Device overview
Shelly 1PM Mini Gen4 (model S4SW-001P8EU) combines an 8 A smart relay with single-channel power and energy measurement. It is designed for lights and smaller appliances where a compact module can be wired behind a wall switch, socket, or inside a suitable enclosure. It is not a whole-home meter and should not be selected for loads above its published 8 A switching limit.
Core features
- Direct measurement of the connected load's active power and consumed energy
- One normally open relay output rated up to 8 A at 240 V AC
- 110-240 V AC single-phase supply
- Wi-Fi 6, Zigbee, Bluetooth 5.0, and Matter connectivity
- Embedded web interface, schedules, webhooks, scripting, MQTT, Modbus, and WebSocket support
- Overtemperature, overvoltage, overcurrent, and overpower protection functions
Installation
The module is intended for an indoor wall box or another suitable electrical enclosure. It uses direct in-line L, N, O, and SW terminal wiring and does not use a current transformer. Installation must respect the 8 A device limit, conductor and protective-device requirements, enclosure space, local electrical rules, and the thermal conditions around the module. Mains wiring should be completed by a qualified person.
Measurement and comparison fit
This is an appliance- or circuit-level monitor rather than a whole-home energy meter. The direct measurement path is convenient when the target load is within 8 A and relay control is useful. It is a poor fit for high-current circuits, three-phase monitoring, main incomer measurement, or sites that require a certified billing-grade accuracy class. Shelly's current exact-model documentation does not publish a formal metering accuracy class, so buyers should not compare it as if it were a MID or revenue-grade meter.
Local control, cloud, and Home Assistant
The device can operate on a local Wi-Fi network through its embedded web interface and documented local interfaces, including HTTP/RPC, MQTT, Modbus, webhooks, and WebSockets. Shelly Cloud is optional and mainly adds remote app access and hosted history. Home Assistant's official Shelly integration supports all Shelly generations and communicates directly with the device, so a cloud connection is not required for normal local integration.
Solar and import/export limitations
Shelly describes the product as measuring the consumption of the connected load. The reviewed exact-model sources do not claim bidirectional import/export energy measurement or solar-export metering. For PV flow, grid import/export, or whole-home solar monitoring, use a purpose-built bidirectional meter or multi-channel CT product instead.
Best-fit use cases
- Monitoring and controlling lighting, fans, and small appliances
- Adding measured relay control where wall-box space is limited
- Local-first Home Assistant energy and automation projects
- Matter, Wi-Fi, or Zigbee retrofit projects that stay within the electrical rating
Advantages and limitations
The main strengths are compact size, direct local integrations, multiple radio choices, and combined control plus metering. The main limitations are the 8 A ceiling, single-channel/single-phase scope, no published formal accuracy class, and no verified bidirectional solar import/export measurement.
Buying and official sources
The Shelly Europe store listed the single unit at EUR 21.90 including VAT and in stock on 2026-09-09 CST; the two-pack was out of stock. Confirm destination availability, electrical compliance, shipping, and final checkout pricing. See the official Shelly product page, Knowledge Base, device API documentation, printed safety guide, and Home Assistant Shelly integration documentation for current setup details.