Overview#
The Generac SG300 is a 300 kW standby (270 kW prime) demand response ready industrial natural gas generator set powered by Generac's 14.2L inline-6 turbocharged and aftercooled spark-ignited engine at its highest BMEP output. Rated at 375 kVA standby at 60 Hz, it is EPA certified for both stationary emergency and non-emergency applications. Available in three-phase configurations only, it features the Generac Power Zone Pro Sync controller with a 7-inch color touchscreen display.
Engine and alternator#
The Generac 14.2L (864 cubic inch) inline-6 turbocharged/aftercooled engine delivers 300 kW standby at 448 hp and 227 psi BMEP at 1,800 RPM — the highest BMEP in the 14.2L SG-series family. The engine has a 9.5:1 compression ratio, ductile iron crankshaft and cylinder liners, cast iron cylinder head, 7 main bearings, solid lifters, and high-temperature steel alloy exhaust valves with hardened valve seats. The 24V DC electrical system uses dual 12V batteries. Oil capacity is 36.2 quarts (34.3 L).
The standard alternator is the Generac K0300124Y21, a 4-pole revolving-field design with Class H insulation on both rotor and stator, shared with the SG275. It features permanent magnet excitation, full digital voltage regulation with plus or minus 0.25% steady-state accuracy, and total harmonic distortion below 5%.
Power ratings and fuel consumption#
At 277/480V three-phase and 0.8 power factor, the SG300 delivers 300 kW standby / 270 kW prime (452 A / 406 A). No single-phase configuration is available on this model.
Natural gas consumption at standby/demand response ratings: 3,420 scfh at 100% load, 2,700 scfh at 75%, 1,980 scfh at 50%, and 1,260 scfh at 25% load.
Physical dimensions#
The open set measures 136.0 x 57.1 x 67.9 inches (3,454 x 1,450 x 1,725 mm), weighing 6,200 to 6,587 lbs — identical physical footprint to the SG275. Weather protected enclosure: 174.7 x 57.5 x 77.8 inches. Level 1 sound attenuated: 200.2 x 57.5 x 77.8 inches. Level 2 sound attenuated: 180.6 x 57.5 x 111.3 inches. Level 3 sound attenuated (steel only): 207.3 x 63.7 x 128.9 inches.
Our service experience#
The SG300 is the highest-output 14.2L inline-6 model in the SG series. At 227 psi BMEP and 1,415 degrees F exhaust temperature, this is the most thermally stressed configuration of the platform — exhaust valve condition monitoring and tighter turbocharger inspection intervals are advisable. The identical physical footprint and same alternator code as the SG275 simplifies installation planning when both models are in scope. This model marks the practical ceiling of the 14.2L inline-6 platform; higher outputs require the 21.9L or 25.8L V12 platforms.
