'The first recorded EMP incident accompanied a high-altitude nuclear test over the South Pacific and resulted in power system failures as far away as Hawaii. A large device detonated at 400–500 km over Kansas would affect all of CONUS.' [CONUS= continental United States]
At contrast to this is the more conventional explosive energized EMP weapon. this is also a much smaller size. To see the device and its affect on a Taurus, check out THIS link.
There is reason to believe these devices could be used by terrorists. Designs of critical facilities should consider proper protection such as Faraday cages, etc.
