DC Microgrid is beneficial compared to its AC counterpart due to its better efficiency and controllability. However., lack of standards and absence zero crossing in fault current limits its wide application and future growth. Further, filter capacitor discharge during fault asks for a faster fault detection technique. Moreover, the change in fault current is limited due to the fault resistance. Hence, it is imperative to design a faster fault detection scheme that can identify small changes in fault current. Therefore, this article proposes a new fault detection scheme based on cumulative energy derived from relay current utilizing Discrete Wavelet Transform. Further, the efficacy of proposed methodology is verified using a 510 V, 25 kW DC microgrid which is simulated in MATLAB/Simulink. The proposed method is verified for various scenarios including load change, sudden switching, high resistance fault, and with noise. The test result reveals that proposed method accurately detects the fault within 3 ms up to 50 Ω fault resistance.