What's the difference between Shelly's EM and PM devices?
While Shelly have both EM and PM devices designed to monitor energy consumption for connected devices, there are a few key differences between the two!
The EM stands for energy monitoring; this device is designed to only measure how much energy a device uses (or how much energy is produced by renewable sources like wind turbines or solar panels.)
This device doesn't actually handle the electrical load however, so it can't control external contactors or devices. To turn devices on and off with a Shelly EM, you'll need an add-on like the Shelly Pro 3EM Add-On
Unlike the Shelly EM, the Shelly PM can both monitor the power usage of individual devices or circuits, and provide control features - ie, turning devices on and off. This is because the Shelly PM actually handles the load itself.
| Feature |
|
|
| Max Current | Up to 120A per phase (via CT clamps) | Up to 16A (depends on model) |
| Control Ability | Monitoring only | Monitoring + On/Off control |
| Applications | Whole-home/industrial energy monitoring | Individual appliances or small circuits |
| Voltage Range | Supports three-phase installations | Primarily single-phase devices |
| Use Case | High-power systems and solar setups | Home automation and appliance management |
