Shelly EM Gen3 + 50A CT
Clamps on without rewiring · Electrician install
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Which appliance is driving the power bill?
Clamp the Shelly EM Gen3 CT around the circuit for the hot water, air con or pool pump and see its draw and daily kWh in the app. No rewiring of the load. Diagram: Shelly.
Want to monitor a load and switch it off if it misbehaves?
The Shelly EM Gen3 CT watches the load and its contact drives a relay or contactor, so a pump that runs dry or a heater left on can be cut automatically. Diagram: Shelly.
Small inverter or micro-inverter: want to see what it is actually producing?
Feed the inverter output through the Shelly EM Gen3 and the meter shows generation live in the app, with history by hour and day. A cheap way to prove a small solar setup is pulling its weight. Diagram: Shelly.
Key features
50 A clamp included: ready to install without sourcing a separate CT.
2 CT channels: monitor 2 circuits, such as solar and mains, from 1 unit.
Contactless metering: clamps on; no need to break the circuit to measure it.
Local data logging: 10+ days stored on-device at 1-minute resolution, no cloud required.
No hub needed: connects straight to Wi-Fi with its own local web interface.
Matter upgradable: not certified today; Shelly lists it as a future firmware capability.
Know the clamp limit: supports CTs up to 50 A; the 120 A clamp is not compatible with this model.
Works with
Home Assistant
Shelly Smart Control app
MQTT
About this product
The Shelly EM Gen3 clips onto the mains via contactless current transformers rather than sitting in-line, so it measures what a circuit draws without breaking the circuit itself. This 50A-clamp version comes with the clamp in the box and covers 2 CT channels, useful for keeping tabs on 2 separate loads, a solar circuit and a general board tail, say: from 1 unit.
It's a metering device first: active and apparent power, energy, power factor and reactive energy, plus a small dry-contact relay output (240 V~/2 A) if you need to drive a contactor rather than switch a full load directly. Data is stored locally for at least 10 days at 1-minute resolution, stretching to a full year if you connect it to the Shelly cloud.
Gen3 brings Shelly's own chip with 8 MB of memory and Shelly's "virtual components" feature for folding third-party devices into the same app view. Shelly says it is designed to be upgradable to Matter, but it is not Matter certified today.
Model: S3EM-002CXCEU
Mains-side CT clamp install at the switchboard: licensed electrician required; clamps are contactless but still involve opening the board.
Tech specs
Physical
| Model | S3EM-002CXCEU |
| Dimensions | 37 × 42 × 16 mm (EM unit); 50A clamp separate |
| Weight | 23 g |
Electrical
| Max load | 0 to 80 A ammeter range (50A clamp included, 80A clamp optional); W not stated |
| Power monitoring | Yes |
| Operating temperature | −20 to 40 °C |
Connectivity
| Wi-Fi | 802.11 b/g/n |
| Bluetooth | 4.2 |
Compatibility
| Compatibility notes | Matter shown by Shelly as a future upgrade path only. Not certified today. |
In the box
| What's in the box | 1 × 50A CT clamp |
Warranty
| Manufacturer warranty | 3 Years |
| Free Ohmly extension | +1 Year Free Ohmly Warranty |
