Cummins RS100
Liquid-cooled · Natural Gas / LP Vapor
Equipment from
$39,905.52
Equipment only. Installation quoted after a free site survey.
View detailsConnect Series Liquid-Cooled
Cummins RS125
125kW liquid-cooled standby generator, Natural Gas / LP Vapor. Clinics, restaurants, data closets, cold storage, multi-tenant retail and small industrial.
Representative manufacturer image of the range. Enclosure finish, color and dimensions vary by model and configuration — see the specifications below for this unit.
125 kW Natural Gas / LP Vapor Liquid-cooled Aluminum
The RS125 is liquid-cooled. That matters above roughly 25kW, where an air-cooled engine can no longer shed heat during the long runs a multi-day outage demands. It is a larger machine - 143 x 40 x 72 inches and 3915 lb - and it needs a proper pad and clearance.
It runs on natural gas or LP vapor. On natural gas there is no tank to fill and no runtime limit as long as the utility main holds pressure, which is why it is the default choice on almost every DFW home that already has gas service.
Available in 4 factory configurations: 120/208 3Ph, 277/480 3Ph, 120/240 3Ph, 120/240 1Ph. The correct one depends on your incoming service, not on preference - ordering the wrong voltage is the single most expensive mistake on a job like this, so we confirm it against your meter and panel before anything is ordered.
Pricing
Quoted per project
Units at this size are specified against your electrical service, switchgear and fuel arrangement, so they are quoted per project rather than listed at a shelf price.
- ✓ Concrete or composite pad
- ✓ Gas line sizing and pressure test
- ✓ Transfer switch and electrical tie-in
- ✓ Permit and city inspection
- ✓ Startup, load test and walkthrough
The five items above are part of the installation quote, not the equipment price.
Reserve this unit — (214) 957-4307Refundable deposit · locks this price 90 days · schedules your free survey · applies 100% to final invoice
Get a free quote firstNot ready to reserve? Have us call you.
Got it. We will call you. If you would rather not wait, ring (214) 957-4307 and ask for whoever is on generators.
Specifications
| Model | Cummins RS125 |
|---|---|
| Rated output | 125 kW |
| Fuel | Natural Gas / LP Vapor |
| Cooling | Liquid-cooled |
| Enclosure | Aluminum |
| Weight | 3915 lb |
| Dimensions (L×W×H) | 143 x 40 x 72 in |
| Voltage configurations | 120/208 3Ph, 277/480 3Ph, 120/240 3Ph, 120/240 1Ph |
| Extreme cold package | Available as an upgrade |
| Transfer switch | Sold separately, sized to your service |
| Application | commercial |
| Rated amps (NG / LP) | 520.8 / 520.8 A at 120/240 V |
| Sound level | 73 dB(A) at 23 ft (7 m) with Sound Level 2 enclosure |
| Cummins model | C125 N6 |
| Displacement | 8.9 liters (543 in³) |
| Cylinder block | Cast iron, in-line 6 cylinder |
| Rated speed | 1800 rpm |
| Voltage regulation | ±1.0% no load to full load |
| Frequency regulation | ±0.75% random at 60 Hz |
| Governor class | ISO 8528 Part 1 Class G2 |
| Controller | PowerCommand electronic control |
| Main breaker | 600 A |
| Derating | Full engine power to 2,500 ft at up to 104°F. Above that, derate 4% per 1,000 ft and 2% per 10°C. |
| Fuel | Natural gas and LP output are identical on the liquid-cooled range — there is no natural gas derate. |
| Certifications | UL 2200 |
| Warranty | 2 year standby base warranty. Extended warranty options available. |
Available configurations
4 factory configurations. We confirm the correct one against your service before anything is ordered.
| Part number | Voltage | Phase | Price |
|---|---|---|---|
| A063A442 | 120/208 | 3Ph | — |
| A063A449 | 277/480 | 3Ph | — |
| A063A453 | 120/240 | 3Ph | — |
| A063B604 | 120/240 | 1Ph | — |
This model is quoted directly rather than listed. Part numbers are shown so you can confirm exactly what you are being quoted.
Built in
What the RS125 does that the spec table does not show
1800 rpm, not 3600
Liquid-cooled sets turn at half the speed of an air-cooled unit. Fewer revolutions per hour of running means less wear, and it is a large part of why these are quieter despite being far more powerful.
Sound Level 2 enclosure
From 60 dB(A) at 23 feet on the smaller sets. A 30kW liquid-cooled unit is quieter than a 20kW air-cooled one.
PowerCommand control
Electronic governing and voltage regulation, with alarm and status monitoring. Regulation is tighter than the air-cooled range at ±1.0%.
Continuous rated output
A radiator loop means it can hold rated output indefinitely rather than shedding heat into the air. That is the practical difference in a multi-day outage.
Accessories and maintenance parts for this unit →
Specifications on this page are taken from the Cummins published specification sheet for
the air-cooled Connect range.
Download it from Cummins →
Pairs with
Transfer switches for a 125kW set
The switch is sized to your electrical service, not to the generator. These are the families that typically apply at this output — we confirm the exact one at the survey.
Questions about the RS125
How much does a Cummins RS125 cost installed in Dallas-Fort Worth?
The RS125 is quoted per project rather than listed at a shelf price. Units at this size are specified against your electrical service, switchgear and fuel arrangement, so a shelf number would be meaningless. Tell us the application and we will put equipment and installation in writing together.
What will the RS125 actually run?
Commercial standby power for facilities with substantial motor and HVAC load. Final confirmation comes from a load calculation against your actual panel, which we do at the survey.
Do I need a transfer switch with the RS125?
Yes. A standby generator cannot be code-compliantly connected without an automatic transfer switch - it is what keeps your generator from backfeeding the utility line and endangering line crews. The switch is sized to your electrical service, not to the generator, so we confirm your service size at the survey before specifying it.
Is the RS125 in stock?
Availability changes weekly. A refundable deposit reserves a specific unit and locks the equipment price for 90 days, which is the practical way to hold one while the survey and permit work happen. If we cannot source it in a reasonable window, you get the deposit back.
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View detailsWant the RS125 priced for your address?
This model is quoted directly. Tell us the application and we will put equipment and installation in writing together.