These sounds were found, or modified from sounds found, at http://www.partnersinrhyme.com/soundfx/electricsoundfx.shtml

 http://www.sound-effect.com/sounds1/electric/arc1.wav
 http://www.sound-effect.com/sounds1/electric/ESPARK1.wav
 http://www.sound-effect.com/sounds1/electric/powerlines.wav
 http://www.sound-effect.com/sounds1/noise/Squeeks2.wav