Quick Hits

⚡ NEC Article 120 — Load Calcs Won't Kill You

🚐 Episode 45 — RV Parks: The Bigger the Park, the Bigger the Discount

Article: 120 — Load Calculations
Part: Part VIII — Recreational Vehicle Parks and Recreational Vehicle Sites
Section: 120.130
Format: Quick Hit

🎯 What You'll Learn

Episode 44 established the baseline VA load for each RV site.

Now we're taking the next step: applying the demand factor from Table 120.130(A) based on the total number of sites in the RV park.

The bigger the park gets, the lower the percentage of each site's calculated load that is included.

📖 The Quick Hit

📉 Table 120.130(A) — RV Site Demand Factors

Once you've determined the baseline load for each site, Table 120.130(A) provides a demand factor based on the total number of RV sites.

Some key points along the curve:

🚐 1 Site

➡️ 100%

🚐 5 Sites

➡️ 65%

🚐 10–12 Sites

➡️ 50%

🚐 19–21 Sites

➡️ 45%

🚐 36 or More Sites

➡️ 41%

That 41% is the floor shown in the table.

🔢 The Important Part: Apply It Uniformly

The demand factor isn't individually assigned to each site based on its particular equipment.

Instead, determine the demand factor from the total number of sites, then apply that same percentage uniformly to each site's calculated load.

Think of the process as:

1️⃣ Determine the VA load for each site

⬇️

2️⃣ Count the total number of sites

⬇️

3️⃣ Find the corresponding demand factor in Table 120.130(A)

⬇️

4️⃣ Apply that percentage to the site loads

⬇️

5️⃣ Add the resulting site loads together

🧮 Worked Example

Suppose an RV park has:

20 sites

and each site has a baseline calculated load of:

3,600 VA

A 20-site park falls within the 19–21 site range.

That gives us a:

➡️ 45% demand factor

Calculate each site's demand load:

3,600 VA × 45% = 1,620 VA

Then multiply by the 20 sites:

1,620 VA × 20 = 32,400 VA

So the calculated demand for the RV sites is:

➡️ 32,400 VA

⚠️ Climate & Additional Loads

The NEC recognizes that demand factors don't necessarily tell the entire story in every location.

In areas with extreme hot or cold climates, substantial heating or air-conditioning loads could make the standard demand factors inappropriate.

Use appropriate judgment when determining whether the calculated demand adequately represents the actual expected load.

🏊 Amenities Are Separate

Things such as:

🏊 Swimming pools

🏢 Recreation buildings

🏚️ Service buildings

and other separately calculated loads aren't simply rolled into the RV-site calculation.

If these loads are supplied by the same service, they are calculated separately and then added to the RV-site load.

🧠 Exam Takeaway

When you see Table 120.130(A), remember:

🚐 Count the total number of RV sites

📊 Find the corresponding demand factor

🔄 Apply that factor uniformly

📉 More sites = lower demand factor

⬇️ 36+ sites → 41%

And don't forget:

Pools, recreation buildings, service buildings, and similar loads are calculated separately.

🎯 Test Yourself

Per Table 120.130(A), what demand factor applies to an RV park with 8 total sites?

A) 65%
B) 60%
C) 55%
D) 50%

✅ Answer

B) 60%

An RV park with 8 total sites falls within the 6–9 site range of Table 120.130(A), which uses a:

60% demand factor

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View Sources & References:
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🔎 NEC References

Primary: Article 120, 120.130(A)

Related: Table 120.130(A) — Recreational Vehicle Site Demand Factors

Related: Part VIII — Recreational Vehicle Parks and Recreational Vehicle Sites

⚡ Series Progress

Article 120 — Load Calcs Won't Kill You

🚐 Part VIII — Recreational Vehicle Parks and Recreational Vehicle Sites

Episode 41: Hospital Receptacles Get Their Own Discount Table
Episode 42: Patient Care Circuits Get Their Own Rule Too
Episode 43: Marinas: Shore Power Gets Its Own Discount Curve
Episode 44: RV Parks: Every Site Gets a Starting Number
Episode 45: RV Parks: The Bigger the Park, the Bigger the Discount

➡️ Next Up

The series continues through Part VIII — Recreational Vehicle Parks and Recreational Vehicle Sites.

Next section: 120.130 and beyond.