Ans: Measure the actual length of the wire run to get the distance for wire size selection between the main panel and the subpanel. A thicker wire gauge is needed to compensate for the increased resistance and voltage drop that come with longer distances. When selecting the proper wire size for the 50-amp subpanel, consider these factors and any specific guidelines regarding voltage drop limits based on distance, which can be found in the National Electrical Code (NEC) or local codes.