Cummins 125kW QuietConnect Diesel Home Standby Generator — C125D6
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At a glance
- Standby Rating
- 125 kW (156 kVA); 112.5 kW Prime
- Voltage/Phase
- 1-Phase 120/240V; 3-Phase 120/208V, 277/480V, 347/600V, 127/220V (60 Hz)
- Fuel
- Diesel
- Engine
- Cummins QSB5-G6, 4-cylinder cast-iron in-line, turbocharged & charge-air cooled, 1800 rpm
- Cooling
- Liquid-cooled (set-mounted radiator)
- Emissions
- EPA Tier 3, Stationary Emergency
- Sound Level
- 71.3 dBA at 23 ft (7 m) with Level 2 enclosure
- Fuel Consumption (full standby)
- 10.3 US gph (38.99 L/hr)
- Weight
- 2,586 lbs (1,173 kg) open genset, wet
- Warranty
- 2-year / 1000-hour limited warranty
Why this generator
- Delivers 125 kW (156 kVA) of standby power from a Cummins QSB5-G6 turbocharged 4-cylinder diesel engine running at 1800 rpm
- Liquid-cooled design with a set-mounted radiator rated for 40C (104F) ambient operation for sustained heavy-load duty
- Flexible voltage configurations including 1-phase 120/240V and multiple 3-phase options (up to 347/600V) for residential, commercial, and agricultural sites
- EPA Tier 3 stationary-emergency certified for compliant backup power
- Available with a CPG sound-attenuating Level 2 enclosure measured at 71.3 dBA at 23 ft for quieter operation
- Backed by a Cummins 2-year / 1000-hour limited warranty
Everything you need to know
The Cummins C125D6 is a 125 kW diesel standby generator from the Cummins QuietConnect commercial-grade series — a liquid-cooled machine built to carry commercial buildings, agricultural and industrial sites, and multi-building properties through extended utility outages. With an energy-dense on-site fuel supply, it delivers full rated output and complete fuel autonomy, independent of the utility gas grid.
Automatic, Hands-Off Backup
Paired with a Cummins automatic transfer switch, the C125D6 monitors utility power continuously, starts within seconds of an outage, and transfers the full load automatically — then returns to utility power and shuts down once the grid is restored. No manual switching, no cords, and no downtime for the systems that can't go dark.
Commercial-Grade Power & Control
Cummins PowerCommand control governs the C125D6 with precise voltage and frequency regulation and strong motor-starting capability — critical for hard-starting loads like central air conditioning, well and irrigation pumps, refrigeration, and three-phase equipment. It's the same power pedigree Cummins builds for hospitals, data centers, and critical facilities, scaled for commercial and industrial use.
Diesel Power & Fuel Autonomy
Diesel makes the C125D6 the right choice where natural gas isn't available, or where you want full control of your own fuel supply. Diesel's energy density delivers strong full-load performance, and an on-site tank keeps you running through extended outages on your own schedule.
Factory-Authorized, Quote-Based Pricing
Total Generator Pros is a factory-authorized Cummins dealer. Because every large-format standby installation is engineered to the site, pricing on the C125D6 is quote-based. Request a free quote and we'll spec the unit, transfer switch, and installation for your project — with free nationwide shipping, turnkey installation across North & South Carolina, and 0% APR financing available on qualifying orders.
- 125 kW standby power
- Cummins QuietConnect series, liquid-cooled
- Diesel fuel
- Cummins PowerCommand digital control
- Automatic whole-building transfer with a Cummins ATS
- Commercial-grade, engineered for commercial and industrial use
- Model C125D6
Frequently asked questions
What fuel does the C125D6 run on?+
The C125D6 is a diesel-powered standby generator.
Does the price include installation?+
No — the online price covers the unit shipped free to the lower 48. Professional installation is available in NC & SC on a quote basis; outside that area we'll help you find a qualified local installer.
How fast does it ship?+
Free curbside / liftgate shipping to the contiguous 48 states. Made-to-order units typically ship in 12 weeks or less.
What warranty is included?+
5-year limited factory warranty, registered and supported directly through Cummins.
Is financing available?+
Yes — 0% APR financing is available on qualifying orders. Ask us for details before checkout.
Free curbside shipping
Liftgate delivery to the lower 48. Ships in 12 weeks or less (made-to-order commercial unit).
Install help, no upsell
We size, spec, and connect you with a vetted local installer — or talk your contractor through it for free.
Real Cummins warranty
Full 5-year limited warranty — registered and supported through Cummins directly.