The Xfmr Pro App is a utility application developed to assist electrical engineers and electricians with the task of connecting electric transformers according the National Electrical Code (NEC). This application is designed to calculate the Primary and Secondary Full Load Amps (FLA) for industry standard sized single phase and three phase transformers 600 volts and less. Using this, the utility application then sizes the minimum breaker sizes needed based on multipliers that are user adjustable in the ranges allowed by Table 450.3(B) of the NEC. The utility application then sizes the minimum required conductor sizes and conduit sizes, according to the NEC, based on the type of conductor insulation and type of conduit specified by the user in the application settings.