Originally Posted by xtatico1404
tsweeney, you got it. Put in place fuses for the batteries. They will protect the batteries under short circuit & overcurrent conditions.
And yes, keep the fuses on each individual circuit, as well as the Main DC panel circuit breaker.
The term for what we are describing is called "selective coordination" of a protection system.
As I understand it, the reason for each of these fuses/breakers in sequence is to protect each bit of wire "downstream" from each fuse. You need a fuse at the battery to protect the wire that runs from the battery to your main buss (unless it's less than 7" or somesuch). The wire running from your buss to you panel might be a different (smaller) guage and so will require a different (smaller) fuse. The wires running from the panel to each of your fixtures will be smaller still, requiring still smaller fuses/breakers, and then fixtures (e.g. electronic instruments) may have still smaller wires in them, requiring their own fuse as well! You probably all know all this already, but the point is that it all starts at the battery, so you need fuse protection starting there, too. Am I right?