Reference
RV Shore Power Ratings Chart: 15A, 20A, 30A and 50A Service
Researched from published standards and manufacturer specifications. Updated .
Quick answer
A 30A RV service is one 120V leg at 30A, 3,600 VA total. A 50A RV service is two separate 120V legs at 50A each, 12,000 VA total, more than three times the power of 30A, not a modest 67 percent increase the amp numbers alone suggest. An adapter changes the plug shape only and never increases the amperage available: a 50A rig plugged into a 30A pedestal through a dogbone is still limited to 30A and 3,600 VA total.
RV shore power ratings look like a simple ladder of amp numbers, 15, 20, 30, 50, but the jump from 30A to 50A is not a linear step. A 50A service is split-phase, two independent 120V legs, which is why it delivers more than three times the total power of 30A rather than a proportional 67 percent more.
This chart lines up every service an RV owner actually plugs into, shows the safe continuous draw at each one, and walks through exactly what a dogbone adapter changes and what it cannot.
What is RV shore power, and why isn't 50A just more than 30A?
Shore power is the AC connection between an RV and an external power source, most often a campground pedestal, delivered through one of a small number of standardized NEMA plug configurations. The critical detail that trips up the amp-number comparison is that a 30A service is single phase, one 120V leg, while a 50A service is split phase, two separate and independently usable 120V legs. That structural difference, not just a bigger number, is why 50A service delivers more than three times the total power of 30A rather than a proportionally modest increase.
Shore power and household service ratings, side by side
| Service | Device | Legs | Volts per leg | Amps per leg | Total VA capacity |
|---|---|---|---|---|---|
| 30A RV service | NEMA TT-30 | 1 | 120 | 30 | 3600 |
| 50A RV service | NEMA 14-50 | 2 | 120 | 50 | 12000 |
| 20A household outlet | NEMA 5-20 | 1 | 120 | 20 | 2400 |
| 15A household outlet | NEMA 5-15 | 1 | 120 | 15 | 1800 |
Published standard Source: NEMA device configurations and NFPA 1192, Standard on Recreational Vehicles, for RV park supply. 50A total VA capacity comes from two independent 120V legs at 50A each, not a single 240V circuit the way a household 240V appliance circuit works.
Continuous-load safe draw at each service
NEC 210.19(A) and 210.20(A) work together as one rule: a continuous load, one expected to run three hours or more, should not exceed 80 percent of the breaker rating, the inverse of the 125 percent sizing factor used when picking an overcurrent device for a known load.
| Service | Total VA capacity | Continuous-safe VA (80%) |
|---|---|---|
| 30A RV service | 3600 | 2880 |
| 50A RV service | 12000 | 9600 |
| 20A household outlet | 2400 | 1920 |
| 15A household outlet | 1800 | 1440 |
Published standard Source: NEC 210.19(A) and 210.20(A), continuous loads limited to 80 percent of breaker rating. This is a planning ceiling for loads running three hours or more, such as an air conditioner on a hot afternoon; brief loads like a hair dryer or a kettle are not held to the 80 percent figure.
What an adapter actually changes, and what it never can
An adapter, sometimes called a dogbone, changes the plug shape so a cord can physically connect to a different receptacle. It never changes the amperage the source circuit at the pedestal, or the rig’s own wiring, can actually deliver, whichever of the two is lower.
| Scenario | Adapter used | Actual amps available | Actual VA available |
|---|---|---|---|
| 50A rig plugged into a 30A pedestal | 50-to-30 dogbone | 30A, one 120V leg only | 3,600 VA, not 12,000 |
| 30A rig plugged into a 50A pedestal | 30-to-50 dogbone | 30A, one leg of the 50A pair | 3,600 VA |
| 30A rig plugged into a 20A household outlet | Household plug adapter | 20A | 2,400 VA |
| 30A rig plugged into a 15A household outlet | Household plug adapter | 15A | 1,800 VA |
Published standard Source: NEMA device ratings; an adapter changes plug shape only and can never exceed the amperage of the source circuit or the rig’s own wiring, whichever is lower. A 50A rig on a 30A pedestal cannot run both air conditioners at once no matter what adapter is used, because the pedestal itself only supplies 30A of one leg.
Why a surge protector needs to match the service, not just the plug
A 30A EMS and a 50A EMS both plug into their matching service, but they are not interchangeable beyond the physical connector. A 50A service is two independent 120V legs, so a proper 50A EMS monitors each leg separately for voltage, frequency and wiring faults, since a problem on one leg alone, like an open neutral or a reversed leg, would not necessarily trip protection built for a single 120V circuit. Using a 30A-rated protector behind a 50A-to-30A dogbone is fine for what it is, protecting the single 30A leg actually in use, but it is not equivalent to full 50A split-phase protection once the rig is connected natively to a 50A pedestal.
What actually fits on a 30A service versus a 50A service
A single 13,500 BTU air conditioter at roughly 1,400 running watts leaves meaningful headroom under a 30A service’s 2,880 VA continuous-safe figure for a few smaller loads at once, but a second air conditioner, an electric water heater and a hair dryer running together will push well past it. A 50A service, with two independent 120V legs each rated near 4,800 VA continuous-safe, is built for running two air conditioners plus a full kitchen load simultaneously, which is exactly the gap the total VA numbers above show between the two services.
Cords, adapters and surge protection for each service
Buy the cord and adapter rated for the service actually available at the pedestal, and buy the EMS sized to the higher-power service being protected, since it needs to survive whatever surge or miswire event it is designed to catch.
Progressive Industries EMS-PT30X, 30A
$135.89Surge and miswire protection matched to the single 120V leg a 30A pedestal supplies.
Best for: Anyone plugging into parks they have not vetted.
Check price on Amazon
Progressive Industries EMS-PT50X, 50A
$187.15Monitors both 120V legs independently on a split-phase 50A service.
Best for: Any 50A rig.
Check price on Amazon
Cable Matters 30A 25ft RV Power Cord
$54.99A 25 foot cord matched to the TT-30 device rating in the table below.
Best for: Replacing a damaged original cord.
Check price on Amazon
ELEGRP 30A to 50A Dogbone Adapter
$19.19Lets a 30A rig plug into a 50A pedestal without changing the 30A ceiling explained in the adapter table below.
Best for: A 50A rig at a 30A pedestal, with loads managed accordingly.
Check price on AmazonFrequently asked questions
- Does a 50A-to-30A adapter let a rig draw 50A from a 30A pedestal?
- No. The adapter only changes the plug shape so the cord can connect; the pedestal circuit behind a 30A receptacle still only supplies 30A on a single 120V leg, 3,600 VA total, regardless of what plugs into it. A 50A rig on that adapter is limited to 30A no differently than a native 30A rig would be.
- Why is 50A service more than three times the power of 30A, not just 67 percent more?
- 30A service is single phase, one 120V leg. 50A service is split phase, two independent 120V legs at 50A each. Comparing total VA capacity, 3,600 for 30A versus 12,000 for 50A, shows the real jump is more than three times, because the structural change from one leg to two legs matters more than the amp number alone suggests.
- What is a dogbone adapter and what does it not do?
- A dogbone adapter is a short cord with two different plug ends that lets an RV cord physically connect to a receptacle of a different rating, such as a 50A rig plugging into a 30A pedestal. It changes only the physical connection; it never increases the amperage or total power the source circuit can actually deliver.
- How much continuous load can a 30A pedestal actually carry?
- Applying the NEC 80 percent continuous-load rule to a 30A service’s 3,600 VA total gives 2,880 VA as the safe figure for loads expected to run three hours or more, such as an air conditioner on a hot afternoon. Brief loads are not held to that lower figure, but stacking several continuous loads past 2,880 VA risks tripping the pedestal breaker.
- What is the difference between a 20A household outlet and 30A RV service?
- Both are single 120V legs, but a 20A household outlet, NEMA 5-20, supplies 2,400 VA total versus 3,600 VA for a 30A RV service, NEMA TT-30. An RV plugged into a household outlet through an adapter is limited to the lower 20A rating and its narrower continuous-safe draw of 1,920 VA.
- Do I need an EMS surge protector at every service size?
- A surge and miswire protector, an EMS, is worth using at any service size, since pedestal wiring faults and surges occur at 15A and 20A outlets as well as at 30A and 50A. The unit should be rated for the amperage of the service it protects; a 50A EMS on a 50A service needs to monitor both 120V legs independently rather than treating it as a single higher-amp circuit.
An adapter is a plug shape, not a power upgrade. Whatever service a pedestal actually supplies, 15A, 20A, 30A or 50A, is the real ceiling regardless of what cord or dogbone connects to it. Budget the load against the total VA and the 80 percent continuous-safe figure for the pedestal’s actual rating, not the rig’s own shore power inlet rating.