My jumper leads are the cheap clamps and 00 gauge PTFE covered cable. I have used it to jump start with a totally dead battery, and while the connectors smoked the cable did not.
Did one night jump start an ambulance using the ground power unit, luckily they were close enough so I did not have to move the truck, just unwind the 28V leads and jam the cheap jump leads into the socket ends on the cabling. Lighting on the ambo went from dim to bright instantly, and it started on the first turn of the starter. 24V battery was quite happy with 28V, though I could not see any current draw on the ammeter, full scale is 8kA. Plug some aircraft into it and you do get the peak coming very close to that. Funny enough not big aircraft either. You just need a big jet engine with a starter/generator bolted to the front of it. It can charge at that rate too.........