Power Supply Units (PSU) | Door Access Supplies

PSUs

Our access control power supply collection includes 12V and 24V PSUs for electronic locking, door entry, security, fire-door retention and low-voltage control systems. The range covers compact plug-in power supplies, enclosed battery-backed units, monitored PSUs, DIN-rail modules and multi-output power supplies for larger installations.

Available outputs range from compact 0.5A supplies through to higher-capacity 10A units. Options include 12VDC, 13.8VDC, 24VDC, 27.6VDC and 24VAC models, so it is important to match the supply voltage, current rating and operating type to the connected equipment.

Power Supplies for Access Control Systems

An access control power supply converts the incoming mains supply into the low-voltage output required by locks, controllers, readers, keypads and other system components.

The PSU must be capable of supporting the total electrical load of every connected device. This may include:

Access control panels and door controllers
Keypads and proximity readers
Magnetic locks
Electric strikes and solenoid bolts
Emergency door-release equipment
Door-entry devices
Relays and interface modules
Audible or visual indicators
Battery-charging requirements

Each device’s maximum current consumption should be included in the calculation. Where a system contains several locks or doors, the maximum simultaneous load must be considered rather than looking at each item individually.

Our full selection of compatible system components can be found in the Access Control Parts range.

Choosing Between 12V and 24V Power Supplies

The PSU output voltage must match the equipment being powered. A device marked only for 12VDC should not be connected to a 24VDC supply, and a 24VAC output should not be treated as interchangeable with 24VDC.

Twelve-volt power supplies are widely used for access controllers, keypads, readers, CCTV equipment and compatible electronic locks. Examples include:

CP1210/SM 12VDC 1A Power Supply – a compact plug-in supply for compatible low-current equipment.
CP1230/SM 12VDC 3A Power Supply – provides additional capacity for systems with a higher combined load.
CP1250/SM 12VDC 5A Power Supply – a higher-output encapsulated supply for compatible installations where battery backup is not required.

For equipment requiring 24VDC, the CP2425/SM 24VDC 2.5A Power Supply provides a compact encapsulated switch-mode option without battery backup.

The collection also includes the CP2405 24VAC 0.5A Power Supply for compatible equipment specifically requiring an AC supply. Always check whether the connected device needs AC or DC before ordering.

Understanding 13.8VDC and 27.6VDC PSUs

Battery-backed supplies for nominal 12V systems commonly provide a regulated output around 13.8VDC. This allows compatible 12V equipment to be powered while the PSU maintains and charges an attached 12V standby battery.

In the same way, 27.6VDC power supplies are used with compatible nominal 24V systems and can support an appropriate 24V standby-battery arrangement.

The equipment manufacturer’s voltage tolerance must still be checked. A product being described as suitable for a nominal 12V or 24V system does not mean that every device will accept every charging voltage.

Battery-Backed Access Control PSUs

A battery-backed PSU can maintain compatible access control or security equipment during a mains-power interruption. The actual operating time will depend on:

The total connected load
The capacity and condition of the battery
The battery-charging circuit
Cable losses
Ambient temperature
The system’s low-voltage cut-off
How frequently locks and other devices operate

The collection includes enclosed 13.8VDC PSUs in different current ratings and housing sizes. For example, the 1201SM-2 13.8VDC 1A Power Supply is housed in a hinged steel enclosure and can accommodate a compatible 12V standby battery up to the capacity stated on its product page.

For higher-load nominal 24V systems, the new-generation range includes:

These enclosed supplies incorporate battery-charging capability and protection features. The permitted battery arrangement and maximum battery capacity should be checked on the individual product page before installation.

Compatible replacement batteries are available from our 12V Sealed Lead Acid Battery collection.

Calculating the Required PSU Current

The current rating of a PSU is shown in amperes or amps. To select the correct unit, add together the maximum current consumption of all connected equipment.

For example, a system could include a controller, reader, keypad, maglock, break-glass unit and relay. Each item contributes to the total current required from the power supply.

The PSU should not be selected solely because its rating is slightly higher than the normal operating load. Allowance may also be required for:

Lock activation or inrush current
Battery charging
Additional interfaces and indicators
Future equipment additions
Manufacturer-required operating margins

Some PSU ratings represent the unit’s total available capacity rather than the full current available to the connected load after battery charging. Always check the product specification instead of assuming that the complete advertised rating can be assigned to external equipment.

Power Supplies for Maglocks and Electronic Locking

Electromagnetic locks require continuous power while locked, so their current consumption can form a significant part of the total system load. Double maglocks and multi-door installations can increase this requirement further.

When powering Maglocks, check:

Whether the lock is operating at 12VDC or 24VDC
Its current consumption at the selected voltage
How many locks will be powered
Whether the system requires battery backup
How emergency release will be achieved
Whether fire-alarm integration is required
The voltage drop across the cable run

Our Break Glass Call Points provide emergency door-release options for compatible access control systems. Final circuit operation must follow the approved design and requirements for the doorway.

Multi-Output and Fused Power Supplies

A multi-output PSU allows several devices to be supplied from one central enclosure. Individually fused outputs can make fault identification and circuit isolation more straightforward because a fault on one output does not necessarily remove power from every connected device.

The CP12-5 12VDC 5A Power Supply provides five individually fused outputs, while the CP12-10 12VDC 10A Power Supply provides ten fused outputs for larger compatible systems.

The stated 5A or 10A capacity is the total PSU rating and is not available independently on every output. The combined load across all outputs must remain within the unit’s limits, and the permitted current for each individual circuit must also be observed.

These supplies can be useful for centralised access control, CCTV, door-entry and security installations requiring several separately protected circuits.

Fire-Door Retention Power Supplies

Fire-door hold-open magnets and other retention equipment can require a purpose-designed power supply that responds to an external fire-alarm signal.

The A-2401/4TRS 24VDC 1A Four-Way Power Supply provides four distributed outputs for compatible fire-door retention devices. For installations requiring additional capacity, the 2402/4TRS 24VDC 2A Four-Way Power Supply provides four individually fused outputs.

These models support external voltage or voltage-free triggering and are intended for compatible hold-open magnets, door retainers and related fire-door equipment. They do not support battery backup.

Browse our Magnetic Hold-Open Devices and Fire Alarm Components for associated retention and interface equipment.

Monitored Power Supply Units

A monitored PSU provides outputs that allow another system to identify specified power-supply faults.

The 2402SM-2MP 27.6VDC 2A Monitored Power Supply includes voltage-free monitoring outputs for mains, battery and PSU status. It is housed in a hinged steel enclosure and is designed for compatible installations requiring battery backup and remote fault reporting.

A monitored PSU does not automatically communicate with every alarm or building-management system. The receiving equipment must accept the available contact type, and the fault outputs must be wired and programmed correctly.

DIN-Rail and Module-Only Power Supplies

Module-only PSUs are suitable where a correctly designed enclosure or control cabinet is already available. They give panel builders and system manufacturers greater flexibility than a complete boxed power supply.

The collection includes 13.8VDC and 27.6VDC module-only options in several output ratings. The 12TENSM 13.8VDC 10A Module provides a higher-capacity DIN-rail-mounted option for compatible control panels and electrical enclosures.

A bare PSU module must only be installed inside a suitable enclosure with the necessary mains isolation, earthing, circuit protection, cable restraint and access protection.

Intelligent and Security-Grade Power Supplies

The SMART-G3 Digital Display Power Supply is intended for compatible security and access control installations requiring status indication, battery support and additional monitoring features.

Its integrated display provides local system information, while the steel enclosure can accommodate a compatible standby battery. Check the individual product specification and required security grade before selecting it for a particular installation.

Selecting the Correct Access Control PSU

Before ordering a power supply, confirm:

Required output voltage
AC or DC operation
Maximum total current load
Current required for battery charging
Number of powered devices
Number of separately fused outputs
Battery-backup requirements
Required standby duration
Battery size and enclosure capacity
Monitoring or fault-output requirements
Fire-alarm interface requirements
Internal or external installation conditions
Cable length and expected voltage drop
Required protective devices and isolation

Mains-powered equipment must be installed and tested by a competent person. Follow the PSU manufacturer’s instructions and the requirements of the connected door, security or fire system.

Shop Access Control Power Supplies Online

Door Access Supplies stocks 12V and 24V power supplies for access control, electronic locking, door entry, CCTV, fire-door retention and security installations. Choose from compact plug-in adaptors, battery-backed steel enclosures, monitored PSUs, DIN-rail modules and multi-output fused power supplies.

Browse the collection above or explore our related ranges of Access Control Parts, Relays, Lead Acid Batteries and Automatic Door Parts.