Ajax SmartPlug and Relay: The UK Installer's Automation Guide

A good alarm should do more than make a noise: it should switch things on, switch things off and open or release equipment when something happens. This guide covers the Ajax SmartPlug (Ajax’s own name is the Socket (type G) Jeweller) and the Ajax Relay Jeweller — the two wireless devices that let an Ajax hub control lights, heaters, gates, door releases and other equipment. It is written for UK installers who want to add automation to an Ajax system, and for end users who want to know what a smart plug or relay can safely do. Every figure comes from Ajax Systems and is cited next to the claim.

Ajax SmartPlug and Relay automation guide for UK installers — Plug in, wire in, set a scenario — the Ajax SmartPlug and Relay turn alarm events into actions.

What this guide covers

The SmartPlug: a British-type (G) plug rated for up to 3 kW and 13 A, with energy monitoring and its own overload protection.
The Relay: a small dry-contact module powered from 7–24 V DC that switches up to 13 A at 230 V AC.
Scenarios: the triggers that fire them, and the limit of 5, 32, 64 or 100 scenarios depending on the hub.
Setup and limits: signal checks, pulse and bistable modes, and why an offline device misses its trigger.
Which to specify: a decision table and a short parts list.

What is the Ajax SmartPlug and what can it switch?

The Ajax SmartPlug is a wireless plug-in smart socket that sits between a UK wall socket and an appliance, switches the appliance on and off from the Ajax hub, and reports how much power it draws. Ajax lists the Socket (type G) Jeweller specification as 230 V~ at 50 Hz, a maximum continuous load of 13 A and up to 3 kW on a resistive load, with an average consumption of up to 1.5 W. Netview stocks it in white and black.

It is for indoor use only (IP20) and talks to the hub over Jeweller radio, with a range of up to 1,100 m in open space according to the Ajax user manual. Real buildings will give you far less, so always check the Jeweller signal level on site.

What does the SmartPlug protect against?

It has three independent protections: current, voltage and temperature. Ajax say the overcurrent limit is adjustable from 1 to 16 A in 1 A steps with a default of 13 A, and that values above 13 A are for short-term loads only. The plug also switches off if mains voltage falls outside 184–253 V AC. After a current-protection trip, power has to be restored from the app or the plug’s own button, so it will not quietly switch itself back on.

How does the SmartPlug energy monitoring work?

The Ajax app shows voltage, load current, power and energy consumed for whatever is plugged in. Values refresh every 36 seconds by default, power is displayed in 1 W steps, and the meter can be reset in the plug’s settings. That makes it useful for confirming that a heater, dehumidifier or pump has actually started, not only that it was told to.

What does the Ajax Relay do that the SmartPlug cannot?

The Ajax Relay switches fixed wiring and low-voltage circuits that a plug cannot reach — gate controllers, door releases, shutters, lighting circuits and similar equipment — through a potential-free (dry) contact. The Ajax Relay Jeweller is a 39 × 33 × 18 mm module with a flexible external antenna, designed to sit in a junction box, appliance enclosure or distribution board, and the Ajax Relay manual gives its key limits:

Supply: 7–24 V DC, with 12 V or 24 V DC recommended. The relay has no battery.
Resistive load: 5 A at 36 V DC, or 13 A at 230 V AC.
Inductive or capacitive load: 3 A at 24 V DC, or 8 A at 230 V AC.
Contact logic: normally open or normally closed, in bistable mode or in pulse mode of 0.5–255 seconds.
Output role: relay, blocking element or electric lock.
Range: up to 1,000 m in open space.

Ajax say a qualified electrician or installer should fit it, using 0.75–1.5 mm² cable, and that it should sit at least 1 m from routers and other sources of radio interference. Outdoors it must be enclosed in a sealed box to avoid condensation damage.

Should you specify the SmartPlug or the Relay?

Specify the SmartPlug when the load plugs into a standard UK socket and you want power monitoring, and specify the Relay when you need to switch a fixed circuit or a dry contact. The table sets out the differences using the Ajax figures above.

Feature	SmartPlug (Socket type G)	Relay Jeweller
Power source	230 V mains socket	7–24 V DC supply
Maximum resistive load	3 kW, 13 A	13 A at 230 V AC, 5 A at 36 V DC
Energy monitoring	Yes: voltage, current, power, energy	No
Modes	Bistable, or pulse 1–255 s	Bistable, or pulse 0.5–255 s
Typical job	Lamps, heaters, fans, pumps, kit that plugs in	Gate, shutter or door release, lighting circuit, dry-contact input
Installation	Plug in, indoors only	Wired by a qualified installer

What can trigger an Ajax automation scenario?

Almost any change on the Ajax system can trigger a scenario: an alarm, a change of security mode, a time of day, a button press or a temperature reading. The Ajax scenarios manual lists these trigger types:

By alarm: one or more detectors, or the panic button, such as a MotionProtect U or DoorProtect U.
By alarm confirmation: fires when an alarm is confirmed in a chosen zone.
By schedule: a set time and repeat days, using the time zone set in the hub.
By arming or disarming: a change of security mode, or Night mode.
By button press: a short or long press (over 3 seconds) of an Ajax Button.
By temperature: above or below a threshold, from devices that show temperature in the app.
By keypad: the KeyPad TouchScreen can run up to six keypad scenarios, and the KeyPad Outdoor one.

Ajax also note that only a PRO or admin user can create scenarios, so sort out the user roles at handover. A water leak or fire event can drive a scenario too; our LeaksProtect water leak guide shows the detector side, and the Ajax LeaksProtect is the detector to pair with a plug that cuts power to a pump or appliance.

How many automation scenarios can each Ajax hub run?

The limit depends on the hub: 5 scenarios on the original Hub (2G) and Hub (4G), 32 on Hub 2, and 64 on Hub 2 Plus. According to the same Ajax scenarios manual, Superior MegaHub allows 100. Each trigger device in a temperature scenario counts separately and disabled scenarios still use hub memory, so plan the scenario list before you commission.

Hub	Scenario limit
Hub (2G) / Hub (4G) Jeweller	5
Hub 2 (2G) and Hub 2 (4G)	32
Hub 2 Plus	64
Superior MegaHub	100

For help choosing between the two current hubs, see our Hub 2 vs Hub 2 Plus guide. A Hub 2 kit is a good starting point if the customer has no Ajax system yet.

How do you set up an Ajax SmartPlug or Relay?

Add the device to the hub in the Ajax PRO app, check the signal, set the mode and then build the scenario. Both devices follow the same pattern:

Add the SmartPlug or Relay to the hub by scanning its QR code, as you would any Jeweller device.
Choose a position with a Jeweller signal of 2–3 bars, which is Ajax’s own advice for both devices. Add a ReX 2 range extender if the signal is weaker; our signal strength guide explains how to read it.
Set the mode: bistable if a press should toggle the state, pulse if the output should switch for a fixed time and then reset.
Set the contact state (normally open or normally closed), and on the SmartPlug set an overcurrent value that suits the appliance.
Create the scenario with the trigger, the device and the action.
Test it: trigger the event, watch the load, and for a Relay run the Jeweller signal strength test and a functional test as Ajax advise.

Both devices can also be operated manually. Ajax list the app, scenarios, a function button on the device and the Button as control methods, and say the Relay’s function button works with a 2-second press. A SpaceControl keyfob is covered in our SpaceControl, Button and Tags guide.

What are the practical uses for UK installers?

The usual jobs are lighting, access, heating and wiring other equipment into an alarm event. The examples below are application ideas rather than Ajax claims, and each must be checked against the load limits above.

Lighting on alarm: a SmartPlug on a floodlight or lamp that switches on when a detector triggers.
Arming-linked lighting: a lamp that comes on at a set time with a schedule scenario, or when the system is disarmed.
Gate or door release: a Relay in pulse mode to give a short release pulse from a keypad or Button press.
Cutting power to an appliance: switching off a pump or heater when a LeaksProtect or temperature scenario fires.
Third-party equipment: where a dry contact is needed from an alarm event, a Relay does the job; where you need to bring a wired detector into Ajax, look at the Universal Transmitter or the MultiTransmitter described in our MultiTransmitter guide.
Deterrent systems: a Relay can start or stop equipment such as the fog generators covered in our security fog systems guide, subject to the maker’s wiring requirements.

What are the limits and safety points to explain to customers?

The main limits are that an offline device misses its trigger, that loads must stay within the stated ratings, and that fixed wiring must be done by a competent person. Ajax state clearly that a device that is offline when its trigger occurs will not run the scenario, and that includes after a power outage: a 10 a.m. schedule is missed if power fails at 9:55 and returns at 10:05. Do not use an Ajax plug or relay as the only control for anything where failure puts people at risk, and do not use a SmartPlug on a load above its rating.

Both devices work with one hub at a time and only with Ajax hubs and range extenders; Ajax say they are not supported by uartBridge or ocBridge Plus. For fixed installations in dwellings in England, Part P of the Building Regulations covers electrical safety, so use a competent person and check which work is notifiable.

What parts should you quote for an Ajax automation job?

Quote the hub, the controlled device, the trigger device and any range extender, then add a DC supply if the job uses a Relay. A typical small job is a Hub 2 or Hub 2 Plus, one or more SmartPlugs, a Relay and a keypad or Button for manual control. Add a HomeSiren U if the customer also wants an internal sounder, and use the FireProtect 2 or a MotionCam U where a scenario needs a fire or photo-verified trigger. Our wireless alarm system guide covers the wider design, and the maintenance guide covers service visits.

Ajax SmartPlug versus Relay Jeweller comparison for automation scenarios — SmartPlug for plug-in loads, Relay for wired circuits and dry contacts.

Four step Ajax automation scenario setup workflow for UK installers — Add, check signal, set the mode, build and test the scenario.

Frequently asked questions

What is the Ajax SmartPlug?

It is Ajax’s Socket (type G) Jeweller: a wireless British-type smart plug rated up to 13 A and 3 kW with energy monitoring, controlled from the Ajax app, scenarios or its own button.

What is the maximum load for the Ajax SmartPlug?

Up to 3 kW and 13 A on a resistive load. With inductive or capacitive loads the maximum switching current drops to 8 A, according to Ajax.

Can the Ajax Relay switch mains voltage?

Its dry contacts are rated to 13 A at 230 V AC for resistive loads and 8 A at 230 V AC for inductive or capacitive loads, but it must be installed by a qualified electrician or installer.

Does the Ajax Relay need a power supply?

Yes. It runs from 7–24 V DC, with 12 V or 24 V recommended, and has no battery.

Will an Ajax scenario run if the SmartPlug is offline?

No. Ajax say an offline device misses the trigger and does not catch up when it reconnects.

How many scenarios can a Hub 2 Plus run?

64, compared with 32 on a Hub 2 and 5 on the original Hub, according to the Ajax scenarios manual.

Related guides

Order Ajax SmartPlugs, Relays and hubs from Netview

Netview is an authorised UK Ajax stockist based in Leicester. The SmartPlug, Relay, Hub 2 range, ReX 2 extenders and the full Ajax detector and keypad range are held in stock for same-day dispatch, with trade pricing for installers. Plan a new system with the Ajax system builder, or browse the full range at netviewcctv.co.uk.

October 30, 2026 | View: 7 | By: netviewcctv.co.uk