Safely Driving Nails Into Roof
Typically if there are any wires in the attic attached to the roof framing, they will be on the underside of the rafters well separated from the surface you are planning on installing the roof anchors.

The only wires I could ever think would be of concern are wires that would run to an attic light. They will be attached to the sides of the rafters well below where nail points will be that you will be driving. All other wires would be in the ceiling joists for room lighting, etc.