Quick question re fuse size

[Bluedog225]

I’m finally wiring up my Victron 12/1200 on my SOK 200 amp battery.

Coming to terms with the 100 amps. I’ll probably not approach that power use but need to wire it up properly. Shop lighting, light tools, fan, etc.

Blue Sea tells me 4awg. Fine.

Can I use my 225 amp class T fuse on this wire at the battery? Or do I need something smaller? I don’t know what the rule of thumb is for sizing fuses to wire.

Ps-the inverter is fused separately also.

Thanks

 

[DIYrich]

4awg is 60 amps in conduit, and 135 amps in open air. If short, you may be able to push to 150 amps. 225amp fuse will not protect the wire.

 

[Bluedog225]

Ok. Thanks. It’s open air and about 14” long. If that matters.

The chart I looked at wasn’t all that helpful on very short runs.

 

[400bird]

A 225 amp fuse is better than no fuse. The wire might it be unusable after a 250 amp short but the fuse should open before the insulation bursts into flames. I can't say the same for anything else the wire/insulation touches.
As the wire gets hotter, the fuse gets hotter, which increases it's resistance, which increases temp, which increases... Well you get the point, hot wire=hot fuse=open fuse.

I'd recommend buying the proper fuse.

 

[Bluedog225]

Is there a handy wire to fuse size table? Or guidance? Thanks