Overview#
The Cummins C80 N6 is an 80 kW standby natural gas generator set sold as part of the Quiet Connect RS80 series. It is built on the QSJ5.9G spark-ignited engine -- a 5.9-liter, inline-6-cylinder, turbocharged and aftercooled platform that Cummins also uses in the C100 N6. The C80 N6 ships standard in a sound-attenuated aluminum enclosure rated at 73 dB(A) at 23 ft, making it one of the quieter options in its class for suburban commercial and light-industrial installations.
The generator is certified to EPA Stationary Emergency standards (40 CFR 60), listed to UL 2200, and is NFPA 110 capable when properly installed with the required accessories. It accepts single-step load pickup per NFPA 110 requirements. The PowerCommand 1.1 control provides isochronous governing, automatic remote start/stop, output metering, and self-diagnostics. The enclosure is wind-rated to 180 mph per ASCE 7-10 and carries IBC Seismic certification.
The C80 N6 targets smaller commercial installations -- professional office buildings, small medical clinics, restaurant facilities, and light-industrial buildings -- where 80 kW of standby capacity is sufficient and acoustic performance is important. It is frequently specified alongside a Cummins RA or RSS automatic transfer switch.
Technical Specifications#
| Parameter | Value |
|---|---|
| Standby Rating | 80 kW (100 kVA) |
| Frequency | 60 Hz |
| Engine Model | QSJ5.9G |
| Displacement | 5.9 liters (359 in³) |
| Configuration | Inline 6, cast iron block |
| Aspiration | Turbocharged and aftercooled |
| Bore x Stroke | 102.1 mm x 119.9 mm (4.02 x 4.72 in) |
| Rated Speed | 1800 rpm |
| Overspeed Limit | 2250 rpm |
| Starting System | 12 VDC, 850 CCA battery |
| Battery Charging Alternator | 52 amps |
| Lube Oil Filter | Spin-on with relief valve |
| Cooling | Set-mounted radiator, 50 C ambient design |
| Control | PowerCommand 1.1 |
| Enclosure | Aluminum, Sound Level 1 |
| Open Set Weight (wet) | 1,173 kg (2,587 lbs) |
| SL1 Enclosure Weight (wet) | 1,262 kg (2,782 lbs) |
| Dimensions (L x W x H) | 118.7 x 40.0 x 58.3 in (3016 x 1016 x 1480 mm) |
| Sound Level | 73 dB(A) at 23 ft with SL1 enclosure |
Natural gas fuel consumption (CFH at 905 Btu/ft³):
| Load | CFH |
|---|---|
| 25% | 455 |
| 50% | 679 |
| 75% | 877 |
| 100% | 1,084 |
Fuel inlet pressure: 6.0 to 14.0 in WC (1.5 to 3.5 kPa) at the engine connection.
Available voltage configurations:
- 1-phase: 120/240V
- 3-phase: 120/208V, 120/240V, 277/480V
Our Service Experience#
The C80 N6 is a straightforward unit to maintain. The QSJ5.9G engine shares its basic architecture with Cummins' broader B/QSB diesel family adapted for gas, meaning parts availability is strong and technicians familiar with Cummins gas engines adapt quickly. The 12V single-battery starting system is simpler than the 24V systems on larger units, but battery condition is still the most common cause of fail-to-start events -- we recommend annual battery load testing and replacement every 3-4 years in commercial standby service.
The sound-attenuated aluminum enclosure does a good job at 73 dB(A), but the intake and exhaust baffles require periodic inspection to confirm no debris accumulation. The aluminum construction resists corrosion well, which matters in coastal installations. Fuel inlet pressure must be verified in the 6-14 in WC range under operating load -- we have seen units at the edge of this range develop fuel-lean conditions under high ambient temperatures that affect transient response.
Frequently Asked Questions#
What is the standby power rating of the C80 N6? 80 kW (100 kVA) at 60 Hz, 0.8 power factor, tested per NFPA 110. This rating applies for the duration of a utility power interruption with no sustained overload capability.
What engine does the C80 N6 use? The Cummins QSJ5.9G -- a 5.9-liter, inline-6, turbocharged and aftercooled spark-ignited natural gas engine. The same engine platform (at a higher power rating) powers the C100 N6. It operates at 1800 rpm with an overspeed limit of 2250 rpm.
What voltages does the C80 N6 support? Single-phase 120/240V and three-phase 120/208V, 120/240V, and 277/480V. The alternator is 12-lead reconnectable for field voltage adjustment.
How much natural gas does the C80 N6 consume at full load? Approximately 1,084 CFH (standard cubic feet per hour) at 100% load, based on 905 Btu/ft³ gas. At 75% load the consumption drops to 877 CFH, and at 50% load to 679 CFH.
Is the C80 N6 compliant with NFPA 110? The C80 N6 is NFPA 110 capable when equipped with the necessary accessories and properly installed. The PowerCommand 1.1 control supports Level 1 compliance. Confirm with your installing contractor that all required accessories (coolant heater, battery charger, transfer switch) are properly specified.
What enclosure does the C80 N6 come with? The standard Quiet Connect RS80 enclosure is an aluminum Sound Level 1 enclosure rated at 73 dB(A) at 23 ft. An upgrade to Sound Level 2 is available as an accessory kit. The enclosure is wind-rated to 180 mph per ASCE 7-10 and carries IBC Seismic certification.
