Sunplug
Setup guides → Shelly meters
Shelly grid meter
Not an inverter — a meter. Some inverters can only report what they produce, which is not enough to charge on surplus: you need to know what the house is doing too. A Shelly clamped at your supply point fills that gap for well under a hundred euros and works with any inverter.
Exercised against a Gen2 RPC simulator, including the sign convention on the grid clamp. No physical Shelly yet.
Do you need one?
Only if your inverter cannot see household consumption. Sunplug tells you: connect your inverter first, and if it reports production only, a grid meter section appears with an explanation. Fronius without a Smart Meter, SolarEdge without a consumption meter, and Growatt are the usual cases.
Fitting it
The clamp goes around the live conductor at your supply point, inside the consumer unit. That is electrician work in most countries and certainly not something to attempt while the board is live. This guide covers connecting one that is already fitted.
Connecting
- Find the Shelly's address in the Shelly app, or let the agent discover it
- Settings → Equipment → grid meter → Shelly energy meter
- Enter the address
- Check it works — it should show import or export matching reality
If the direction is wrong
CT clamps get fitted the wrong way round often enough that Sunplug has a setting for it rather than assuming. If export shows as import, switch the clamp direction to "reversed" — no need to touch the wiring.
The quick test: on a sunny afternoon with the cars unplugged, you should be exporting. If Sunplug says you are importing, flip it.
How it pairs with your inverter
Sunplug reads both together and does the arithmetic: production from the inverter, import and export from the Shelly, and household consumption follows from the two. Neither is polled faster than the slower of them can answer.
When it does not work
Cannot reach it
Give the Shelly a fixed address on your router. They move around otherwise, and a meter that changed address looks exactly like one that broke.
Readings are half what they should be
On a three-phase supply with a single-phase meter, you are measuring one leg. A 3EM measures all three.
Stuck? Email me.