Its amazing how many tit bits one doesn't know, don't ya know !
If I put sockets inside kitchen base units that are wired to TWE that is at some point fixed to the wall, there may be some "loose" TWE "hanging" across the wiring void between the wall and the units.
In other words, some length of unrestrained cable.
I cannot think how this could be avoided, but is it OK ?

Also what about loose TWE draped across the floor behind / under the units. That seems like poor form, but I have seen it in "pro" installations.

Simon.