I can't help but think of a Steak-N-Shake ad where they say "Look at the pictures".
http://www.cooperindustries.com/content/public/en/wiring_devices/products/receptacles/commercial/_20a/nema_5_20r/commercial_grade_receptacles_20a_125v_nema_5_20r_br20_cr20_1877.htmlYes all of the NEMA types describe single connectors. If you have a duplex it would be a dual 1-15 or dual 1-20, for example.
Well a Nema 5-20R can be a single or a duplex??
It is a code for the rated voltage and number of poles, though I'm not sure just how it came about.So what does the # before the -30r etc. in the chart represent?