L14-30R outlet
The L14-30R is the standard 30-amp, 120/240-volt twist-lock receptacle found on most mid-size portable generators. It carries up to 7,200 watts through a single cord and is the usual connection point for a transfer switch or interlock.
The naming decodes as: L = locking (the plug twists in and cannot vibrate loose), 14 = the 125/250 V four-wire configuration (two hots, neutral, ground), 30 = 30 amps, R = receptacle. The matching plug is an L14-30P.
Because it delivers both 120 V legs and 240 V, the L14-30 can feed an entire small panel through a generator inlet. A generator with only 120 V outlets (L5-30, 5-20) cannot run 240 V appliances like well pumps or dryers regardless of wattage.