What would cause the ECU fuse under dash to keep blowing?

98 SOHC. This customer's car has some cheap plug wires and he had a problem with a misfire. Turns out one wire was up against the exhaust, burning and shorting. Replaced it with a spare he had in the back just to diagnose. It was pulled apart when somebody pulled it before, so I stripped and recrimped. I had to cut a slit in the boot to do this. Anyway, had to do this to another wire afterwards too.

So I'm wondering if this has anything to do with the fuses blowing, maybe there is an arc going through the boot? Possible? Any other ideas?