How can an Inverter and fuse block share a breaker?

[Erible]

Seems like it's common for people to run their inverter and fuse block through the same breaker to save on wiring. Will does it in one of his videos and I'm just trying to understand the setup. Here are the questions I have:

1. In Will's video, the Inverter and fuse block have the same rating; 125A. What if your fuse block and inverter have different amp ratings? Would it be best to have separate fuses or to just use a fuse for the one with a lower rating?

2. If your inverter and fuse block are EACH pulling 125A wouldn't that mean that you're pulling 250A through the shared fuse and you can blow it easier?

 

[HighTechLab]

1. If your inverter and fuse block have different amp readings, your fuse should be sized for the lower rating (If they are shared). If the fuse block is rated for 120a you wouldn't want a 200a fuse because then if you are at 150 amps on the fuse block it would cook the fuse block and start a fire without blowing the fuse. I would suggest seperate fuses for each if they are shared.

2. Exactly. Lets say you want to inverter to be protected to 100 amps max because over that would hurt the inverter. Now you have 10 amps of load on your fuse block because you turned on some lights. Now you load your inverter to 90%, you have 90 amps plus 10 amps from the fuse block and then you could blow your fuse.

 

[Erible]

Thank you!!!