Service parts for the C300N6
Grouped by system, with how many of each the parts manual calls for.
Fuel system
1 requiredPrices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.
Specifications
| Fuel | Natural gas |
|---|---|
| Frequency | 60.0 Hz |
| Standby power | 300 kW |
| Standby kVA | 375 |
| Controller | PowerCommand 3.3 MLD |
| Oil capacity | 34.0 L |
| Alternator | S4L1D-D41 (4-pole, Class Class H insulation) |
| Voltage options | 277/480 V |
| Phase | 3 |
| Rated current | 451 A |
| Power factor | 0.8 |
| Circuit breaker | 600 A |
| Battery cranking | 900 CCA |
| Battery voltage | 24 V |
| Coolant capacity | 136 L |
| Max ambient | 40 °C |
| Sound level | 73.4 dBA @ 7 m |
Engine
| Oil capacity | 34.0 L |
|---|---|
| Coolant capacity | 136.0 L |
| Displacement | 14.0 L |
| Aspiration | Turbocharged and coolant-air aftercooled |
| Rated speed | 1800 rpm |
Maintenance & consumables
for the Cummins/Onan GTA855E| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | — | ||||
| Fuel filter | 149-0751 | Amazon eBay | |||
| Oil filter | — | ||||
| Battery | — | ||||
| Belt | — | ||||
| Coolant | 136.0 | — | |||
| Oil | 34.0 | — | |||
| Spark plug | — |
Service specifications
18| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Other | BMEP at set rated load | 243 | psi | |
| Other | Compression ratio | 8.5:1 | ||
| Other | Maximum speed | 2250 | rpm | |
| Other | Piston speed | 1795 | ft./min | |
| Pressure | Catalyst back pressure | 20.4 | in. H2O | |
| Pressure | Fuel inlet pressure maximum operating | 20 | in. H2O | |
| Pressure | Fuel inlet pressure minimum operating | 14 | in. H2O | |
| Pressure | Max air cleaner restriction (dirty filter) | 15 | in. H2O | |
| Pressure | Max allowable system back pressure | 47.7 | in. H2O | |
| Pressure | Max cooling air flow static restriction | 0.5 | in. H2O | |
| Resistance | Rotor resistance | 1.05 | Ohms | @ 22°C |
| Resistance | Stator resistance (L-L) | 0.0248 | Ohms | @ 22°C |
| Speed | Overspeed limit | 2100 | rpm | |
| Temperature | Ambient design | 104 | °F | |
| Temperature | Exhaust temp | 1146 | °F | |
| Torque | Tightening torque (circuit breaker lug) | 442.54 | Lbf.In | AWG 3/0...500 kcmil |
| Voltage | Excitation current full load | 2.3 – 2.2 | Amps | full load |
| Voltage | Excitation current no load | 0.7 – 0.5 | Amps | no load |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Recommended fluids
| Fluid | Grade | Standard | Ambient | Capacity | Notes |
|---|---|---|---|---|---|
| Coolant | 50/50 Mix | 136.0 L | System filled prior to shipment; Anti-Freeze 50/50 mix | ||
| Fuel | Natural gas | Fuel consumption at 100% load: 4098 SCFH; Required operating fuel pressure: 14-20 in H2O |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Procedures
2Switch Adjustment adjustment
Tools: wire seal MICROTUSEAL
- Open switch cover (A).
- Adjust the appropriate switches (B) to desired values.
- Replace switch cover. Use wire seal MICROTUSEAL (C), if necessary, to provide tamper evidence.
Trip Unit Operation Verification diagnostic
Tools: test kit
- Set pickup levels.
- Set time delay.
- Use a test kit connected to the trip unit test plug receptacle (A) to verify trip unit is functioning as desired.
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Voltage reconnection
| Voltage | Phase | Connection | Leads | Notes |
|---|---|---|---|---|
| 208/416 | 3 | 12 | winding 311 | |
| 220/440 | 3 | 12 | winding 311 | |
| 230/460 | 3 | 12 | winding 311 | |
| 240 Delta | 3 | 12 | winding 311 | |
| 240/480 | 3 | 12 | winding 311 | |
| 277/480 | 3 | 12 | genset rated voltage, 3ph |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Common questions
What size generator is the Cummins/Onan C300N6?
The Cummins/Onan C300N6 is rated 300 kW standby (375.0 kVA).
Which engine powers the Cummins/Onan C300N6?
The Cummins/Onan C300N6 is powered by the Cummins/Onan GTA855E engine.
What kind of fuel does the Cummins/Onan C300N6 run on?
The Cummins/Onan C300N6 runs on Natural gas.
What's the oil capacity on a Cummins/Onan C300N6?
The Cummins/Onan GTA855E engine in the Cummins/Onan C300N6 has an oil capacity of 34.0 liters.
What is the coolant capacity of the Cummins/Onan C300N6?
The Cummins/Onan C300N6 cooling system holds 136 liters (35.9 US gallons) for the radiator system including the engine, per the manufacturer specification sheet.
How loud is the Cummins/Onan C300N6?
The Cummins/Onan C300N6 is rated at 73.4 dBA at 7 m, per the manufacturer specification sheet.
What voltages is the Cummins/Onan C300N6 available in?
The Cummins/Onan C300N6 is offered in 277/480 V, 3-phase.
What battery does the Cummins/Onan C300N6 use?
The Cummins/Onan C300N6 uses 24 V each, 900 CCA, per the manufacturer specification sheet.
Which alternator is fitted to the Cummins/Onan C300N6?
The Cummins/Onan C300N6 uses a S4L1D-D41 alternator. It has 4 poles. Insulation class Class H.
What fuel filter fits the Cummins/Onan C300N6?
The Cummins/Onan C300N6 uses fuel filter part number 149-0751.
Troubleshooting
5Symptoms & remedies
| Symptom | Remedy |
|---|---|
| Battle short mode | If enabled and the battle short switch is active, some shutdown faults will be bypassed. However, emergency stop shutdowns and other critical operations are not bypassed. |
| Derate | The Derate function reduces output power of the genset in response to a fault condition. In utility parallel mode, it actively reduces power by lowering the base load kW to the derated target kW. |
| Configurable alarm and status inputs | The control accepts up to four alarm or status inputs (configurable contact closed to ground or open) to indicate a configurable condition. The control is programmable for warning, derate, shutdown, shutdown with cooldown or status indication and for labeling the input. |
| Emergency stop | Annunciated whenever either emergency stop signal is received from an external switch. |
| General prime mover protection | Low and high battery voltage warning - Indicates status of the battery charging system (failure) by continuously monitoring battery voltage. Weak battery warning - The control system will test the battery each time the genset is signaled to start and indicate a warning if the battery indicates impending failure. Low coolant level warning – Can be set up to be a warning or |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Parts
8| Part # | Description | Qty | System | |
|---|---|---|---|---|
| 0307-3047 | Relay (24V) | Relay 24v | Amazon eBay | |
| 0332-3923-02 | Terminal Block | 3 | Terminal block | Amazon eBay |
| 0332-3925-02 | Jumper-Terminal | Jumper terminal | Amazon eBay | |
| 0332-3943-02 | Jumper-Terminal | Jumper terminal | Amazon eBay | |
| 0332-4036-02 | Terminal Block (Earth) | Terminal block | Amazon eBay | |
| 0249-0814 | Relay 2P Base | 1 | Service part / kit | Amazon eBay |
| 0332-3926 | Terminal Block (End Stop) | 2 | Service part / kit | Amazon eBay |
| 0332-3927-02 | Terminal Block (End Plate) | 1 | Service part / kit | Amazon eBay |
Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.
Available documents
This page was generated from the 2 manufacturer documents above by automated extraction; every figure shown is copied from one of them. How the data is compiled.