Relays are often the small components that make different parts of an access control or automatic door system work together. They allow one device to trigger, switch or control another circuit, helping installers connect locking equipment, exit buttons, door controllers, fire alarm interfaces and other low-voltage equipment.

Our collection includes multipurpose switching relays, adjustable timer relays, fire switching modules, fused output boards, voltage reducers and a two-door interlock controller. These products can be used within compatible access control systems, door entry installations, security systems and automatic door applications.

What Does an Access Control Relay Do?

An electrical relay uses an input or trigger signal to operate a separate set of switching contacts. This allows a low-current signal from a keypad, reader, exit button or controller to switch another circuit.

Depending on the relay and system design, it may be used to:

• Switch a magnetic lock or electric strike

• Interface a door controller with other equipment

• Add a timed delay to a door-release circuit

• Provide normally open or normally closed switching

• Operate equipment from a low-current trigger

• Interface access control equipment with a fire alarm

• Distribute power across several protected outputs

• Control automatic-door activation or release signals

• Coordinate two doors within an interlock arrangement

The correct relay depends on the supply voltage, trigger type, contact arrangement and electrical load being switched.

Multipurpose Access Control Relays

Multipurpose relays are useful where a straightforward switching interface is required between two parts of a system.

The RL01 12V multipurpose relay is a compact low-current switching module with dual changeover contacts. It can be used within compatible access control, door entry and security systems where a 12V trigger needs to operate another circuit.

For installations requiring greater input flexibility, the RL02 12/24V multipurpose relay accepts compatible AC and DC trigger voltages and provides dual changeover relay outputs. It can be used where a low-current control signal needs to switch a separate device or higher-current load within its rated capacity.

Typical applications may include:

• Maglock and electric-strike switching

• Door-release circuits

• Keypad and proximity-reader outputs

• Exit-button interfaces

• Door controller outputs

• Alarm and indication circuits

• Automatic-door activation signals

• Compatible lighting or sounder control

Always confirm the relay contact rating against the connected load. The coil or input voltage must also match the control signal being used.

Timer Relays for Door Release

Timer relays introduce a controlled delay or timed output into an electrical circuit. In access control installations, this can be useful where a door lock must remain released for a set period following an authorised input.

The EASY-RELAY 12V timer module provides an adjustable delay of up to 15 seconds. It includes dedicated button-input and lock-output connections for compatible door-release applications.

For installations requiring a wider range of timing and trigger options, the RL03 12/24V LED timer relay supports 12VDC and 24VDC systems, positive or negative triggering and normally open, common and normally closed relay contacts. Its LED indication also assists with adjustment and fault finding.

Timer relays may be used with compatible:

• Push-to-exit buttons

• Keypads and fob readers

• Electric locks and strikes

• Automatic-door operators

• Door entry controllers

• Alarm and indication equipment

The selected timing arrangement should suit the door, locking device and expected user movement. Excessively short release times can make a door difficult to use, while unnecessarily long times may affect the intended security of the entrance.

Fire Relays and Emergency Door Release Interfaces

Access-controlled doors may need to respond to a fire alarm or other emergency signal. Fire interfaces must be selected and wired according to the locking equipment, fire strategy and required release method.

The FRM-100 12/24V fire relay provides a switching interface for compatible fire alarm, access control and door-release circuits.

Where several circuits need to be controlled, the FFOB-4 fire fused output board combines fire switching with four individually fused outputs. It can be used to switch or disconnect multiple compatible devices following a fire alarm signal while retaining individual circuit protection.

Related products can be found in our Fire and Alarm Activation collection.

Fire alarm and door-release arrangements are safety-critical. A relay should not be added solely because a magnetic lock or controlled door is present. The required operation must be established from the fire strategy, means-of-escape design and relevant system requirements. Installation and commissioning should be completed by suitably competent professionals.

Fused Power Distribution Boards

A fused distribution board allows a single compatible power source to supply several separate circuits. Individual fuses help prevent a fault on one output from directly affecting every connected device and make circuit identification and fault finding more straightforward.

The RLO4 four-way fused distribution board divides one suitable low-voltage supply across four individually fused outputs with LED status indication.

For systems containing more connected devices, the RL08 eight-way fused output board provides eight separately fused outputs and status indication.

These boards may be useful when supplying multiple compatible:

• Maglocks or electric strikes

• Keypads and proximity readers

• Door controllers

• Relays and interface modules

• Exit buttons and indication equipment

• Security-system accessories

The total current demand of every connected device must remain within the capability of the access control power supply. Cable length, voltage drop, fuse ratings and the current drawn by continuously powered locking equipment must also be considered.

Voltage Reduction Modules

Some installations contain equipment that operates at different DC voltages. A voltage reduction module allows a lower-voltage device to be powered from a suitable higher-voltage supply without adding a completely separate PSU.

The VRM24-12 voltage reducer converts a 24VDC input to a 12VDC output with a maximum stated output current of 1A.

The VRM2 adjustable voltage reduction module accepts a wider DC input range and provides selectable lower output voltages through its onboard configuration.

Before fitting a voltage reducer, check:

• The input voltage available

• The output voltage required

• The maximum current drawn by the connected equipment

• The polarity of the DC supply

• Whether the module requires an enclosure

• The voltage drop and cable length

• The manufacturer’s requirements for the connected device

A voltage reducer must not be overloaded or used to supply equipment outside its stated ratings.

Two-Door Interlock Controllers

An interlock system coordinates two controlled doors so that both cannot normally be opened at the same time. These arrangements may be used where access between two areas needs to be more tightly controlled.

The DLIM two-door interlock controller provides separate inputs, outputs and monitoring connections for two access-controlled doors. It can be used within a correctly designed airlock or door-interlock arrangement.

Door interlocks require careful system design. Lock operation, door monitoring, emergency release, fire alarm response and user safety must all be considered before installation.

Choosing the Correct Relay or Interface Module

Before ordering an access control relay, timer or voltage module, confirm:

• The available supply and trigger voltage

• Whether the signal is AC or DC

• Positive or negative trigger requirements

• Normally open, normally closed or changeover contacts

• The current and voltage of the load being switched

• The number of circuits or outputs required

• Whether a timer function is needed

• Whether fire alarm switching is involved

• The required fuse protection

• The space and enclosure available for installation

• The correct fail-safe or fail-secure system behaviour

Never select a relay from its supply voltage alone. The input requirements, contact arrangement and switching capacity must all suit the intended circuit.

Complete Your Door Control System

Browse our complete range of Access Control Parts and Automatic Door Parts, including:

• Access control power supply units

• Maglocks and electromagnetic door locks

• Electric strikes

• Push-to-exit buttons and door-release switches

• Emergency break glass call points

• Automatic door switches and keyswitches

• Lockable boxes and protective covers

Relay and control circuits should be designed, wired and tested by somebody with the necessary knowledge of the connected door, lock and control equipment.