Sonoff MINI ONE PM-ZB1GSP – Zigbee Switch with Energy Metering

A Zigbee relay that knows how much energy your appliance uses

Sonoff MINI ONE PM-ZB1GSP is a flush-mounted Zigbee switch with energy metering that hides behind your existing wall switch or socket and controls a connected appliance or light up to 16 A. It is more than a plain relay – the device continuously measures voltage, current, instant power and consumed energy, so you can control the circuit and see what it really costs you, all in one place.

It is the fifth generation of the popular MINI Extreme range and, compared with ordinary “dumb” switches, it adds exactly what retrofit solutions usually lack – real consumption data without buying a separate energy meter or rewiring the whole installation.

Accurate metering of consumption and production, not just on/off

The built-in measuring circuit tracks voltage, current and instant power in real time, and the eWeLink app turns the data into clear daily, monthly and total consumption charts. You can export the data at any time and look back at which day or month the connected appliance cost you the most.

Metering is also bidirectional – the device distinguishes energy drawn from the grid from energy flowing the other way. That makes MINI-ZB1GSP useful where an ordinary one-way meter falls short: for example when tracking a small balcony solar system, where you want to see separately how much electricity you generate and how much you still draw from the grid.

On top of the measured data the app also builds an electricity bill – you set your own currency and unit price, or a time-of-use tariff with different rates at different hours of the day, and eWeLink keeps recalculating the real running cost of that circuit. That is how you find out whether it pays off to run the washing machine during the day or wait for the cheaper night rate.

Smart detection of the appliance status

The device does not track consumption just for statistics – it actively works with it. Based on power changes it can recognise the real operating state of the connected appliance (e.g. a coffee machine, oven or kettle up to 16 A) and send a notification to your phone when the job is done. An adjustable delay prevents the app from mistaking a short power drop – for instance while a washing machine fills or drains water – for the end of the cycle.

In the same way you can set up maintenance tracking: the app counts the time consumption stays above a defined threshold, and once the set interval adds up, it reminds you that service is due – ideal for pumps, boilers or other equipment with regular maintenance.

Multi-layer electrical protection

MINI-ZB1GSP continuously checks that voltage, current and power stay within safe limits. If the adjustable limits for overload, overcurrent, overvoltage and undervoltage are exceeded, it automatically disconnects the load – and the same logic protects the device itself from overheating. Overcharge protection is included too, extending the life of connected battery systems. You set all thresholds directly in the app according to the appliance connected to the relay.

Retrofit without tearing down walls

Compact dimensions of 39.5 × 33 × 16.8 mm let you fit the module directly into a standard wall box behind an existing switch or socket (the manufacturer recommends a box at least 60 mm deep). The look of the switch on the wall does not change at all – the device works as an intermediary between the switch and the appliance.

The external switch input supports several modes so that it matches your original switch: pulse mode (each short press toggles the state), edge mode (the relay toggles on every change of the switch position) and follow mode (the relay copies the position of a classic two-way switch). Thanks to that you can retrofit even where an ordinary two-way switch or push button is wired.

Especially useful is the Detached Relay mode – it separates the physical wall switch from the relay itself. Switching off at the wall no longer cuts the power, it only sends a press event to the system that you can use in automations. A smart bulb connected behind MINI-ZB1GSP therefore never loses power and stays controllable from the app, by voice or by scene, exactly like the other Sonoff smart switches in our range.

A stronger and more reliable Zigbee network

MINI-ZB1GSP communicates over Zigbee 3.0 (IEEE 802.15.4) and, because it is permanently mains-powered, it also works as a Zigbee router – it receives and forwards the signal of other battery-powered devices (sensors, buttons), extending the range and stability of the whole home network. The usual range to the Zigbee gateway is 180 m, or up to 250 m with Turbo Mode (higher transmit power) enabled.

If you cannot reach the Zigbee gateway or its signal is unstable, the eWeLink app can connect directly over Bluetooth Proximity Mode – the phone pairs with the device nearby and allows basic control and settings even without a gateway.

Fitting into the wider smart home ecosystem

Through a compatible Sonoff Zigbee gateway (e.g. ZBBridge-P, ZBBridge-U, NSPanel Pro or iHost) MINI-ZB1GSP joins the eWeLink app, which adds scheduling, voice control, smart scenes and device sharing with other users on top of control and energy metering. Through a Matter Bridge (ZBBridge-U, iHost or eWeLink CUBE) it can also be exposed in Apple Home, and through ecosystem Zigbee gateways directly in Amazon Alexa or Samsung SmartThings.

Advanced users will also appreciate direct Home Assistant support via ZHA or Zigbee2MQTT – relay state, measured energy, power and various diagnostic and protection states are all exposed, so you can fully use the device in local automations without relying on the cloud. Thanks to Zigbee binding you can even link MINI-ZB1GSP directly to a compatible Zigbee button (e.g. SNZB-01M) without the Home Assistant hub being involved on every press. If you are planning this integration, read our guide to integrating Sonoff devices with Home Assistant.

Who MINI ONE PM-ZB1GSP is for

• Households that want to control a light, heating or another appliance with a smart switch and at the same time see how much electricity it really uses.
• Owners of small balcony solar systems who want to track their own production and consumption in one place.
• Advanced Home Assistant users who want local energy metering via ZHA or Zigbee2MQTT without relying on the cloud.
• Households with mixed Zigbee devices from different brands, where MINI-ZB1GSP also comes in handy as a Zigbee router extending the range of the network.
• Tenants and owners who want a retrofit solution that leaves the look of existing switches and sockets untouched.

Use cases

• Retrofit without demolition – it replaces a classic switch right inside the wall box and keeps working with the original physical switch thanks to the optional pulse/edge/follow modes.
• Tracking the consumption of a specific appliance – a water heater, washing machine or air conditioner, for example, with hourly, daily and monthly history and the option to export the data.
• Cycle completion alerts – the app sends a notification when the consumption of a washing machine or dryer drops below a set threshold, with a delay that prevents false alarms while water is filling.
• A smart light that never goes offline – Detached Relay mode separates the physical switch from the relay, so switching off at the wall does not cut power to the smart bulb.
• Metering a balcony solar plant – thanks to bidirectional metering you see grid consumption and your own production separately in the app.
• Zigbee with no gateway nearby – Proximity Mode lets you connect to the device straight from your phone over Bluetooth when the Zigbee gateway is out of reach.
• Maintenance planning – the system adds up the running time above a set power threshold (e.g. a pump or a boiler) and reminds you about service exactly when it is needed.

Key features and protocols

Why choose MINI ONE PM-ZB1GSP

• Switching and energy metering in one compact module – no need to buy a separate energy meter.
• Bidirectional metering lets you track balcony solar production as well as consumption.
• It also works as a Zigbee router, so alongside its own job it strengthens the whole home network.
• Open Home Assistant support (ZHA/Zigbee2MQTT) with no cloud dependency.

Compared with the Sonoff MINI-ZB1GP you additionally get a switching function – MINI-ZB1GP is a standalone energy meter without a relay, suitable only where you want to measure and not also control the connected load.

Frequently asked questions

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