You will need an accurate meter to benchmark the device against it, and input the offset as a percentage in the Settings (Specific) menu. I've been told I need a CT clamp based monitor but the recommended products (OWL Micro+ and OWL +USB) don't seem to be available. The monitor connects to mains power of the 1 phase system in the electricity box, as such a professional electrician may be required for installation.

As usual, I’m going to disassemble the device, install and test it’s usage and integrate it in Home Assistant. I don’t have much experience with CTs and I found no specific instructions as how to put the meter on the wire.So you can use it to monitor individual circuits (if you are happy with going inside your CU), but you need to purchase the 150A model of this product if you want to monitor your whole house supply.

Quick update on this: an acquaintance on an electrician forum sent me an OWL but s got the wrong sensor, so on the look out for the right one. Inter-Technology Harmony: Dive into real-life scenarios that showcase how different technologies can coexist and complement each other, amplifying your smart home's potential. The unit was a set of clamps and a separate display which I connected up to a PC program for logging purposes. If your unit is reading inaccurate measurements, good news is they can be completely calibrated within Zigbee2MQTT.The best way to calibrate it is to attach the clamp around a cable with a known current running through it.