or criminal liability in the event of an incident.

Universal Requirements

1. Fire alarm release: Maglocks must release upon fire alarm activation. Wired through the fire alarm panel’s normally-closed relay.
2. Request-to-exit: A clearly marked exit button or motion sensor must be provided on the secure side of every maglock-equipped door.
3. 15-second rule (NFPA 101): If a maglock is on a door in a means of egress, it must release within 15 seconds of a person pushing on the door, OR it must release upon fire alarm activation and loss of power. Most jurisdictions accept the fire alarm + REX button approach.
4. Signage: Doors with maglocks may require signage indicating “PUSH TO EXIT” or showing the exit button location.

Southeast Asia Specific

• Singapore (SCDF / SS 536): All maglocks on escape routes must release on fire alarm and power failure. Annual inspection required.
• Malaysia (UBBL 1984 / BOMBA): Fire doors must not be impeded by access control. Maglocks allowed with fire alarm integration.
• Thailand (Building Control Act): Similar requirements — fire alarm integration mandatory for doors on evacuation routes.
• Philippines (Fire Code RA 9514): Bureau of Fire Protection requires exit doors to be openable without keys or special knowledge during emergencies.

Electromagnetic Lock vs. Electric Strike: When to Use Each

Factor	Electromagnetic Lock (Maglock)	Electric Strike
Operation	Fail-safe (unlocks on power loss)	Fail-secure (locks on power loss)
Moving parts	None	Yes (strike jaw)
Holding force	600–1,200 lbs	1,000–2,000 lbs
Door type	Any (surface-mounted)	Must have latch bolt (mechanical lock required)
Aesthetics	Visible on frame header	Concealed in door frame
Fire door suitability	Yes, with fire alarm integration	Yes, but check fire-rated strike availability
Installation complexity	Low	Medium (must cut frame for strike body)
Cost	$40–$120	$30–$200

Use maglocks when you need simple, reliable, fail-safe locking with no mechanical lock on the door.

Use electric strikes when you need the door to remain locked during power failures, or when aesthetics require concealed hardware.