Connect Series Liquid-Cooled

Cummins RS40

40kW liquid-cooled standby generator, Natural Gas / LP Vapor. Estate properties and small commercial buildings that cannot afford a dark day.

Representative manufacturer image of the range. Enclosure finish, color and dimensions vary by model and configuration — see the specifications below for this unit.

40 kW Natural Gas / LP Vapor Liquid-cooled Aluminum

The RS40 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 - 94 x 34 x 45.5 inches and 1356 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: 120/240 1Ph, 120/208 3Ph, 120/240 3Ph, 277/480 3Ph. 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.

Equipment price

$18,910.82

Equipment only — installation quoted separately

✓ 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) 957-4307

Refundable deposit · locks this price 90 days · schedules your free survey · applies 100% to final invoice

Get a free quote first

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Specifications

Model	Cummins RS40
Rated output	40 kW
Fuel	Natural Gas / LP Vapor
Cooling	Liquid-cooled
Enclosure	Aluminum
Weight	1356 lb
Dimensions (L×W×H)	94 x 34 x 45.5 in
Voltage configurations	120/240 1Ph, 120/208 3Ph, 120/240 3Ph, 277/480 3Ph
Extreme cold package	Available as an upgrade
Transfer switch	Sold separately, sized to your service
Application	light commercial
Rated amps (NG / LP)	166.7 / 166.7 A at 120/240 V
Sound level	63 dB(A) at 23 ft (7 m) with Sound Level 2 enclosure
Cummins model	C40 N6
Displacement	2.4 liters (143.5 in³)
Cylinder block	Cast iron, in-line 4 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	200 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
A051Y419	120/240	1Ph	$18,910.82
A051Y420	120/208	3Ph	$18,910.82
A051Y421	120/240	3Ph	$18,910.82
A051Y424	277/480	3Ph	$18,910.82

All prices are for the equipment only.

Built in

What the RS40 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 40kW 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.

RA 200A

Service-entrance rated options available. 3 configurations.

From

$976.38

RSS200 200A

1 configurations.

From

$1,373.94

Questions about the RS40

How much does a Cummins RS40 cost installed in Dallas-Fort Worth?

The RS40 equipment price is $18,910.82. Installation on a 40kW liquid-cooled unit varies too widely to band honestly - the pad, the fuel supply, the switchgear and the electrical service are all engineered to the specific site. We quote it in writing after a site survey, and we will tell you the drivers before we quote so you can see where the money goes.

What will the RS40 actually run?

Estate homes, or light commercial loads such as a small clinic, restaurant, retail suite or office. 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 RS40?

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 RS40 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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