I doubt whether the Council would happy with the situation either if he has people living in the van parked on the street. They also wouldn't be too happy about power lines across the footpath. It might be worth contacting your council about the matter and they could send out a ranger to deal with it. If he is using OC electricity then he should have to pay for it. Air conditioning isn't cheap to run, particularly in poorly insulated situations like a caravan. You should have a look at your electricity bills and see how much he's costing you, normally OC electricity for a few lights wouldn't be much.
I don't think you're being a meany at all, and should pull the plug on him. The correct place for his van is a van park, not the street or common property.