What do the numbers with the "R" after them on the NEMA chart represent?

The designation with "R" after the numbers on the NEMA chart specifically indicates "Receptacle." This labeling is part of the NEMA (National Electrical Manufacturers Association) system, which classifies various configurations of plugs and receptacles to ensure compatibility and safety in electrical connections.

Receptacles are the fixed devices mounted in walls, floors, or any other surfaces that accept specific plugs. They are designed to fit specific types of cord caps or plugs to ensure that electrical devices are safely connected to power sources. The "R" helps to easily identify and differentiate these receptacles from other types of configurations on the chart.

Overall, the clarity provided by this classification aids electricians, engineers, and service technicians in selecting the correct components for various electrical applications, ensuring both functionality and safety.