Wiring Generator Connector L5-30 - generators for home use Wiring diagram and rating of single-phase 120V/30A connector L5-30. Generator Connector L5-30. The mating 3-prong plug part number is NEMA L5-30P. How do you wire a Nema L5-30 plug - answers An L5-30P is a two pole three wire grounding 30 amp, This is a 277 volt AC plug. This will allow you to plug the new dryer cord into the old wiring.