Sonoff SPM-4Relay 20A Wifi Smart Switch

Expand your smart energy management system with the Sonoff SPM-4Relay 20A Smart Switch. Designed as an essential extension unit for the Sonoff Stackable Power Meter (SPM) architecture, this module delivers robust multi-channel switching capability tailored for heavy-duty appliances, multi-tenant properties, and commercial facilities.

Important Note: The Sonoff SPM-4Relay requires a Sonoff SPM-Main controller to function. The Main Unit must be connected to at least one 4-Relay module to enable network connectivity and full smart functionality.

Key Features

• High Power Capacity: Supports up to 20A per channel across all 4 independent gangs, allowing reliable automation for high-wattage machinery, heaters, and HVAC equipment.
• Robust RS-485 Bus Communication: Interconnects with the SPM-Main unit via an industrial RS-485 interface, ensuring fast, stable, and interference-free data transmission over extended distances.
• Built-in Overload Protection: Protects your electrical system and downstream appliances by automatically cutting off power when predefined thresholds are exceeded.
• Stackable & Scalable Design: Combine multiple SPM-4Relay units with a single SPM-Main to easily monitor and control dozens of distinct electrical circuits on standard DIN rails.