Choosing the wrong cable conductor size isn't just an inefficiency—it's a fire hazard. Here is the engineering rule you need to know:
: Over long distances, a wire that is too thin will "steal" voltage. For a standard 120V system, the minimum voltage must stay above 108V. If the wire is undersized, an appliance at the end of the line might not even start. cable conductor size
: The giant that brings power from the street into your main panel . Choosing the wrong cable conductor size isn't just