I am actually searching for a ready to install plug (into outlet - “stopcontact”). My LEO irrigation pump has a 220v plug.
The pump has an automatic pressure switch which will kick in the pump, if the pressure after the switch drops below a certain value. To know that the pump is running, I want to install a watt usage monitor.
This will be a safety feature. If there is a piping breakup or leakage, the pump will have an uncommanded action. Combining this in a flow, I can switch off the pump.
Your solution will be a final resort. I will have to install a separete box with separate wiring.