What Size Generator Do I Need for a 30 Amp RV?
Published October 20, 2026.
A 30 amp RV is limited by its shore power cord. Match that limit, then check the air conditioner's start.
Full breakdown: RV generator sizing.
As an Amazon Associate I earn from qualifying purchases. The Amazon links below are affiliate links; they don't change the math.
Affiliate disclosure: as an Amazon Associate, we earn from qualifying purchases — at no cost to you.
The numbers
| Figure | Watts | Source |
|---|---|---|
| 30 amp × 120 V shore power | about 3,600 | Cummins |
| Generator that matches shore power | 3,600 | Cummins |
| Generator with extra starting room | 4,000 | Cummins |
| Good minimum for a 30 amp RV with air conditioning | 2,500–2,800 | Cummins |
| 13,500 BTU RV air conditioner, running | 1,800 | Honda |
| 13,500 BTU RV air conditioner, starting | 2,800 | Honda |
| Westinghouse WGen3600, running (TT-30R outlet) | 3,600 | Westinghouse |
| Westinghouse WGen3600, peak | 4,650 | Westinghouse |
How to size it
Start with the cord. Cummins multiplies volts by amps: 120 × 30 is about 3,600 W, the most the coach can draw on a 30 amp hookup. A generator rated 3,600 running watts gives you the same power as the pedestal.
Then check the start. The roof air conditioner is usually the biggest motor. Honda lists a 13,500 BTU unit at 2,800 W to start and 1,800 W to run. A 15,000 BTU unit is larger; see the 15,000 BTU RV air conditioner page, and the single-unit detail is on the 13,500 BTU page.
Add the other loads that run with it, then size from the total. Running wattages for common appliances are in the portable generator watts chart, and the generator size calculator adds them for you.
Look for a TT-30R outlet so the RV cord plugs straight in. The WGen3600 is one listed example. For tent or van trips with no air conditioner, see the best portable generator for camping.
FAQ
Why 3,600 watts for a 30 amp RV?
Watts are volts times amps. Cummins uses 120 V × 30 A, which is about 3,600 W, the most a 30 amp shore connection can carry.
Is 4,000 watts better than 3,600?
Cummins says a 4,000 W generator gives additional motor-starting power. That matters most when the roof air conditioner starts.
What is the smallest generator that can run the air conditioner?
Cummins calls 2,500 to 2,800 W a good minimum for 30 amp RVs with air conditioning. Honda lists a 13,500 BTU RV air conditioner at 2,800 starting watts.
What plug does a 30 amp RV use?
A TT-30 plug. The Westinghouse WGen3600 is one example with a TT-30R outlet on the panel.
Related questions
- What size generator for an RV
- What size generator for a 13,500 BTU RV air conditioner
- What size generator for a 15,000 BTU RV air conditioner
All of these questions are listed on the topic map.
Compiled with AI assistance from the sources below. Spot an error? Email [email protected].