The manual for the Multiplus-II recommends a 400A fuse and 2x50mm2 cables. In the ‘wiring unlimited’ book, the battery cable table shows a max current of 150A for a 50mm2 cable. The fuse protects the cable, so why is 2x50mm2 enough for a 400A fuse here?
A little secret almost any gauge wire can carry 300A even as small as 4mm its a question of how long it can do it and how hot it till get and if the smoke will come out.
2x50mm use 2x200A fuses. From wiring unlimited the fuse type, arc quench and blow rate matter.
What makes the ability to blow the fuse is if the source of current is able to push out the power to blow it.
So if its a slow blow fuse you can use a slightly smaller one.
I suppose you got the ‘Victron Expert’ label because of the number of replies, and not the quality of the content.
It was meant to be a light hearted reply in the first paragraph. I guess my sense of humour is not yours. No matter.
The other two pargraphs have no incorrect information @Billy. What is the issue there?
I can add on a bit though.
The amperage ‘rating’ for a cable varies depending on the heat ‘allowed’ so 40°C or 90°C so cables are not just rated by amps, the wiring unlimited is a guide not an absolute standard.
So dig a little deeper and check insulation rating for your cable chosen. Open air rating as well for the cables stated in the victron manual. So much more nuanced than the cut and dried amps a cable can take.
If you put a 400A fuse on a system and the battery cannot provide those amps to blow it. Your system is unsafe