I have a 2002 ,400 4×4 I have owned since it was new. Recently,it has started blowing ignition fuses. I have looked for bare wires and tested for overcharging while running. Any guesses are welcome.

That’s got a Suzuki engine and components. Same as the 400 Eiger. Assuming you don’t have a hot wire going to ground, I would look at the voltage regulator / rectifier…see if it’s hot. They will take out a fuse when they go bad. Also get a backfire.

I have a 2002 375 and a mouse chewed the wires right below the fuse block behind the battery. I was having the same issue you are.

Sounds very possible! I will check, thank you.

Sounds like a grounding issue

Any aftermarket accessories on it? If so unhook them. Check everything that was said before. Double check battery terminals are tight and clean. When does it blow the fuse? Key on? While starting? Running for a little, lights on? Brakes on? Guessing it has a brake light.

No new aftermarket parts. New voltage regulator from my very trustworthy ATV repair shop last winter and a Warn winch that I installed over 20 years ago. 1st time, I was sitting idle and it just quit. Blown ignition fuse, replaced fuse, good to go - for a mile or so. 2nd time,blew every 10 amp fuse I had as soon as I turned the ignition on. Hauled it to the house. Under the suggestion of my ATV shop, I removed the ignition switch and checked for a bare wire- nothing. I put a 20amp fuse in hoping to burn the wire in half so I could find it - no luck. I'm hauling it in from the woods tomorrow and going to check all around the battery and fuse block.

Might want to unplug stuff till u find the issue if u don't find any bare wires.

I had to have the stater replaced on my 2002 AC 400... have no clue if that could be a part of your problem...

I've replaced the stator in practically every fourwheeler and snowmobile I've owned at one time or another... including a couple Arctic Cat ATVs. They can cause some funky issues when they are going, but blowing ignition fuses isn't one I've had. USUALLY when a stator is going it will work cold and then die when the motor gets hot, once it cools down again it will often work again. Sounds like a wire to me. I had a bad wire on my 2016 Arctic Cat last year. Would blow the Main fuse (30 amp) and kill all power to everything. Did it twice in about twenty feet, then worked for a few hundred miles, then did it again, then worked for a couple days, then did it again and would do it every time a turned the key on... until I towed it home and into the shop, then it started up and ran fine for a few miles. Ended up pulling the whole wiring harness out and untaping it all and checking it, found two bare wires in the middle of the bundle of wires, inside of the corrugated wire tubing, not where they were rubbing on anything, except possibly each other? It was a major project, but after cutting and splicing those two wires I've put an additional 3-4000 miles on it without an issue. (at least no blown fuses, I've had other issues like the secondary clutch going)

Update:
I took the battery out yesterday and found a couple bare wires (mouse chewed) and a chewed,bare battery ground wire. I replaced everything and it SEEMINGLY solved my issue. Gonna give it a long test ride today, thank you to everyone who responded.