Can anyone help me on this matter. As far as I know there is no regulations on this or wrong or right way to do it but when labelling a 3phase board I have always done it bottom left up then bottom right up so for example from the main switch on the left side been 1l1 up to 12l1 then on the bottom right start 13l1 up to 24l1 at the top. I have always been told to do it this way and see it as a good common practaice as on single phase boards your first cct always starts next to the main sw/ RCD so why change it for 3phase?? But on doing some work for another sparky today he does it from the top down and he was adamant that I was doing it wrong and it was not up to regs? So anyone of you come across this before I often go to jobs and 3 phase boards are labeled any how so to me it seems each to their owe and there isn't a reg for it!