Shown here is a chart with some of the most common NEMA connectors, including the common 1-15P and 5-15P (residential 2 and 3 prong plugs). The first number in a NEMA connector represents a specific connector type and voltage rating; the second number dictates the maximum ampacity it is designed for. Each connector number will be followed by a “P” or “R” meaning either “Plug” or “Receptacle.” For example, a NEMA 5-15P translates to a: 3 Prong, 120 VAC, 15 A, Plug.