Shelly Pro EM-50

Description

The Shelly Pro EM-50 is a professional-grade, DIN-rail mountable energy meter designed for precision monitoring and control within an electrical panel.

While most Shelly devices are “relays first” (they focus on switching power), the Pro EM-50 is a “meter first” device. It uses Current Transformers (CT clamps) to measure electricity without the current actually passing through the device itself, making it much safer for monitoring high-load circuits.

Professional Build: DIN-Rail & LAN

The “Pro” designation means it is built for the reliability required in commercial or high-end residential installations:

• DIN-Rail Mounting: It snaps directly into your breaker box alongside your circuit breakers.
• Ethernet (LAN) Port: In addition to Wi-Fi and Bluetooth, it has a hardwired Ethernet connection. This is vital if your electrical panel is a metal box that blocks Wi-Fi signals.

Key Features: The “EM-50” Label

• Two-Channel Monitoring: It comes with two 50A Current Transformers. You can monitor two separate single-phase circuits independently (e.g., your Main Grid intake and your Solar Inverter, or a Heat Pump and an EV Charger).
• High Accuracy: It features Class B accuracy (1%), making it precise enough for detailed energy audits or identifying “power vampires” in your home.
• Contactor Control (Built-in Relay): It includes an integrated 2A dry contact relay. This is not meant to power a heavy load directly; instead, it’s designed to trigger a “contactor” (a heavy-duty industrial switch) to turn a whole circuit on or off based on your energy data.

Technical Specifications

Best Use Cases

The Pro EM-50 is the “brain” for energy management. It’s perfect for:

• Solar/PV Systems: Monitor how much energy you are exporting to the grid vs. how much you are importing in real-time.
• Load Shedding/Peak Shaving: Use scripting to automatically turn off your pool pump or water heater if your total house consumption exceeds a certain limit.
• Preventative Maintenance: Monitor for abnormal power draw in HVAC systems or refrigerators, which can signal a motor is about to fail.
• Small Businesses: Track energy usage across different departments or high-power machinery for cost allocation.

Summary: Pro EM-50 vs. Pro 3EM

• Shelly Pro EM-50: Best for single-phase homes or monitoring two specific large appliances. It uses 50A clamps.
• Shelly Pro 3EM: Best for three-phase industrial power or monitoring the entire intake of a massive luxury home. It uses 120A or 400A clamps.

Note: Whilst the Shelly configuration is mostly DIY, any electrical work must be done by a registered electrical contractor and we recommend Straton Electrical.