Domakihub Install a Smart Energy Monitor in Your Home Fuse Box
Track every circuit's consumption in real time — no rewiring, no electrician required.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 5 min read
A clamp-based smart energy monitor like the Shelly EM slips around your existing live wires inside the fuse box and starts reporting watt-by-watt consumption to your phone within minutes. The video above walks through the physical installation; this article breaks down each step with the details that matter for Greek homes, holiday apartments, and small hotels — especially where ageing single-phase panels and high summer air-conditioning loads make electricity bills a constant concern. Getting visibility over your consumption is the first step to cutting it.
Why Greek Property Owners Are Installing Energy Monitors Now
Greek electricity tariffs have risen sharply since 2022, and short-term rental hosts face an additional pressure: guests run air conditioning around the clock without any cost awareness. A real-time monitor gives you hard data on which appliances or circuits are the biggest draws, so you can make targeted decisions rather than guessing.
The Shelly EM is a popular choice because it runs on Wi-Fi, integrates with the free Shelly Cloud app, and supports Home Assistant or MQTT for more advanced setups. Crucially, it uses non-invasive current transformer (CT) clamps — you clip them around a wire without cutting or splicing anything, which keeps the job legal for a DIY installation under Greek electrical regulations for low-voltage monitoring accessories.
What You Need Before You Open the Fuse Box
Gather the Shelly EM module (with the CT clamp cables included in the box), a small flathead screwdriver, a phone with the Shelly app installed, and your Wi-Fi password. You will also need to know which phases your panel uses: most Greek homes have a single-phase 230 V supply, so one Shelly EM covers the whole panel. Three-phase properties — common in larger villas or commercial premises — need either multiple units or the Shelly 3EM.
Safety first: the Shelly EM itself is powered by the panel's live voltage, so you must switch off the main breaker before attaching the power wires. The CT clamps, however, are safe to clip on while the breaker is off — they measure current magnetically without any electrical contact with the conductor.
How to Install the Shelly EM: 5 Steps
- 1
Switch off the main breaker and verify the panel is dead
Flip the main circuit breaker to OFF and use a non-contact voltage tester on the incoming terminals to confirm there is no live voltage downstream. In Greek panels the incoming supply from the meter (the DEI feed) remains live even with the main breaker off, so never touch the terminals above the breaker. Work only on the output side — the bus bars, neutral rail, and the wires feeding your individual circuit breakers.
- 2
Mount the Shelly EM inside or beside the enclosure
The Shelly EM has a compact DIN-rail footprint (35 mm standard rail). Snap it onto a free section of rail, or use the adhesive pad to fix it to the side wall of the enclosure if rail space is tight. Route the CT clamp cables so they reach the live conductors you want to monitor without straining the connector — the cables are typically 1 m long, which is ample for most Greek domestic panels.
- 3
Connect the power wires to the Shelly EM
The unit needs a permanent 110–240 V AC supply to run its Wi-Fi radio. Connect the Live (L) wire to the terminal marked L and the Neutral (N) wire to the terminal marked N, using conductors tapped from a free slot on your bus bar or from a dedicated breaker if you prefer a switched feed. Use 1.5 mm² flexible wire and make sure the terminal screws are torqued finger-tight plus a quarter turn — Greek summers cause thermal expansion that loosens loose connections over time.
- 4
Clip the CT clamps around the conductors you want to measure
Open each CT clamp and close it around the live (phase) conductor only — never around both live and neutral together, as the fields cancel and you will read zero. The clamp has an arrow indicating current direction; orient it so the arrow points away from the panel toward the load. Plug each clamp's 3.5 mm jack into channel 1 and channel 2 on the Shelly EM. You can monitor two circuits independently: for example, one clamp on the main incoming phase for total consumption and a second on the air-conditioning sub-circuit.
- 5
Power up, add the device in the Shelly app, and calibrate
Switch the main breaker back on. The Shelly EM will boot into access-point mode (look for a Wi-Fi network named shellyem-XXXXXX on your phone). Open the Shelly app, tap Add Device, and follow the prompts to join it to your home Wi-Fi. Once connected, the app displays live power in watts and accumulated energy in kWh for each channel. Turn on a known load — a 2 kW kettle is ideal — and verify the reading matches the rated wattage to within 5 %; if it reads negative, flip the CT clamp 180 degrees on the wire.
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FAQ
- Do I need a licensed electrician to install a Shelly EM in Greece?
- The Shelly EM connects to your panel's supply voltage for power, which technically counts as electrical work. For peace of mind and insurance validity, having a licensed electrician (adeiodotimenos ilektrologos) perform or supervise the connection to the live terminals is the safest route. The CT clamp part — clipping around the wire — is non-invasive and carries no shock risk when the breaker is off, so many owners handle that portion themselves.
- Can I monitor a three-phase supply in a large villa or hotel?
- Yes, but the standard Shelly EM only handles two channels (two CT clamps). For a full three-phase setup you need the Shelly 3EM, which provides three independent CT inputs and calculates total three-phase consumption. Both devices use the same Shelly Cloud app and local API, so the setup process is nearly identical.
- Will the monitor work during power outages or if the Wi-Fi drops?
- The Shelly EM requires its own power supply to operate, so during a grid outage it goes offline along with everything else. If your Wi-Fi router drops but grid power stays on, the device keeps recording locally in a short buffer and syncs historical data once the connection is restored. For holiday rentals where you monitor remotely, pairing the router with a small UPS ensures the Shelly EM stays reachable even during brief local outages.