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NodOn SEM-4-3-20

3CT Energy Meter. Works with Zigbee2MQTT with no vendor hub or cloud: it pairs with a Zigbee stick and shows up in Home Assistant.

Vendor
NodOn
Model
SEM-4-3-20
Type
Other devices
Power
mains: usually a router that extends the mesh
Firmware updates (OTA)
yes, through Zigbee2MQTT

Find it in shops: AliExpress

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What it exposes

FeaturePropertyValuesControl
Energy resetenergy_resetresetsettable
Power factorpower_factor—read only
Power factor - Phase Bpower_factor_phase_b—read only
Power factor - Phase Cpower_factor_phase_c—read only
Reactive power - Phase Apower_reactiveVARread only
Reactive power - Phase Bpower_reactive_phase_bVARread only
Reactive power - Phase Cpower_reactive_phase_cVARread only
Apparent power - Phase Apower_apparentVAread only
Apparent power - Phase Bpower_apparent_phase_bVAread only
Apparent power - Phase Cpower_apparent_phase_cVAread only
Total active powertotal_active_powerWread only
Total reactive powertotal_reactive_powerVARread only
Total apparent powertotal_apparent_powerVAread only
Consumed energy - Phase Aenergy_tier_1kWhread only
Produced energy - Phase Aproduced_energy_tier_1kWhread only
Consumed energy - Phase Benergy_tier_2kWhread only
Produced energy - Phase Bproduced_energy_tier_2kWhread only
Consumed energy - Phase Cenergy_tier_3kWhread only
Produced energy - Phase Cproduced_energy_tier_3kWhread only
Identifyidentifyidentifysettable
PowerpowerWread only
VoltagevoltageVread only
AC frequencyac_frequencyHzread only
CurrentcurrentAread only
EnergyenergykWhread only
Total produced energyproduced_energykWhread only
Active power - Phase Bpower_phase_bWread only
Active power - Phase Cpower_phase_cWread only
Voltage - Phase Bvoltage_phase_bVread only
Voltage - Phase Cvoltage_phase_cVread only
Current - Phase Bcurrent_phase_bAread only
Current - Phase Ccurrent_phase_cAread only

MQTT: state and commands

Zigbee2MQTT publishes the device state to zigbee2mqtt/my_device (my_device is the name you give the device). An example message:

{
  "energy_reset": "reset",
  "power_factor": 0,
  "power_factor_phase_b": 0,
  "power_factor_phase_c": 0,
  "power_reactive": 0,
  "power_reactive_phase_b": 0,
  "power_reactive_phase_c": 0,
  "power_apparent": 0,
  "power_apparent_phase_b": 0,
  "power_apparent_phase_c": 0,
  "total_active_power": 0,
  "total_reactive_power": 0,
  "total_apparent_power": 0,
  "energy_tier_1": 0,
  "linkquality": 120
}

The device only reports data and takes no commands.

Watch the topics live from the browser: MQTT client.

How to pair it

  1. In Zigbee2MQTT click Permit join.
  2. Put the device in pairing mode: usually a long press of the reset button (5–10 s) until the LED blinks; bulbs: switch the power off and on 5–6 times.
  3. Keep the device close to the coordinator or a router while pairing.
  4. Give it a clear name: MQTT topics and Home Assistant entities are built from it.

Exact procedure and model notes: the device page in the Zigbee2MQTT docs. No coordinator yet: coordinator picker.

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