How do Electromagnetic Locks Work?

What Is an Electromagnetic Lock?

An electromagnetic lock (or “maglock”) secures a door using magnetic attraction. The magnet inside the unit only becomes active when electrical current is supplied. With no power, there’s no magnetic field, so the door can be opened freely. When power is present, the magnet engages and holds the door shut.

Are Maglocks Fail Safe or Fail Secure?

In electronic access control, “fail safe” and “fail secure” describe how a lock behaves when power is lost:

  • Fail safe: The door unlocks when power is removed. Power is required to keep the door secured.
  • Fail secure: The door remains locked when power is removed. Power must be applied to release it.

Electromagnetic locks are inherently fail safe, as they rely on continuous power to stay magnetised. If electricity is cut, the magnetic field drops instantly and the door releases.

Typical Applications for Electromagnetic Locks

Because they default to the unlocked position during a power outage, maglocks are often chosen for fire exits and emergency escape routes. In an emergency where electrical supply might fail, the door automatically becomes free to open.

They’re also popular for glass door installations. Timber or PVC doors can accommodate embedded locks like electric strikes, but glass leaves limited space for cutting or drilling. Maglocks solve this by mounting onto the surface using specially designed brackets.

How Do Electromagnetic Locks Function?

A maglock is made up of two key components: the electromagnet, which is usually attached to the frame, and the armature plate, fixed to the door. When power energises the magnet, a strong magnetic field pulls the armature plate towards it, keeping the door firmly closed until the power is removed.

Types of Electromagnetic Locks

Maglocks come in a range of configurations tailored to different door styles, environments, and security needs.

Indoor vs. Outdoor Use

Some models are suitable only for interior doors, while others are purpose-built for external gates and entrances. Outdoor versions are tested to IP (Ingress Protection) ratings, which assess resistance to dust and moisture.

  • The first digit (1–6) measures protection against solid particles such as dust.
  • The second digit (1–8) measures resistance to liquids, ranging from light splashes to full submersion.

High-quality external maglocks often achieve an IP68 rating, indicating maximum protection.

Surface-Mounted vs. Mortice-Mounted

Electromagnetic locks can be installed in one of two ways:

Surface-Mounted Maglocks

These units sit on top of the existing frame and door structure. Installation differs depending on whether the door is pushed or pulled:

  • Pull doors: A Z&L bracket positions the magnet on the frame and the armature on the door so the two meet correctly.
  • Push doors: The magnet is typically fixed beneath the frame head, with the armature directly on the closing face of the door.

Mortice Maglocks

Mortice units are recessed into the door and frame, keeping the hardware hidden from view. A cavity matching the size of the magnet is cut into the frame, and the armature is similarly embedded in the door leaf. These are often fitted at the top of the door but can also be integrated into the floor and bottom edge.

Monitored vs. Unmonitored

Some maglocks include monitoring sensors, which report whether the lock is engaged or disengaged. When connected to an access-control system, this allows real-time visibility of door status, which is useful for security audits and system diagnostics.

Holding Force

The holding force indicates how much pressure the magnet can withstand before the door could be forced open. It’s commonly listed in kilograms or pounds. Typical ratings include 180kg, 300kg, 400kg, and 500kg. Higher values mean stronger magnetic fields and greater resistance to forced entry.

Can You Use Electromagnetic Locks on Fire Doors?

Yes you can – provided the lock carries the appropriate fire safety certification. Maglocks are often a smart choice for fire-rated escape routes because:

  1. They contain no mechanical parts that could distort in extreme heat.
  2. Their fail-safe operation ensures the door releases instantly if the building’s power supply fails during an emergency.

Final Thoughts

Electromagnetic locks offer a reliable, low-maintenance way to secure a wide variety of door types, from internal offices and glass entrances to external gates and fire exits. Their simplicity, strength, and versatility make them a popular option for many access-control installations.

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