I think this depends on what kind of wire you are talking about. If it is elecrical wires, call your utility company , They may do it, refer you to someone else or make arrangements to cut power. REMEMBER TOUCHING ANYTHING CONTACTING EIECTRICAL WIRES MIGHT KILL. I would suggest a professional do this if it is elecrical.
If the wires are something else, such as phone or cable just pprune as you normally would being sure that all cuts are either up/down or slanted and in no case cut horizontally, as water can sit on the surface and allow rot and disease to enter.