I use the charge point (forget the model... High current version) and it doesn't like the 4 gauge wire that I ran. (got it on sale end of the roll)... Because I'm only running at 32a I don't mind(totally against code) trimming enough strands/cores to snugly fit the screw terminal on the evse. The correct move would be a junction with a suitable bus bar connector as you suggest... but I'm taking the charger/circuit with me when I move to somewhere I can put it on a 60-80 amp breaker safely... so not worried. The wire is super duper overkill in my case and not the weakest link.