Raymarine A/P,MFD,Radar install

[maine50]

Soon I'll be installing Raymarine A/P EV-200, Axiom Pro 9, and Quantum Radar.
I already have Raymarine st70i instruments on 3 displays. I have read that you should have only 1 power input into the Raymarine StNg backbone. The backbone will be less than 20 ft so balancing doesn't appear to be critical.
I can look at specs and figure max draw from all components and use switchboard circuit breaker for main power feed. Should there be separate fuse for each power draw? I am also concerned that if the backbone has a failure
I loose everything. How does one work around that as far as power feed goes?

What happens if you have more than 1 power feed on a backbone (raymarine)