Overview#
The Cummins C350 D6 is a 350 kW standby diesel generator set powered by the QSG12-G1 — an 11.8-liter, 6-cylinder turbocharged and charge-air-cooled engine featuring Cummins' High Pressure Common Rail (HPCR) fuel injection system. Rated at 438 kVA standby and 400 kVA prime at 60 Hz, the C350D6 is designed for large commercial, industrial, and mission-critical standby applications requiring reliable power delivery with full-authority electronic engine management.
The QSG12-G1 engine is fitted with the Cummins CM2880 ECM and Cummins proprietary Power Generation Interface (PGI), providing advanced engine protection and SAE J1939 CAN-based communications. The HPCR fuel system delivers fuel injection pressures far exceeding conventional systems, enabling lower fuel consumption, reduced noise, and superior emissions performance. Two-stage Fleetguard NanoNet fuel filtration with a water-in-fuel sensor is standard, protecting injection components from contaminated fuel.
The C350D6 is rated for 50°C (122°F) ambient operation with the standard Coolpac integrated cooling package. Open skid and enclosed configurations are available.
Technical Specifications#
Power Ratings (60 Hz, 1800 rpm)
| Rating | kW | kVA |
|---|---|---|
| Standby (ESP) | 350 | 438 |
| Prime (PRP) | 320 | 400 |
Engine — Cummins QSG12-G1
| Parameter | Value |
|---|---|
| Displacement | 11.8 L (721 in³) |
| Configuration | Cast iron, inline 6-cylinder |
| Bore x Stroke | 132 mm x 144 mm |
| Aspiration | Turbocharged and charge air cooled |
| Fuel system | Cummins HPCR (High Pressure Common Rail) |
| Fuel filtration | Two-stage Fleetguard NanoNet with WIF sensor |
| Lube oil filter | Spin-on full flow filter |
| Lube oil capacity | 34.1 L |
| Rated speed | 1800 rpm |
| Starting voltage | 24V, negative ground |
| Battery charging alternator | 80 amps |
| Emissions | EPA Tier 3 |
| ECM | Cummins CM2880 |
Fuel Consumption (60 Hz standby rating)
| Load | Consumption |
|---|---|
| 50% load | ~12.2 gph |
| 75% load | ~18.2 gph |
| 100% standby | ~24.6 gph |
Physical (Open set)
| Dimension | Value |
|---|---|
| Length | 3376 mm (133 in) |
| Width | 1500 mm (59 in) |
| Height | 2103 mm (83 in) |
| Dry weight | ~3285 kg (7237 lbs) |
Cooling System (QSG12-G1 Coolpac)
| Parameter | Value |
|---|---|
| Coolant capacity | 48 L |
| Limiting ambient temperature | 50°C |
| Cooling system air flow | 7.15 m³/s |
| Cooling system design | Air-air charge cooled |
Our Service Experience#
The QSG12-G1 engine represents a significant step up in complexity from the QSB5 and QSB7 platforms — the HPCR fuel system operates at extreme injection pressures, and fuel quality is paramount. We require a clean fuel sample before commissioning any C350D6, and we recommend installing a fuel polishing system on the sub-base or day tank for any site where the generator may sit idle for extended periods. The Fleetguard NanoNet two-stage filter system provides excellent protection, but it must be replaced on schedule; a plugged filter will cause hard starts and power loss under load, which is particularly critical for NFPA 110 Level 1 facilities.
The CM2880 ECM harness connector condition should be inspected at every service interval on outdoor installations. J1939 communication faults can manifest as intermittent shutdowns that are difficult to trace without InPower diagnostic software. We keep an InPower-capable laptop on every C350D6 service call.
Frequently Asked Questions#
What is the difference between the C350 D6 and models in the DQDAB/DQDAC range? The C350D6 uses the QSG12-G1 (11.8L, 6-cylinder) engine. Models in the DQDAA/DQDAB/DQDAC range (250-300 kW) use the QSL9-G7 (8.9L, 6-cylinder) engine. Both engines are inline-6 diesels, but the QSG12 is the larger platform with HPCR injection, while the QSL9 uses a different injection architecture.
What emissions tier is the C350 D6? The C350D6 is EPA Tier 3 certified for stationary emergency standby applications. This is appropriate for most commercial standby installations in the United States. Tier 4 Final compliant options in this power range use different engine variants — consult Cummins for current Tier 4 Final offerings at 350 kW.
What is the fuel consumption at various load points? At 60 Hz standby rating, approximate consumption is 12.2 gph at 50% load, 18.2 gph at 75% load, and 24.6 gph at full standby load. These values are derived from QSG12-G1 engine data and should be verified against the specific C350D6 generator set data sheet (NAD series) for the installed configuration.
What control system does the C350 D6 use? The C350D6 uses Cummins PowerCommand control. The specific control variant (PC 1.1, PC 2.3, or PC 3.3) depends on the configuration — consult the specific model order and data sheet. The engine ECM is the CM2880 with PGI interface and SAE J1939 communications as standard.
What is the lube oil service interval on the QSG12-G1? Cummins rates the QSG12-G1 for 500-hour oil and filter change intervals under standard operating conditions. Oil capacity is 34.1 liters. Lube oil filter is a spin-on full-flow type with a separate StrataPore lube filter element.
FAQ#
What is the standby rating of the Cummins C350 D6?#
The Cummins C350 D6 is rated at 350 kW standby / 438 kVA at 0.8 power factor, 60 Hz, 1800 rpm. Prime rating is 320 kW / 400 kVA. Available in 277/480V and 120/208V three-phase configurations.
What engine does the Cummins C350 D6 use?#
The C350 D6 uses the Cummins QSG12-G1 — an 11.8-liter, inline-6-cylinder, turbocharged and charge-air-cooled diesel with Cummins High Pressure Common Rail (HPCR) fuel injection and the CM2880 ECM. It is EPA Tier 3 certified for stationary emergency standby applications.
What are the service intervals for the Cummins C350 D6?#
Oil and filter changes are due at 500 hours or 12 months, whichever comes first. Air filter and fuel filter replacement are scheduled at 500-hour intervals. Coolant flush is recommended at 4,000 hours. Major overhaul interval is 30,000 hours under standard standby duty conditions, reflecting the larger QSG12 platform's robustness.
Is the Cummins C350 D6 EPA compliant?#
Yes. The C350 D6 is EPA Tier 3 certified for stationary emergency standby applications under 40 CFR Part 60. This is appropriate for large commercial and industrial standby installations throughout the United States.
Can the Cummins C350 D6 be paralleled?#
Yes. The QSG12-G1 engine's PowerCommand control supports paralleling. The specific control variant determines paralleling capability — PowerCommand 2.3 or 3.3 with phase-lock loop synchronizer enables genset-to-genset isochronous load sharing. Consult a Cummins distributor for multi-unit configurations.
What fuel type does the Cummins C350 D6 use?#
The C350 D6 runs on diesel fuel, including ultra-low sulphur diesel (ULSD). The two-stage Fleetguard NanoNet fuel filtration system with a water-in-fuel sensor protects the HPCR injection components. Biodiesel compatibility — confirm blends above B5 with your Cummins distributor for the HPCR system.
What is the warranty on the Cummins C350 D6?#
Standard Cummins warranty is 2 years or 2,000 hours for standby applications. Extended warranty options are available through Cummins authorized dealers.
