The tracking phenomenon is basically a carbonaceous process, which occurs at the surface of the insulating material during operation. Epoxy nanocomposites have high tracking resistance. Tracking studies were carried out by adopting IEC-587 standards. An attempt has been made to characterize the UHF signal radiated due to discharges during tracking studies. Percentage of clay content in epoxy nanocomposites has not showed any variation in UHF signal generated. It is observed that surface discharges radiates UHF signal with its frequency content lies in the range of 1-3 GHz and at the time of tracking it is in the range of 1-2 GHz. Zero span analysis of UHF signal by using spectrum analyser could help one to identify the point of transition from surface discharge to tracking condition. © 2011 IEEE.