Shelly
EM Gen3 Energy Meter
A clamp-based energy meter small enough to sit in a wall box. Two clamps, so it can watch two circuits at once, with a 50 A clamp in the box and a dry contact relay for driving a contactor.
$99.95 inc GST In stock at supplier · dispatches in 2 business days
1
Free shipping over $150 Ordered in from our supplier. Allow about 2 business days before it dispatches.
30-day returns Unopened items in their original packaging
Everything you need to know
The sections below cover what this meter does, the jobs people put it on, the full specifications, and how warranty and returns work. If something's still unanswered, the questions at the bottom cover the common ones.
Product features
What this meter does
The EM Gen3 measures with current transformers: a split clamp that closes around a live conductor, so the circuit never passes through the meter itself. That's what lets a small in-wall module read a heavy circuit. It takes up to two clamps, so one unit can watch two circuits, and a 50 A clamp comes in the box. It also has a dry contact relay rated 2 A at 240 V. That isn't for switching a load directly, it's for driving a contactor that does.
Up to two CT clamps, two circuits from one meter
50 A clamp included, 80 A available separately
Reads to 80 A, ±2% accuracy
Dry contact relay for contactor control
Ten days of history on the device
The meter keeps at least ten days of readings at one-minute resolution in its own storage. You can pull that back later without a cloud account holding it for you, and a dropout doesn't leave a hole in the record.
At least 10 days at one-minute resolution
Stored on the device, not in a cloud account
Readable over the local API
Automations that don't need the internet
Schedules, timers and scenes run on the relay itself, not on a server overseas. Set lights for sunset, a towel rail for weekday mornings, or a fan to run down after the bathroom light goes off, and it all keeps working through an internet outage. There's no subscription, and the embedded web interface gives you full control from a browser on your own network.
Schedules and scripts run on the device
No cloud account required for local control
Keeps working when the internet doesn't
How Shelly works
A Shelly is a small module that makes wiring you already have controllable. It joins your Wi-Fi directly, holds its schedules and scenes on the device itself, and keeps running them if your internet drops. Nothing you set up depends on Shelly's servers being reachable.
The device
The brain is the device
Shelly does the thinking locally, not in a data centre. Schedules, scenes and logic are stored on the unit and run there, so the lights still come on at dusk when the internet is out.
The network
No hub, no bridge
There is nothing to buy before the first one works. Where a Philips Hue setup is built around a Bridge that every light talks through, a Shelly joins your router directly and answers your phone from there.
The control
The app is optional
Every Shelly serves its own web interface, so you can set it up and run it from a browser on your own network, with no account. The Shelly Smart Control app and Shelly Cloud are free and add remote access and voice control, but nothing needs them.
The generations
What Gen1 to Gen4 means
Shelly has run through four hardware generations, and the same product name can exist in more than one of them. Later generations are faster and carry more radios than the ones before, which is why the generation is part of the name. The specifications on each page tell you which one you are looking at.
Getting started
1
It goes behind what you already have Start here
Shelly retrofits. The module fits behind the switch, socket or appliance that is already there, so your switch plates and fittings stay as they are and the original switch keeps working for anyone who just wants to flick it. Anything wired into a mains circuit is a job for a licensed electrician.
2
Open by design Then run it your way
Shelly publishes its local API and does not put it behind a developer account. Devices answer HTTP and MQTT on your own network and can run small scripts on themselves. That is why Shelly is the default choice for people building on Home Assistant, which ships an official Shelly integration.
Start with one and add more whenever you like. There is no hub to outgrow, and each Shelly works on its own whether you ever add another or not.
Works with
Also works with
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Pairs with Amazon Alexa
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Pairs with Google Home
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Pairs with Home Assistant
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Pairs with SmartThings
Connects over
On your Wi-Fi
Joins your home network; control from the app, no hub or bridge needed.
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Wi-Fi
Set up over Bluetooth
Used once, to get it onto your Wi-Fi.
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Bluetooth
Works offline
Runs on your home network. Only remote access needs the internet.
Specifications & Installation
Setup · 2:21
How to install it
Shelly's own step-by-step install, from isolating the power to fitting the clamp and wiring the meter in.
Watch setup videoNo specifications match.
Power
- Power
- Hardwired
- Standby power
- 1.2 W
- Phases
- Single-phase
- Channels
- 2 channels
- Measured by
- CT clamp
- Max current per circuit
- 80 A Also available: Mini
- CT clamps included
- Yes
- Accuracy (±)
- 2 %
- On-device history
- 10 days
- Relay output
- Yes
- Relay rating
- 2 A
- Power supply
- 110 - 240 V~ 50/60 Hz
- External protection
- 2 A, tripping characteristic B or C, 6 kA interrupting rating, Energy limiting class 3
- Form
- In-wall
- Housing material
- Plastic
- Standard
- 802.11 b/g/n
- Range (indoors)
- 30 metres
- RF band
- 2412 - 2472 МHz
- Max. RF power
- < 20 dBm
- Version
- 4.2
- Range (indoors)
- 10 metres
- RF band
- 2402 - 2480 MHz
- Max. RF power
- < 4 dBm
- Operating temperature
- -20–40 °C
- Operating humidity
- 30–70 % RH
- Max altitude
- 2000 metres
- Size (HxWxD)
- 37x42x16 mm / 1.46x1.65x0.63 inch
- Weight
- * EM Gen3 - 23 g / 0.81 oz * CT 50A - 50 g / 1.76 oz
- Screw terminals max torque
- 0.4 Nm / 3.5 lbin
- Conductor cross section
- 0.5 to 4 mm² / 20 to 11 AWG (solid, stranded, and bootlace ferrules)
- Conductor stripped length
- 6 to 7 mm / 0.24 to 0.28 in
- Mounting
- Wall console, Electrical cabinet
- Shell color
- * White * Charcoal gray
- Connectors color
- Black
- Max. switching voltage
- 240 V~
- Max. switching current
- 2 A/240 V~
- Voltmeter (AC)
- 110-240 V~ 50/60 Hz
- Voltmeter accuracy
- ±2%
- Ammeter (AC)
- 0 - 80A
- Ammeter accuracy
- ±2 % (2 - 50 A), ±2 % (1 - 2 A), ±5 % (0 - 1 A)
- Compatible current transformers
- * CT 50A (included in the package) * CT 80A
- Power and energy meters
- * Active and apparent power * Active and apparent energy * Power factor * Fundamental active and fundamental reactive energy
- Channel-to-channel calibration minimum load
- 500 W
- No load threshold
- 30 VA per channel
- Measurement data storage
- At least 10 days of 1 min data resolution
- Data export
- * CSV for PQ recorded values * JSON format export through RPC
- Internal-temperature sensor
- Yes
- CPU
- ESP-Shelly-C38F
- Flash
- 8 MB
- Schedules
- Yes
- Webhooks (URL actions)
- 20 with 5 URLs per hook
- Scripting
- Yes
- MQTT
- Yes
- Encryption
- Yes (Transport level)
- Authentication
- Yes (Application and transport level)
Common questions
Quick answers before you buy. We test this gear ourselves. Can't find yours? Ask our Melbourne team
It's a split ring that closes around a live conductor and reads the current passing through it without being wired into the circuit. A 50 A clamp comes in the box. An 80 A clamp is available separately if you need the full range.
Yes. It has two current transformer inputs, so one meter can read two circuits with a second clamp added.
Not on its own. The relay is a dry contact rated 2 A at 240 V, which is meant to drive a contactor rather than carry a load itself. Your electrician wires the contactor to do the switching.
Yes. It's mains powered at 110 to 240 V and needs both a live and a neutral at the install point.
Yes. It's mains work, and fitting a clamp means opening up a switchboard or a wall box. In Australia that must be done by a licensed electrician.
Shelly · EM Gen3 Energy Meter