The electrified fence would not have burned the kites or killed anyone unless there was a ground. The Japanese officer wouldn't have been able to make it spark by touching it with a stick, for example, unless the stick could conduct current, and then it would have harmed him by electricity flowing through his body and to the ground. Similarly, the boy climbing the fence wouldn't have been killed because he was not grounded (unless of course separate strands of wire had different electrical potential and were each insulated).
Modern Air Conditioning Unit shown in clip, as his wife & children are leaving in the Car.