I am NOT a sparky. So my observations might be wrong but.......if i were running two 10mm cables i would be running half the machines off one and half of the other as they will terminate on their own fuse.Twin run: that's an odd one! Redundancy is great, if one cable fails you've got the other one...but both must be rated at individual capacity. Doubling up at lower ratings is not redundancy, it's spreading capacity over two circuits. Problem is, if one fails you won't know until you exceed the single rating....and that could be dangerous
Sensible or not???