This confuses me. First, 2/0 welding cable can handle 300 amps. Second, I thought the whole idea of an oversized fuse was to not have nuisance blows but to have protection in case a major inrush happens from a short.
This also confused me for a long time too.
You can’t simply say, “2/0 can handle 300A”. It can, but only IF the insulation jacket is rated for a temperature of 105C and it’s a short run of cable. If you use cheaper 75C cable, it’s only good for 175A.
The other part is you don’t fuse to avoid “nuisance blows”, you fuse for less than the amp rating of your cable. If you use
105C 2/0 copper cable, use a 300A fuse, if 75C, use a 150A fuse. Be sure to check the exact specs of the copper cable you intend to use before sizing the fuse.
Now if you do get get nuisance blows, then your inverter is sized too large for your cable and fuse. Either get a smaller inverter or size up cabling and fuse. Sizing up cabling could mean going to a thicker gauge or simply higher temp rating insulation.
At that point, even a large fuse is going to blow before it damages the wires.
Maybe? But that’sa guessing game. You don’t want to guess that a “large fuse” is going to protect you. Ya gotta do the math properly. The ONLY thing the fuse is designed to protect is the cable it’s fused on. It’s to prevent fires, nothing else. If you place a 300A fuse on cable that’s rated for 150A (but you think is rated for 300A), you’re literally playing with fire.
Quality wire has the temperature rating in Celsius written on the insulation.