Gallium nitride (GaN) high electron mobility transistors (HEMTs) are an ideal option in applications of power electronics due to the wide-bandgap properties of the material. High electron mobility is gained through the device's unique channel structure. This research investigates whether state-of-The-Art GaN HEMT semiconductors are reliable in a long-Term operation in high power switch-mode conditions. Information on overcurrent capability about GaN HEMTs is not well established, thus a demand to investigate the devices exists. The GaN HEMT GS66508P from GaN Systems, was tested in pulsed overcurrent operations to establish the performance and to observe any operational changes after the experiment. The device is rated at 650 V and 30 A continuous. The goal of this research is to see if the device characteristics change after overcurrent pulsing and to analyze the device degradation that occurs in higher energy density.