What size RHW copper conductors are needed for a calculated load of 196 amperes using three single insulated conductors in EMT?

To determine the appropriate size of RHW copper conductors for a calculated load of 196 amperes, it's crucial to reference the National Electrical Code (NEC) which specifies the ampacity ratings for various conductor sizes and insulation types.

Based on the NEC ampacity tables, for copper conductors with RHW insulation in a typical installation scenario, a 3/0 AWG conductor is rated to handle up to 200 amperes under given conditions. This rating accommodates factors such as temperature, conductor grouping, and installation method.

Considering the calculated load of 196 amperes, selecting the 3/0 AWG size ensures that the conductors are adequately sized for the load while providing a safety margin. This is especially important in circuit design, as operating conductors near their maximum rated capacity can lead to overheating and increased risk of failure.

In contrast, the other sizes listed would not be appropriate because they either fall short of the required ampacity or do not provide sufficient capacity for the load. By selecting 3/0 AWG, you're ensuring reliability and compliance with the NEC for the specified application.