Kyle, I had a red bias wire burn through when I built my first 400. There were several broken strands at the backplane board from stressing them during assembly, and yes, I probably nicked them when stripping. I should have secured them in a bundle with a zip tie. If you check out photos of Perry's builds you'll see his technique.
I have reduced this issue by using Phoenix Contact Connectors on the backplanes and control board for those fine gauge wires.