This document is a case study that compares DC arc flash results against hand calculations based on DGUV Information 203-077. It details the comparison of ETAP Electrical Arc Energy results with hand calculations for a specific UPS system, which has a prospective short-circuit current of 4.086 kA and an intermediate circuit voltage of 400V. The study outlines the parameters used for the calculations, including the conductor spacing and current limiting factors. The results indicate a maximum deviation of approximately 0.65% between the ETAP results and the hand calculations. The document includes tables that summarize the differences in electrical arc energy, short circuit power, electric arc power, normalized arc power, and current limitations. Additionally, it presents the PPEaA protection levels at the point of arcing. The findings are supported by figures illustrating the one-line diagram and arc flash labels based on the results.