text: Electricity is the migration of free electrons form a highly negatively charged area to a positively charged area. When you rub your woolly socked feet on the wood floor and touch your your sister's ear, she gets a shock because you built up a negative charge compared to her charge level. so the electrons jumped over from you to her. These electrons can flow along any medium including air, as in Lightening. Even through space if the forces were strong enough. When you send electricity through a wire, the resistance of the wire and the wire itself absorb the free electron charge. It can go as far as the strength, or voltage, of the charge will push it against the resistance. We used to send phone messages across the oceans by wire so the longest we've done here on earth could be considered as many times the circumference of the earth. In short, there is really no limit as to how far you can transmit an electrical current. It will just take a lot more power to send it farther.