How this is put together. The three phase totals are measured, by a clamp on each incoming phase. The circuit names are declared by the electrician against the board at install. Anything left over once the declared circuits are subtracted is the residual, and that is what gets labelled unidentified: we know exactly how much of it there is and which phase it sits on, and nothing at all about what it is.

A clamp on the incomer can never name an appliance. That is not a gap in the service, it is the part of the job that needs a sparky at the board — which is why this diagram is worth something to you and nothing to a call centre.