Arc flash thin sheet to cover panel cabinet & fixing the wires
I'm looking for a thin sheet of material insulator that is fireproof and arc flash proof that you can put over wood


Mica


  These sheets are chemically inert, dielectric, elastic, flexible, hydrophilic, insulating, lightweight, platy, reflective, refractive, resilient, and range in opacity from transparent to opaque. Mica is stable when exposed to electricity, light, moisture, and extreme temperatures. It has superior electrical properties as an insulator and as a dielectric, and can support an electrostatic field while dissipating minimal energy in the form of heat;


But it won't be appropriate for lining a wooden cupboard containing a dangerous main breaker box. Adding bodges over other bodges never turns a bodge into anything sane. The right solution for that is to tear everything out and rebuild that part of the installation to code.