Frequently asked questions

• What is the maximum current the Shelly Pro 3EM-400A can measure?

  Each phase is measured through an external current transformer rated 0-400 A, so the model covers loads far larger than standard 50 or 120 A clamps.
• Does the Shelly Pro 3EM-400A have a relay to disconnect the load?

  No, this meter has no built-in relay and does not disconnect the load itself. To drive a contactor you add a separate Shelly Pro Add-on.
• What network connections does the device support?

  The Pro 3EM-400A connects via Wi-Fi 802.11 b/g/n, a wired Ethernet RJ45 port and Bluetooth 4.2, plus MQTT, HTTP and WebSocket for integrations.
• How long does the meter store measurement data locally?

  The device stores at least 60 days of measurements at 1-minute resolution locally, so data stays available even if the internet drops.
• Which electrical parameters does it measure per phase?

  It measures active and apparent power, active and apparent energy, fundamental energy, power factor, voltage and current at accuracy class B (±1%).
• Can I integrate the meter into Home Assistant?

  Yes, thanks to local MQTT, HTTP and WebSocket support the device integrates into Home Assistant and other energy-monitoring platforms.