Shelly EM Gen4

Two-channel energy meter

A single-phase meter with two clamp-on current transformer channels up to 120 A and a 2 A dry contact for a contactor coil. It reports power, voltage, current and imported and exported energy per channel over Zigbee.

Shelly EM Gen4
  • Zigbee

Two-channel energy meter

Compatibility

Compatible with EpiSensor Edge over Zigbee.

Pair it with the Zigbee radio on an EpiSensor Gateway. Edge reads it locally on the Gateway.

Edge reads 24 values from it, listed under Interface.

Connect it with

Specifications

The EM Gen4, order code S4EM-002CXCEU, measures two circuits on one phase with clamp-on current transformers, so the monitored cables are not broken into. A 50 A transformer comes in the box; 80 A and 120 A transformers are also compatible. The meter itself takes its supply and voltage reference from L and N at 110 to 240 V AC.12

Power
Mains. Powered from 110 to 240 V AC at 50 or 60 Hz on its L and N terminals, under 1 W.1
Order code
S4EM-002CXCEU1
Channels
Single phase, two current transformer channels (IA, IB)1
Current transformers
50 A included; 80 A and 120 A compatible1
Current range
0 to 120 A1
Current accuracy
±2 % from 1 to 50 A, ±5 % from 0 to 1 A1
Voltage range and accuracy
110 to 240 V AC, ±2 %1
No-load threshold
30 VA per phase1
Relay output
Dry contact, 2 A at 240 V AC maximum1
External protection
2 A breaker, B or C characteristic, 6 kA, energy limiting class 31
Terminals
0.5 to 4 mm², 6 to 7 mm stripped, 0.4 Nm maximum1
Operating temperature
-20 to 40 °C1
Humidity
30 to 70 % RH1
Dimensions (H × W × D)
37 × 42 × 16 mm1
Weight
26 g1
Zigbee radio
IEEE 802.15.4, 2405 to 2480 MHz, under 20 dBm, repeater1
Zigbee range
Up to 100 m indoors, 300 m outdoors, depending on the site1
Local data log
At least 30 days of 1 minute records on the device1

Where it is used

Interface

On the Zigbee network it joins as a router and extends the mesh for other devices.1

Readings and settings, with units and ranges where Shelly publishes them. readable, readable and writable, writable only.4

Download
ReadingUnitRange or valuesAccess
Measurements 12
Active power, endpoint 2Instantaneous active power W - Read only
Voltage, endpoint 2RMS voltage V - Read only
Current, endpoint 2RMS current A - Read only
Frequency, endpoint 2Mains frequency Hz - Read only
Imported energy, endpoint 2Energy consumed, cumulative kWh - Read only
Exported energy, endpoint 2Energy fed back towards the supply, cumulative kWh - Read only
Active power, endpoint 3Instantaneous active power W - Read only
Voltage, endpoint 3RMS voltage V - Read only
Current, endpoint 3RMS current A - Read only
Frequency, endpoint 3Mains frequency Hz - Read only
Imported energy, endpoint 3Energy consumed, cumulative kWh - Read only
Exported energy, endpoint 3Energy fed back towards the supply, cumulative kWh - Read only
Controls 2
Relay outputDry contact relay output on endpoint 1 - ONOFF Read and write
IdentifyStarts the device identify routine - identify Write only
Settings 7
Wi-Fi enabledTurns Wi-Fi on or off - Binary state Read and write
Wi-Fi networkSSID of the Wi-Fi network to join - - Read and write
Wi-Fi passwordPassword for that network; write only - - Write only
Static IPv4 addressUsed when DHCP is off - - Read and write
Network maskFor the static address - - Read and write
Default gatewayFor the static address - - Read and write
DNS serverFor the static address - - Read and write
Diagnostics 3
Wi-Fi statusCurrent Wi-Fi connection status - - Read only
IP addressIP address currently assigned on Wi-Fi - - Read only
DHCP enabledWhether DHCP assigns the Wi-Fi network settings - Binary state Read only

The Zigbee definition has three endpoints. Endpoint 1 is the relay (state_1). Endpoints 2 and 3 are the two current transformer channels, so each measurement appears twice with the suffix _2 or _3, for example power_2 and power_3.4

Energy is split into imported energy (energy) and exported energy (produced_energy), both in kWh, which suits a channel on a solar inverter feed. Apparent power and power factor are calculated on the device but are not in the Zigbee definition.14

The same definition carries the device's Wi-Fi settings and status. Firmware updates are not delivered over Zigbee, so update the device over Wi-Fi before you switch it to Zigbee.34

Setup

  1. Wire it with the circuit dead

    Connect L and N through a 2 A B or C breaker. Clamp each current transformer around the live conductor of its circuit and connect it to IA or IB. Wire the contactor coil circuit through the relay's I and O terminals if you use it.1

  2. Update the firmware first

    While it is still on Wi-Fi, update its firmware from the Shelly app or the web interface at 192.168.33.1 on its own access point.2

  3. Open pairing in Edge

    In Edge, open pairing on the Gateway's Zigbee network.

  4. Switch it to Zigbee

    Press the button 5 times quickly. The device switches from Wi-Fi (Matter) to Zigbee and stays in inclusion mode for 2 minutes.2

  5. Check both channels

    Load each circuit in turn and compare current with a clamp meter. If power reads negative on a consuming load, turn that transformer round.

Sources

  1. Shelly EM Gen4 knowledge base page (opens in a new tab) Shelly
  2. Shelly EM Gen4 user and safety guide (opens in a new tab) (PDF) Shelly
  3. Shelly S4EM-002CXCEU device documentation (opens in a new tab) Zigbee2MQTT
  4. Shelly S4EM-002CXCEU converter source (opens in a new tab) zigbee-herdsman-converters

Further reading

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