G'day All.
It may not be general knowledge but carbon fibre will conduct power & is flammable. If there is sufficient amperage the resistance will cause combustion. Most earths are connected to the firewall. It would be an advantage if the carbon fibre firewall was not connected to earth, I am not sure how that could be achieved but if it could, it would give an extra layer of protection. A short between + & -- cable would normally trip a circuit breaker. The short between a live wire & the carbon fibre firewall can very quickly cause a fire with a current less than the trip value of a circuit breaker.
John WA