What is the minimum size THHN feeder circuit conductors required for a circuit with 80 amperes of continuous load?

To determine the minimum size THHN feeder circuit conductors for a continuous load of 80 amperes, we need to apply the National Electrical Code (NEC) guidelines. For continuous loads, the conductor sizing must account for 125% of the load to ensure safe and efficient operation.

First, we calculate the total load based on the continuous load requirement:

80 amperes (continuous load) × 1.25 = 100 amperes.

Now, we refer to the NEC tables regarding THHN conductor sizes to find the appropriate gauge that can safely handle 100 amperes. According to Table 310.16, a 1/0 AWG copper conductor can carry up to 120 amperes in a typical installation condition, which meets the requirement for carrying 100 amperes safely without overheating.

While larger sizes may be available and capable of handling the load, the objective here is to identify the minimum size that satisfies the NEC guidelines. Thus, 1/0 AWG is indeed the minimum conductor size necessary for a continuous 80 amp load, ensuring both safety and compliance with code requirements.