VFD cable article

[Voicecoil]

. I don't know if these VD cables are constructed as three twisted pairs but for minimal noise radiation they would need to be.

From what I read it's more of 2 interleaved twisted triplets - a bit like 1.5x the starquad cable the BBC OB guys I worked with were so fond of in high noise situations. You might be right in that at 3x twisted pair would work better as far as EMI goes, it would all depend on the switching points of the VFD. However it would make the cable even more bulky and/or increase copper losses, so that's probably why it's not been done. It would be nice to investigate this further, but as no-one makes a 1mm2 such cable and it probably won't matter much on a 2.5m run, I have more important things to concentrate on.

While we're on about it, using a twisted pair rather than loose wires for connecting limit switches etc. to your BOB might help reject noise pickup even for non-balanced inputs.
Kit

I've already done this. The leads on the proximity sensors were woefully short, so had to be extended anyway, so I chopped them back to a sensible minimum length and extended with my favourite Mogami screened twisted pair cable. Why they don't make such sensors with a screened cable to start with I don't understand.