Demand Factor for RV Parks
RV parks have a unique electrical load profile because many recreational vehicles may connect to the electrical system at the same time, but they do not all operate their largest loads continuously. Air conditioners, electric water heaters, refrigerators, cooking appliances, battery chargers, and other equipment create a diversified load. This is why the NEC provides specific demand factors for RV park electrical systems.
The demand factor for RV parks helps engineers and electricians calculate a practical feeder load instead of simply adding the full rating of every RV pedestal. Using the correct factor can prevent unnecessary oversizing while still providing adequate capacity for expected usage.
Demand Factor for RV Parks Table
The following values are commonly used with NEC Article 551 calculations for RV site loads. Always confirm the applicable NEC edition and local amendments before final design or installation.
| Number of RV Sites | Demand Factor |
|---|---|
| 1–3 | 100% |
| 4–6 | 75% |
| 7–9 | 65% |
| 10–12 | 60% |
| 13–15 | 55% |
| 16–20 | 50% |
| 21–25 | 45% |
| 26–30 | 40% |
| 31–40 | 35% |
| 41–50 | 30% |
| 51–60 | 27% |
| 61–70 | 25% |
| 71–80 | 23% |
| 81–90 | 22% |
| 91–100 | 21% |
| 101 or more | 20% |
These percentages are applied to the calculated RV site load when determining the calculated feeder demand. They should not be confused with a general diversity factor used for unrelated electrical installations.
For more background on how load diversity is applied across electrical systems, see our guide to diversity factor in electrical installations.
Table of Contents
Table of Contents
What Is the Demand Factor for RV Parks?
The demand factor for RV parks is the percentage of the connected RV load that is expected to be used simultaneously when sizing the electrical supply. For example, a park with 40 RV sites does not necessarily require a feeder sized for the maximum possible load of all 40 sites operating at full capacity.
The basic calculation is:
Calculated Demand Load = Total Connected Load × Demand Factor
Suppose each RV site has a calculated load of 12,000 VA and there are 40 sites.
Total connected load:
40 × 12,000 VA = 480,000 VA
For 31–40 sites, the demand factor is 35%.
Therefore:
480,000 VA × 0.35 = 168,000 VA
The calculated demand is therefore 168 kVA before other applicable loads and requirements are considered.
This approach recognizes the diversity of electrical usage within a large RV campground.
NEC Requirements for RV Park Electrical Loads
RV park electrical design falls primarily under NEC Article 551, Recreational Vehicles and Recreational Vehicle Parks. Section 551.73 addresses the calculation of supply conductors and feeder loads for RV parks.
The actual calculation should account for the type and rating of RV sites, campground equipment, common facilities, and other connected loads. A pedestal serving a 30-amp RV is not treated the same way as one serving a 50-amp RV.
Typical RV site receptacle ratings include:
| RV Service | Voltage | Maximum Apparent Power at Rating |
|---|---|---|
| 30 A, 120 V | 120 V | 3.60 kVA |
| 50 A, 120/240 V | 120/240 V | 12.00 kVA |
| 20 A, 120 V | 120 V | 2.40 kVA |
These figures represent electrical capacity based on voltage and current. The actual calculated load can depend on the specific equipment and NEC requirements applicable to the installation.
How to Calculate an RV Park Electrical Load
A practical calculation can be completed in several steps.
Step 1: Identify the RV Site Ratings
Start by separating the sites according to their service rating. For example, a campground may have 30-amp and 50-amp sites rather than one uniform service.
Step 2: Determine the Calculated Load
Determine the load associated with each site using the applicable NEC requirements. For a simple example, assume 50 sites are each calculated at 12 kVA.
Total connected load:
50 × 12 kVA = 600 kVA
Step 3: Apply the Demand Factor
For 41–50 sites, the table value is 30%.
600 kVA × 0.30 = 180 kVA
The resulting calculated demand is 180 kVA.
Step 4: Add Other Applicable Loads
An RV park may also have loads for:
- Restroom buildings
- Laundry facilities
- Office buildings
- Lighting
- Swimming pools
- Maintenance buildings
- Clubhouses
- Dump stations
- Water pumps
- Security systems
- Electric vehicle charging equipment
These loads should be evaluated separately and included as required by the applicable electrical code.
Example: 100-Site RV Park
Consider an RV campground with 100 identical 50-amp sites. Assume each site has a calculated load of 12 kVA.
Connected load:
100 × 12 kVA = 1,200 kVA
For 91–100 sites, the demand factor is 21%.
Calculated RV demand:
1,200 × 0.21 = 252 kVA
The result is substantially lower than the 1,200 kVA connected rating.
However, 252 kVA should not automatically be treated as the final transformer or service size. Other campground loads, continuous loads, voltage drop, future expansion, equipment ratings, and applicable NEC requirements must also be evaluated.
For a broader explanation of load diversity and how simultaneous demand affects electrical sizing, review our diversity factor in electrical installations guide.
Demand Factor vs. Diversity Factor
These two terms are often used interchangeably in casual electrical discussions, but they describe different concepts.
| Factor | General Meaning | Typical Application |
|---|---|---|
| Demand factor | Maximum demand divided by connected load | Service and feeder calculations |
| Diversity factor | Sum of individual maximum demands divided by system maximum demand | Electrical system planning |
| Load factor | Average load divided by maximum demand | Energy and system utilization studies |
| Utilization factor | Maximum demand relative to equipment capacity | Equipment loading |
For RV campground design, the NEC demand-factor table provides a practical method for accounting for the expected simultaneous use of RV loads.
Understanding these differences is important because applying a generic diversity percentage in place of a code-required demand factor can produce an incorrect result.
Worked Example With Mixed RV Sites
Assume an RV park contains:
- 20 sites with 30-amp service
- 30 sites with 50-amp service
Using the maximum apparent power at the service ratings:
20 × 3.6 kVA = 72 kVA
30 × 12 kVA = 360 kVA
Total connected capacity:
72 + 360 = 432 kVA
There are 50 total RV sites, so the applicable demand factor is 30% under the table shown above.
432 × 0.30 = 129.6 kVA
This gives a calculated RV site demand of approximately 129.6 kVA, before applicable additional loads and design considerations are added.
A qualified designer should verify whether the particular mixture of site ratings requires a more detailed calculation under the adopted NEC edition.
Why Correct Demand Factors Matter
Using a demand factor prevents an RV park electrical system from being designed solely around the theoretical maximum of every receptacle.
This can affect:
- Service size
- Transformer selection
- Feeder capacity
- Distribution equipment
- Conductor sizing
- Voltage-drop calculations
- Generator sizing
- Utility service requirements
- Installation cost
At the same time, demand factors should never be used simply to reduce equipment sizes. The electrical design must still satisfy the NEC, equipment listings, utility requirements, and local regulations.
If you regularly work with electrical load calculations, our diversity factor in electrical installations resource can also help explain how simultaneous loads are evaluated in larger systems.
Important Design Considerations
The demand factor is only one part of an RV park electrical calculation. Designers should also consider the following:
Voltage Drop
Long campground feeders can experience significant voltage drop because RV sites may be spread over a large area. Conductor sizing should consider the actual feeder length, load, conductor material, installation method, and operating voltage.
30-Amp vs. 50-Amp Sites
A 50-amp RV connection can supply considerably more apparent power than a 30-amp, 120-volt connection. Mixing these site types requires careful load calculation rather than simply multiplying the number of spaces by one assumed load.
Continuous Loads
Lighting, equipment, or other loads that qualify as continuous under the applicable NEC requirements may need additional consideration when sizing conductors and overcurrent protection.
Future Expansion
A campground owner may eventually add more RV spaces, EV chargers, laundry equipment, or recreational facilities. Designing only for today’s load can make future expansion expensive.
Common Mistakes in RV Park Load Calculations
Several mistakes can lead to inaccurate electrical sizing:
- Treating every RV pedestal as a continuously loaded circuit.
- Applying a random percentage instead of the applicable NEC table.
- Ignoring the difference between 30-amp and 50-amp RV services.
- Forgetting campground buildings and common-area loads.
- Ignoring voltage drop on long feeder runs.
- Assuming the calculated demand is automatically the final service size.
- Failing to check the NEC edition adopted by the local authority having jurisdiction.
The best approach is to document the connected load, applicable demand factor, additional loads, and final calculated demand before selecting service and distribution equipment.
RV Park Demand Factor Calculator Formula
For a basic calculation, use:
RV Demand = Number of Sites × Calculated Load per Site × Applicable Demand Factor
For mixed site ratings, calculate each applicable load category carefully and follow the requirements of the adopted NEC edition.
For example:
50 sites × 12 kVA × 30% = 180 kVA
This gives a quick estimate of the diversified RV site load.
Remember that a real project may require additional calculations for other campground facilities and electrical equipment.
FAQs
What is the demand factor for RV parks?
The demand factor for RV parks is a percentage used to determine the expected maximum simultaneous RV load. Under the NEC RV park demand-factor table, the percentage decreases as the number of sites increases, recognizing that all RVs are unlikely to operate at maximum demand simultaneously.
What demand factor is used for 50 RV sites?
For 41–50 RV sites, the commonly referenced NEC Table 551.73 demand factor is 30%. The actual calculation should use the applicable NEC edition and account for the specific site ratings and other connected loads.
What is the demand factor for 100 RV sites?
For 91–100 RV sites, the demand factor is 21% under the table shown above. For example, 100 sites with a calculated 12 kVA load each produce 1,200 kVA of connected load, and 21% gives 252 kVA of diversified RV site demand.
Can I use the demand factor to select an RV park transformer?
The calculated demand can be an important input for transformer sizing, but it should not be the only consideration. Other loads, continuous loads, voltage drop, future expansion, transformer loading requirements, utility rules, and applicable NEC provisions must also be evaluated.
Does the RV demand factor include campground buildings?
Not necessarily. RV site demand and other campground facilities should be evaluated according to the applicable NEC requirements. Buildings, pools, laundry rooms, offices, pumps, lighting, EV chargers, and other loads may require separate calculations.
Final Takeaway
The demand factor for RV parks provides a code-based way to account for diversified electrical usage across multiple recreational vehicle sites. As the number of sites increases, the applicable percentage generally decreases, allowing engineers to calculate a more realistic diversified load rather than simply adding every pedestal rating.
For accurate design, start with the RV site ratings, determine the connected load, apply the appropriate NEC demand factor, and then account for additional campground loads and engineering considerations. Always verify the current NEC edition and local amendments before using these values for an actual electrical installation.
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