Mick D wrote: Tosh
Wires are designed as multi core with the intention of being able to be routed around corners, once in place they experience no stress unless they move, which in this case they won't. I think you're over thinking this.
Regards Mick
Never been too good at explaining my thoughts ... Not so much over thinking as understating what I see as the problem .. due to the restricted area, the bends will be tight (particularly inside the bars), forcing the wire hard against the lips of the hole .. outside, to a degree, can be rounded off/countersunk, but inside it will be very difficult to remove the sharp edge left by the drill, which would easily wear through the insulation of the wire.