Fundamental Code Calculations Practice Test

To determine the minimum size copper THW grounded service entrance conductor for a dwelling with a 75-amp load, it’s important to reference the National Electrical Code (NEC) guidelines. Specifically, Section 310.15(B)(16) provides the ampacity ratings for conductors.

For copper conductors, the minimum size required is based on the continuous load. In this case, a 75-amp load typically requires a conductor that can safely handle that amount of current without overheating. According to the NEC, for a 75-amp load, a 4 AWG copper THW conductor is sufficient, as it has an ampacity that can safely handle the current while adhering to the code requirements.

Using a conductor that is too small could lead to overheating and potential fire hazards, while using a sufficiently sized conductor ensures safety and compliance with electrical standards. Thus, the 4 AWG THW copper grounded service entrance conductor is the ideal choice as it meets the necessary criteria for safely carrying a 75-amp load.