There are a number of “standards”, but e.g. Liebherr are using 6kV for their newer small electrified excavation equipment. Cable size obviously varies based on

There are a number of “standards”, but e.g. Liebherr are using 6kV for their newer small electrified excavation equipment. Cable size obviously varies based on the needs of the equipment, but “not small”, and yes, they are routinely surface-laid around the site. Larger sites do the predictable step-down thing to reduce IR losses. Many of these systems have been around for quite a while, but the move into smaller scale (sub-100t) gear seems to be picking up.