SONOFF SPM Smart Stackable Power Meter
A scalable power-monitoring and switching system made from a main communication unit and one or more four-relay modules.
Key features
- One Main Unit supports multiple SPM-4Relay modules
- Four isolated channels per relay module
- Up to 20A per channel within system limits
- Energy data, operation logs and overload protection
- MicroSD-based local history storage on the main system
Installation and compatibility
The Main Unit and at least one 4-Relay module are required for an operating system. Plan panel space, network topology and protective devices before installation.
A 2.4 GHz Wi-Fi network is required. App and third-party integration availability depends on the selected ecosystem.
Safety notice: Electrical ratings, wiring method and load type must be checked before installation. Mains-powered devices should be installed by a qualified electrician.
Manufacturer reference: https://sonoff.tech/products/sonoff-smart-stackable-power-meter





