Fuses for each power source vs one big fuse?

[Doxmia]

Currently my setup is going into an ANL fuse distribution block where the top is a bus bar and you can install 4 ANL fuses and hookup to the bottom. I've noticed my inverter post on the distribution block gets quite hot while charging making me think the bus bar is a little too undersized for my use case. As everything is currently wired and sized very specifically in a perfect world I would just rip that out, install a blue sea bus bar and run 4 individual fuse holders to each source but I do not have the space for that.

Would it be acceptable to do one larger 400-450A ANL fuse -> the bus bar and then connect sources directly to the bus bar? I'd rather fuse everything individually but given the tight quarters of where I have the distribution happening I can't find a "safe" way to do it (short of cramming everything together way too tightly).

 

[BentleyJ]

Fuses and breakers should be sized to approx. 125% of the amperage rating of the wire and other hardware in that circuit which you intend to protect. If you have 4 wires coming in to a bus bar that are each rated for 60A but you use 1 x 250A fuse on the outgoing wire then the 4 circuits coming into the bus bar essentially have no over current protection.

 

[rmaddy]

A fuse is there to protect the wire. If you put a fuse on a wire and the fuse is rated higher than what the wire can safely carry then the fuse is worthless.

Putting a 400A fuse on a bus bar that is only rated for 300A, for example, is bad. You just added a worthless fuse that will sit there and smile while the bus bar melts and starts fires.

Choose wires that safely carry the needed current and then properly fuse the chosen wires.

 

[John Frum]

Would it be acceptable to do one larger 400-450A ANL fuse -> the bus bar and then connect sources directly to the bus bar?

A 450 amp fuse requires 250MCM pure copper wire with insulation rated for 90C.
250MCM is the next size up from 4/0 awg and is rarely used for our application.