Shelly Pro 3EM (120A) - WiFi, LAN & Bluetooth 3-phase Smart Energy Meter, DIN-rail mountable, Real-time Voltage Amps Monitoring via app, No Hub Required, Solar/Net Metering

It’s very good only complaint is that the cable clamp could be larger would not fit on a 16mm supply cable

I connected one ct clamp to live power in from grid and one to live power in from pv out to grid , I put a plug on mains supply , Works great and seems very accurate . This is one of the best I have tried with a very good app on tablet and phone

Using this to monitor incoming power and also EV charger power, Home assistant is outputing 2 graphs showing house usage without the EV usage showing, the Monitor cable was a little short so extened it by 3m testing it on a kettle before and after the extension incase of any issues with monitoring over a longer distance, no issues with the 3.6m cable now

Added this to monitor two circuits within my home to give me more granular power consumption, works perfectly with the Shelly Home Assistant integration.If you have a bus bar within your distribution board it will probably obstruct it which will mean either cutting down the bus bar so you have free space at the end or installing in a separate box as I have.

There are two primary functions of an energy meter:1. It should tell you how much energy is currently being used2. It should provide totals of how much energy was used in the pastThis device provides totals divided into time periods of 60 seconds, which would be great if you can access it without critical performance issues.Querying for the range of historical data that's present will take longer and longer the more data is stored. Eventually after 60 days it will take over 12 seconds for the device to respond, and it all it usually has to do is return 2 numbers: the oldest record timestamp and the number of 60-second records. While it's doing this it's unable to respond to queries for how much energy is currently being used because all of the API requests are processed sequentially (which is reasonable except it relies on all requests being processed quickly).Querying individual records takes almost a whole second too, which isn't ideal when I want to graph the energy currently being used every second.The outcome is that you can't reliably retrieve all of the historical data from the device because of this poor performance, and you definitely can't make graphs of your usage at the same time because it can only respond to your queries sequentially.If you can cope with not being able to reliably retrieve historical data, it can provide the 60-second usage totals as WebSocket events without impacting performance.The manufacturer refuses to fix this because the developers claim it can't be fixed.