300kW generators at a glance

• Rated 300kW (375kVA) standby, typically about 270kW prime
• 451 amps at 480V, three-phase, the most common voltage at this size
• Burns about 16.1 gallons of diesel an hour at three-quarter load
• Sized for a manufacturing plant, a distribution warehouse, a hotel or a surgery center
• 60Hz units built for North American power
• New and used units in stock, shipping from Colorado, Florida and Texas

300kW generators in stock now

A workhorse for manufacturing, warehouses and larger buildings

A 300kW generator runs production equipment, warehouse HVAC and refrigeration, or a full hotel or surgery center through an outage. It’s a common size for water and wastewater plants, data rooms and larger retail centers, and two of them are often paralleled for bigger sites.

Our 300kW stock changes week to week. It usually runs from brand-new units to used standby sets from Cummins, Generac, Multiquip, Kohler, CAT and others, almost all diesel.

Every unit is ours. We buy and own our inventory outright, so we can tell you where a generator came from, how it was used and what our technicians found when they went over it. Units ship from our yards in Brighton, Jacksonville, Pensacola and Austin, and we can get them to a site anywhere in the contiguous US, with Canada and Mexico on request.

Not sure 300kW is the right fit? Run your loads through our generator sizing calculator, or call and talk it through with someone who sizes these every day.

What a 300kW generator can power

Typical buyers include:

• Manufacturing and industrial: production lines, compressors, welders and process equipment
• Warehousing and cold storage: distribution centers, refrigeration and dock equipment
• Healthcare: surgery centers, smaller hospitals and large medical office buildings
• Hospitality and commercial: hotels, large retail centers and multi-story offices
• Water and municipal: water and wastewater plants, lift stations and emergency operations centers

Size for starting loads, not just running loads. Large motors, chillers and refrigeration compressors pull several times their running current for a moment when they start, and that is usually what decides whether 300kW is enough.

300kW generator specs

A 300kW standby generator is rated at 375kVA. Amps are three-phase at a 0.8 power factor, from our kVA, kW and amperage chart. Most 300kW sets are 480V; 208V and 240V are less common at this size.

Voltage (three-phase)	Amps
208V	1,041
240V	902
480V	451
600V	361

Fuel use below is estimated from our fuel consumption charts. Actual use depends on the engine and site conditions.

Load	Diesel (gal/hr)	Natural gas (ft³/hr)
1/4	6.8	1,393
1/2	11.3	2,229
3/4	16.1	3,076
Full	21.5	3,857

How 300kW compares with nearby sizes

Size	kVA	Amps at 208V	Amps at 480V	Diesel at 3/4 load (gal/hr)
250kW	313	867	376	13.6
300kW	375	1,041	451	16.1
350kW	438	1,214	526	18.7
400kW	500	1,388	601	21.3

300kW spec sheet library

Spec sheets for the 300kW models we see most often. Details can change by model year, so check the sheet against the nameplate on the exact unit you’re quoting. Need one that isn’t here? Ask and we’ll find it.

Brand	Model	Fuel	Spec sheet
CAT	3406C 300kW	Diesel	CAT 3406C 300kW spec sheet (PDF)
Cummins	C300D6R	Diesel	Cummins C300D6R spec sheet (PDF)
Cummins	DQHAB	Diesel	Cummins DQHAB spec sheet (PDF)
Generac	SD300	Diesel	Generac SD300 spec sheet (PDF)
Generac	MD300	Diesel	Generac MD300 spec sheet (PDF)
Generac	SG300	Natural gas	Generac SG300 spec sheet (PDF)
Generac	MG300	Natural gas	Generac MG300 spec sheet (PDF)
Kohler	300REOZJ	Diesel	Kohler 300REOZJ spec sheet (PDF)
MTU	DS300	Diesel	MTU DS300 spec sheet (PDF)
Olympian	G300LG4	Natural gas	Olympian G300LG4 spec sheet (PDF)
Olympian	G300LG6	Natural gas	Olympian G300LG6 spec sheet (PDF)

Browse every size in our full spec sheet library.

What’s included when you buy from us

• An inspection by our EGSA-certified technicians before the unit leaves our yard
• Load bank testing available, so you can see it carry a load before it ships
• Shipping to your site anywhere in the contiguous US, with Canada and Mexico on request
• Photos, the spec sheet and a walkaround video of the actual unit
• A deposit that holds your unit while you finalize, with a clear quote expiration date
• Service after the sale from our teams in Colorado, Florida and Texas

Watch our load bank testing

Before a unit ships we can put it on a load bank so you can see it carry load. Our YouTube channel has load bank runs on generators across the size range.

300kW generator FAQ

How many amps does a 300kW generator put out? At three-phase and a 0.8 power factor, a 300kW generator delivers about 451 amps at 480V, 361 amps at 600V, 902 amps at 240V and 1,041 amps at 208V. Your electrician will size the breaker and transfer switch from those numbers.

How much fuel does a 300kW generator use? A diesel 300kW unit burns roughly 11.3 gallons an hour at half load and 21.5 at full load. At three-quarter load that is about 386 gallons over 24 hours. On natural gas, figure about 2,229 cubic feet an hour at half load and 3,857 at full load.

Is a 300kW generator the same as 375kVA? Yes. Generators are usually rated at a 0.8 power factor, so 300kW of real power equals 375kVA. You’ll see both numbers on spec sheets and nameplates.

What’s the difference between a standby and a prime rating? A standby rating is for backup power during outages. A prime rating is for running as the main power source for long stretches, and it’s often around 10% lower, so a 300kW standby set may carry about 270kW prime. Check the spec sheet for each unit.

Can two smaller generators do the job of one 300kW unit? Yes. Two 150kW units paralleled through switchgear can share a 300kW load and give you redundancy if one goes down for service. The trade-off is the cost and complexity of the paralleling controls. We can help you compare both setups.

Should I buy new or used? Used units cost less and are often ready to ship now, while new units can carry a factory lead time. We stock both. Every used unit lists its hours and year, and we’ll send photos and a walkaround video of the actual generator before you commit.

How much does a 300kW generator cost? Price depends on whether it’s new or used, its hours, brand, fuel type and enclosure. Tell us about your site and we’ll send pricing on every 300kW unit that fits.

Can I rent a 300kW generator instead? Yes. Our rental teams in Colorado, Florida and Texas can set you up for a short-term job, an event or while you wait on a permanent unit. See generator rentals.

Get pricing on a 300kW generator

Tell us what you’re powering and when you need it, and we’ll send pricing on every 300kW unit that fits. Call 877-866-6895, text us for a quote or request one online. Want to see the unit first? Ask for a walkaround video.