Theoritcaly(aka a guess from a highschooler) from what i do know from digital electronics, Electricity travels at a rate of a few inches per second or something similar, its just that when you flip a switch, the electron "pushes" the over electrons into motion, causing an instant result of the light turning on. However because there is no matter in space for electrons to push, the damage would be unnoticeable and would be difficult to direct the attack at a specific target.
But I'm not exactly an expert so dont use my opinion in any tests....