Or just a normal electricity meter (energy meter). Available everywhere. Intended for billing, accurate within a few %. Cost for a 3-phase model is something around $100, though. Maybe you could find a used unit, even an old mechanical.
If you want actual logging, these have at least a blinking LED you can optically couple to, and many have open collector optoisolated pulse output for easy interfacing with any logging system. One pulse per Wh or similar.