A magnetic lock can look like one of the simpler parts of an access control system: apply power, the magnet holds the armature plate, and remove power to release the door. In practice, most maglock problems are caused by something around the lock rather than the magnet itself. The wrong bracket, poor alignment, an undersized power supply or an unsuitable release arrangement can turn a straightforward installation into a return visit.
The best place to start is not with a holding-force figure. Start with the door. Its construction, opening direction, location, number of leaves and required system feedback will narrow the choice quickly. This guide covers the main options available from Door Access Supplies, along with the brackets and accessories needed to complete a dependable installation.
How a maglock works
A standard maglock consists of an electromagnet fixed to the frame or header and an armature plate fitted to the door. When the lock is energised, the two faces pull together. When power is removed, the door is released.
That makes a maglock a fail-safe locking device. A loss of power unlocks the door, which is useful where safe egress is the priority, but it also means the power supply, backup strategy and release circuit need to be considered as part of the design. A maglock should never be selected in isolation from the door’s escape, fire and access-control requirements.
1. Choose the holding force for the door
Maglocks are normally described by their nominal holding force. The figures are useful for comparing products, but they are not the whole specification. Door size, construction, expected use, leverage, frame strength and fixing method all matter. The rated force also depends on the armature meeting the magnet squarely across its full face.
Compact and 300lb maglocks
Compact locks suit smaller doors, cabinets and lighter-duty applications where available mounting space is limited. They should not be treated as a smaller substitute for a commercial door lock simply because they are easier to fit. Check the intended application and the door construction first.
600lb maglocks
A 600lb maglock is a common choice for internal access-controlled doors. The ML600 slimline maglock, for example, provides a nominal 600lb (280kg) holding force in a compact surface-mounted body. It is a practical starting point for many timber, aluminium and commercial door applications, provided the door, frame and mounting arrangement are suitable.
1200lb maglocks
Heavier doors and more demanding openings may call for a 1200lb lock. This gives greater nominal holding force, but bigger is not automatically better. A larger lock needs more mounting space, suitable structural fixing and typically draws more current. Products such as the ML1200-M monitored maglock are useful where both higher holding force and lock-status feedback are required.
High-security maglocks
Some projects need substantially more holding force than a conventional 600lb or 1200lb unit. The SML-3000 high-security monitored lock is rated at 3000lb (1400kg) and has its own compatible mounting accessories. This type of lock should be specified as a complete assembly, with particular attention paid to the door structure, bracket choice and fixings.
Installer’s point: a higher holding-force number will not compensate for a flexible frame, loose fixings or an armature plate that only touches one edge of the magnet.
2. Standard, monitored or door-status monitoring?
Once the physical lock size has been decided, consider what the access control system needs to know. These options are often confused, but they serve different purposes.
Standard maglock
A standard, unmonitored maglock locks and releases when instructed, but it does not send lock-condition feedback to the controller. This can be enough for a simple standalone door where remote status reporting is not needed.
Monitored maglock
A monitored model provides an output that can be used by a compatible access control system to indicate the lock’s condition. This is useful where a controller, alarm system or building management system needs confirmation rather than simply assuming the door has locked. The monitoring output and contact rating must be checked against the receiving equipment.
Maglock with MDS
An MDS model adds door-position information as well as lock monitoring. That distinction matters: a magnet can be energised while the door is still open, and a door can be closed without the armature forming a full bond. A product such as the ML600-MDS can give the system a clearer picture of what is happening at the opening. It is a sensible choice where door-held-open alarms, status reporting or more detailed event records are required.
3. Single doors and double doors
A single-leaf door normally uses one magnet and one armature. A pair of doors may need a double maglock, with one magnet and armature for each leaf. The ML600-D double maglock provides 600lb of nominal holding force per leaf.
Treat each leaf as its own opening when checking alignment, mounting space and current consumption. On a double lock, the electrical load is normally the load of two magnets rather than one. Also check whether the leaves open together, independently or in a controlled sequence, particularly on rebated or fire-resisting door sets.
Door Access Supplies also carries matt black access control hardware for installations where the lock and brackets need to match dark frames, handles or architectural ironmongery.
4. Internal and external maglocks
An internal slimline maglock should not be fitted outside and expected to cope with rain, condensation and temperature changes. Gates, exposed entrances and external doors need a purpose-made weather-resistant lock, suitable cable entry and compatible external brackets.
For external openings, consider a stainless-steel gate lock such as the EXML600-GATE-M monitored external maglock or the heavier-duty EXML1200-GATE-M. The lock rating is only part of the job: cable routing, joints, enclosures, gate movement and mechanical stops also need to suit the environment.
5. Select the bracket from the door arrangement
Brackets are not cosmetic extras. They establish the position and angle of the magnet and armature, so the correct bracket is essential if the lock is to achieve reliable face-to-face contact. The opening direction is important, but it is not the only question. You also need to know which side the lock is being mounted on, how much head room is available, the frame profile and whether the door is timber, metal or glass.
L Brackets
An L bracket creates a suitable mounting face when the frame or header does not provide enough flat material for the magnet. It is often used on outward-opening doors or narrow aluminium profiles, and it can bring the magnet forward to line up with the armature. The bracket must match the maglock model; a 600lb bracket should not be assumed to fit a 1200lb lock.
Z&L Brackets
A Z&L set is commonly used on inward-opening doors. The L section supports the magnet at the frame, while the adjustable Z section positions the armature on the moving leaf. Adjustment is valuable during commissioning, but the armature must still retain the movement specified by the lock manufacturer so it can pull squarely onto the magnet.
U Brackets and glass-door brackets
A frameless glass door cannot be drilled or fixed like a timber or steel leaf. A compatible U bracket is used to hold the armature at the glass edge, while dedicated glass Z&L and architectural bracket sets are available for particular door arrangements. Check glass thickness, clearances and product compatibility before ordering.
Armature housings, extension plates and fixing kits
An armature housing gives the plate a neater, more protected mounting arrangement. Extension plates add usable fixing space on awkward headers, while model-specific fixing kits help secure the armature through the door correctly. These parts solve different problems; they are not interchangeable.
Browse the full range of maglock brackets and accessories alongside the maglock collection. Matching the accessory code to the lock before attending site is usually much quicker than trying to adapt the wrong bracket at the door.
6. Size the power supply properly
Because a maglock is continuously energised while the door is locked, the power supply must be sized for the total standing load. Check the lock’s current at the chosen voltage, then add the controller, reader, sounder, relay and any other powered equipment. For double doors, include both magnets. Allow suitable spare capacity rather than running the supply at its limit.
Voltage drop also matters, especially on long cable runs. Confirm the cable size, route length and terminal voltage under load. If the door must remain controlled during a mains failure, select a power supply unit with the appropriate charging capacity and pair it with correctly sized standby batteries.
7. Do not overlook the release devices
The access credential gets people in, but the safe release arrangement is just as important. Depending on the door and the agreed system design, the installation may include:
- a keypad or reader for authorised entry;
- an internal request-to-exit button or compatible sensor;
- a green emergency door-release call point in the release circuit;
- a suitable fire-alarm interface or fire-alarm activation component where required by the system design;
- a timer or relay where controlled sequencing is required; and
- a door loop where a compatible device genuinely requires power or signalling to cross onto the moving leaf.
The exact arrangement must suit the building’s fire strategy, means of escape and applicable standards. On fire-resisting doors, also confirm that the lock, brackets, fixings and installation method are supported for the particular door set. If that information is not available, pause the specification rather than relying on a generic statement that a maglock is “fire rated”.
8. When a conventional maglock is not the best answer
Surface-mounted maglocks are visible and need room at the head of the door. Where appearance, door geometry or security requirements point elsewhere, compare the application with shear locks and electric bolts or electric strikes. These products operate differently and have their own door-preparation, alignment and egress considerations, so the decision should be made at specification stage rather than after the frame has been prepared.
Common maglock selection mistakes
- Ordering the lock before checking the frame. The door arrives on site and there is nowhere suitable to mount it.
- Using the wrong bracket for the opening direction. The armature cannot meet the magnet squarely.
- Rigidly fixing the armature plate. The plate loses the small amount of movement it needs to align with the magnet face.
- Ignoring the current draw. The supply is adequate on paper for one lock but not for two locks and the rest of the system.
- Using an internal product outdoors. Moisture reaches the lock or connections and causes unreliable operation.
- Confusing lock monitoring with door-position monitoring. The controller receives less information than the specification requires.
- Leaving release and fire integration until the end. The locking device is selected without a complete, compliant route to unlock the door.
A practical pre-order checklist
- Is the door internal or exposed to weather?
- Is it a single leaf or a pair of doors?
- Which way does it open, and where is the secure side?
- What are the door, frame and header made from?
- Is there enough flat mounting space for the lock and armature?
- What holding force is appropriate for the opening and specification?
- Does the system need lock status, door status or both?
- Which model-specific bracket and fixing kit are required?
- What is the total current draw at the chosen voltage?
- How will normal exit, emergency release and fire-alarm release operate?
Choose the complete maglock system
The right maglock is the one that suits the door, fits properly, provides the required feedback and works as part of a complete release strategy. Holding force matters, but alignment, brackets, power and control are what make the installation dependable day after day.
Door Access Supplies stocks internal, external, single, double, monitored and MDS maglocks, together with matching brackets, armature housings, plates and fixing accessories. For the wider system, visit the Access Control Parts page or contact the team before ordering if you need help matching a lock to its bracket and power supply.
