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Guess I should have saved myself the time and just went ahead, got a larger tester and found out for myself. So much for the friendliness of fellow diesel heads. lol
Don't lump us all into one group because you didn't get an answer you liked. I was wondering why you haven't just measured the draw with a clamp-on tester. No substitute for your specific conditions. Shoot, put fuse holder on there and play with various fuse values until you don't blow one. Cheers!
 

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Don't lump us all into one group because you didn't get an answer you liked. I was wondering why you haven't just measured the draw with a clamp-on tester. No substitute for your specific conditions. Shoot, put fuse holder on there and play with various fuse values until you don't blow one. Cheers!
True point, didn't mean to lump all.

I'm just surprised more haven't heard of IP fuses and of others doing this. It is a requirement on many boats and some race circuits when you place the battery in a remote location especially if it is where your fuel cell is.... I did find a neat ignition protection breaker that self resets but I like when on stays off until I reset personally.
Del City Marine Rated Auto Reset, Surface Mount - 3/8" Stud

I just know diesels having a higher compression than gas I would assume would take more amps to crank. Just hated to buy the larger tester to only use that rating twice. lol

Patrick your suggestion is maybe the most cost effective, I'll just buy a mega holder that has a high rating and then start with lower rated fuses until I find one that is stable that will blow before too much welding happens downstream if the main is damaged.
 

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I would just check the gauge of the cable going to the starter and or whatever you want to protect and then find out the amp load of that gauge of wire.

Then fuse it accordingly. You can either fuse it for what the wire will carry or undersized the fuse for more protection.
 
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For the main B+ cable a short will be HUGE amperage. I would go 500A fuse. A chafe will often burn few strands and it's done but a good contact will be more than enough to pop a 500A fuse and not blow it one cold day when you need to get it to run. Without measuring, from long experience diagnosing starter problems I would expect 180-220A continuous draw and double that (450A+/-) for the initial short surge to get engine turning if starter has to overcome a TDC compression stroke. Surge might even pass 500A but fuses, even fast blow take a few ms to heat and melt so you shouldn't have issues. If the battery is much below full charge then you may have a longer more labored initial starter motion and that can send the surge amperage much higher. Likely not a big risk as it sounds like you are diligent. The way your type fears are handled on lots of machinery is with cable protecting sheath. The last I picked up is Techflex brand and I got it at my residential/industrial electric supply house. It is a woven tubular material and it offers abrasion and chafe protection to wire or wiring harness. It is often on wires on ag and construction equipment to reduce shorting risks from wires on dirty equipment and the cable insulation wearing through.
 
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Many of your comments exclude you form being any authority of any of this.
I've been diagnosing, repairing, modifying, & re-designing automotive circuits since the '80s, both professionally & as a hobby; and I passed most of the Ford electrical tests before I took the 2-week course while working at a dealership. But since you know better, I don't understand why you ever asked. Good luck with it.
 

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This thread is closed. We can do without sniping at each other.
 
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