This paper presents an evaluation of the performance of power circuit breakers (CBs) using direct digital sampling and the signal processing techniques applied to antenna signals obtained from the arc created during the switching process. Some researches have shown that arcing produces impulsive radio-frequency radiation. Therefore, from timing analysis of the received and recorded impulses, the switching times of circuit breakers can be measured and utilized in order to ensure the safe operation and reliability of these equipments. Results of this analysis are shown for field measurements realized on CBs attached to capacitor banks and shunt reactors of substations of CEEE-GT, in southern Brazil.