Solved NEC Standard Electrical Load Calculation for Single | Chegg.com - Free Printable

Let’s go step by step to fill out this NEC Standard Electrical Load Calculation form. We’ll assume some typical values since the owner, location, and floor area aren’t given — but we can still show you how to do it correctly.

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Step 1: General Lighting (Line 1)
NEC says: 3 VA per square foot for general lighting.
Let’s say the house is 2,000 sq.ft. (a common size).
So: 2,000 × 3 = 6,000 VA

→ Line 1: Quantity = 2000 sq.ft., Volt Amperes = 6000

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Step 2: Small Appliance Circuits (Line 2)
NEC requires at least 2 circuits, each 1500 VA.
So: 2 × 1500 = 3,000 VA

→ Line 2: Quantity = 1500 X 2 → but form says “1500 X” so we write 3000 in VA column? Wait — actually, the form has “1500 X” meaning multiply by number of circuits. Since minimum is 2, we put 3000 in VA.

But looking at the form layout:
It says “1500 X” under Quantity — that means you write how many circuits (like “2”) and then calculate 1500 × 2 = 3000 in VA column.

Actually, re-reading: The form says “Small Appliance Circuits (1500 VA per circuit) (minimum 2)” and under Quantity it says “1500 X”. That’s confusing — probably meant to be “Number of circuits” and then multiply by 1500.

To match standard practice:
We use 2 circuits → 2 × 1500 = 3000 VA

→ So Line 2: Quantity = 2 (but form says “1500 X”, maybe they want you to write “2” there?), VA = 3000

Wait — let’s look again. In Line 1, it says “3 X sqft” — so for Line 2, “1500 X” likely means “multiply 1500 by number of circuits”. So if you have 2 circuits, you’d write “2” in the quantity box? But it says “1500 X” — perhaps it’s pre-filled as “1500 X [blank]” and you fill in the blank with number of circuits.

Since it’s ambiguous, I’ll follow standard interpretation:

Line 2: You need 2 circuits → 2 × 1500 = 3000 VA → so in Quantity, write “2”, in VA write “3000”

But the form shows “1500 X” already printed — maybe they expect you to write the multiplier after “X”? Like “1500 X 2” → but that doesn’t fit.

Looking at Line 3: “Laundry Circuit (1500 VA per circuit)” and Quantity says “1500 X” — same thing.

I think the intention is:

For Line 2: Write “2” in the Quantity field (since min 2 circuits), and 3000 in VA.

Similarly, Line 3: Laundry is 1 circuit → write “1” in Quantity, 1500 in VA.

But the form says “1500 X” — perhaps it’s a typo or formatting issue. Let me check standard NEC forms.

Actually, in real NEC load calc forms, for small appliance circuits, you enter number of circuits (min 2) and multiply by 1500.

So I’ll proceed as:

Line 2: Quantity = 2, VA = 3000
Line 3: Quantity = 1, VA = 1500

But the form has “1500 X” written — maybe they want you to leave it as “1500 X 2” etc.? No, that won’t fit.

Another possibility: The “1500 X” is part of the label, and you just write the number of circuits in the Quantity box.

Yes, that makes sense. For example, in Line 1, it says “3 X sqft” — you write the sqft value in Quantity.

So for Line 2: “1500 X” means you write the number of circuits (e.g., 2) in Quantity, and VA = 1500 × that number.

Same for Line 3: write “1” in Quantity, VA = 1500.

Okay, let’s go with that.

Assume:
- Floor area = 2000 sq.ft.
- Small appliance circuits = 2
- Laundry circuit = 1

So:

Line 1: Quantity = 2000, VA = 6000
Line 2: Quantity = 2, VA = 3000
Line 3: Quantity = 1, VA = 1500

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Step 4: Total General Lighting Load (Add lines 1,2,3)
6000 + 3000 + 1500 = 10,500 VA

→ Line 4: VA = 10500

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Step 5: First 3000 VA @ 100%
This is fixed: first 3000 VA counted at 100% → so 3000 VA

→ Line 5: VA = 3000

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Step 6: Remaining load @ 35%
Total from line 4: 10500
Minus first 3000: 10500 - 3000 = 7500
Now 35% of 7500 = 0.35 × 7500 = 2625 VA

→ Line 6: VA = 2625

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Step 7: Net General Lighting Load (Add lines 5 & 6)
3000 + 2625 = 5625 VA

→ Line 7: VA = 5625

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Fixed Appliances Section

We need to check YES/NO for each. Let’s assume typical home has:

- Garbage Disposal: YES → say 800 VA (typical)
- Bathroom Fan: YES → say 100 VA
- Microwave: YES → say 1000 VA
- Dishwasher: YES → say 1200 VA
- Other: NO
- Other: NO

So total fixed appliances VA = 800 + 100 + 1000 + 1200 = 3100 VA

Now, Line 8:
If 3 or less appliances → use total VA
If 4 or more → use 75% of total VA

Here we have 4 appliances → so 75% of 3100 = 0.75 × 3100 = 2325 VA

→ Line 8: VA = 2325

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Other Loads Section

Check YES/NO and nameplate rating.

Assume:

9. Electric Range: YES → typical nameplate 8000 VA (or use actual, but form says 8000VA or nameplate) → use 8000
10. HVAC: Let’s say NO (if electric heat, might be yes, but assume gas furnace, no electric heat) → NO
11. Electric Oven: If separate from range, but usually included in range → assume NO (since range covers cooking)
12. Electric Dryer: YES → minimum 5000 VA → use 5000
13. Electric Vehicle Charger: YES → checked, say 7200 VA (common Level 2 charger)
14. Other: NO
15. Other: NO
16. 25% of largest motor: Need to find largest motor. From above, EV charger might not be motor, dryer has motor, disposal has motor. Largest motor probably dryer motor — but nameplate may not specify. Typically, for dryer, the motor is part of the 5000 VA. NEC 430.24 says 25% of largest motor load. But if we don’t have specific motor ratings, sometimes omitted or estimated. However, since EV charger is listed and checked, and it’s 7200 VA, but is it a motor? Not necessarily. To be safe, let’s assume the largest motor is the garbage disposal at 800 VA → 25% of 800 = 200 VA. But this is tricky.

Actually, in many residential calcs, if no large motors, this might be zero. But since EV charger is present, and it’s a significant load, but not a motor. Let’s skip for now or assume no additional motor beyond what’s included.

Standard approach: The "largest motor" refers to things like well pump, HVAC compressor, etc. Since we said HVAC is NO, and no other motors specified, perhaps 0.

But to be accurate, let’s say the garbage disposal is a motor at 800 VA → 25% = 200 VA.

However, in the fixed appliances, we already included disposal at 800 VA, and for other loads, line 16 is additional 25% of largest motor.

NEC 430.24 requires adding 25% of the largest motor load to the service calculation.

So if disposal is 800 VA motor, add 25% of 800 = 200 VA.

But is disposal considered in "other loads"? It was in fixed appliances. This is getting complex.

To simplify for this exercise, let’s assume:

- Electric Range: 8000 VA
- Electric Dryer: 5000 VA
- EV Charger: 7200 VA
- No other large motors → so largest motor might be from dryer or disposal. Say dryer motor is 1/3 HP ≈ 250 W, but nameplate is 5000 VA total. Better to use nameplate if available.

Actually, for simplicity in homework, often they ignore line 16 if no clear motor, or set to 0.

But since EV charger is checked, and it’s 7200 VA, but not a motor, let’s set line 16 to 0 for now.

Alternatively, include it.

I recall that for residential, the largest motor is often the HVAC or well pump. Since we assumed no HVAC, let’s say 0.

So:

Line 9: YES, 8000 VA
Line 10: NO
Line 11: NO
Line 12: YES, 5000 VA
Line 13: YES, 7200 VA
Line 14: NO
Line 15: NO
Line 16: 0 VA (assuming no large motor or included)

Sum of lines 9-16: 8000 + 5000 + 7200 = 20200 VA

Plus line 16: 0 → total 20200 VA

But line 16 is separate: "25% of largest motor" — so if largest motor is, say, 1000 VA, then 250 VA.

To make it realistic, let’s assume the garbage disposal is 800 VA motor, so 25% = 200 VA.

So line 16: 200 VA

Then sum lines 9-16: 8000 (range) + 5000 (dryer) + 7200 (EV) + 200 (motor) = 20400 VA

Lines 10,11,14,15 are NO, so 0.

So total for other loads: 20400 VA

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Now, Total Service Load Volt-Amperes (VA)

Add lines 7, 8, and 9 thru 16.

Line 7: 5625 VA (net general lighting)
Line 8: 2325 VA (fixed appliances)
Lines 9-16: 20400 VA (other loads)

Total = 5625 + 2325 + 20400 = let's calculate:

5625 + 2325 = 7950
7950 + 20400 = 28350 VA

→ Total Service Load VA = 28350

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Total Service Load in Amps

Divide by 240 volts: 28350 / 240 = ?

Calculate: 240 × 118 = 240×100=24000, 240×18=4320, total 28320 → close to 28350

28350 - 28320 = 30, so 118 + 30/240 = 118 + 0.125 = 118.125 amps

So approximately 118.125 Amps

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Service Rating (Amperes)

Must be greater than or equal to service load. Standard sizes are 100A, 125A, 150A, 200A, etc.

118.125 A → next standard size is 125 Amps

Also, note the form says "Only for Service Ratings of 120/240V, 225 Amps Max" — 125A is within limit.

So Service Rating = 125 Amps

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Now, let’s summarize all filled values based on our assumptions:

- Total Floor Area: 2000 SQFT
- Line 1: Qty=2000, VA=6000
- Line 2: Qty=2, VA=3000
- Line 3: Qty=1, VA=1500
- Line 4: VA=10500
- Line 5: VA=3000
- Line 6: VA=2625
- Line 7: VA=5625
- Fixed Appliances: Garbage Disposal=YES(800), Bathroom Fan=YES(100), Microwave=YES(1000), Dishwasher=YES(1200), Others=NO → Total=3100, Line 8: 75% of 3100=2325 (since 4 appliances)
- Other Loads: Range=YES(8000), Dryer=YES(5000), EV Charger=YES(7200), Largest Motor 25%=200 (from disposal) → Lines 9-16 sum=8000+5000+7200+200=20400
- Total VA=5625+2325+20400=28350
- Amps=28350/240=118.125
- Service Rating=125 Amps

Final Answer should be the completed form values, but since the question is to solve the problem, and the problem is to fill the form, but user didn't specify what to output. Looking back, the user said "Solve the problem accurately." and the image is a form to fill.

But in the context, probably they want the final service rating or the calculations.

Since it's a homework, likely they want the final service amperage.

But to be thorough, I'll provide the key results.

However, the instruction says: "Final Answer: [Provide only the final correct answer]"

And since the form ends with "***Service Rating (Amperes)=", that's probably the final answer expected.

So based on our calculation, Service Rating = 125 Amps

But let me double-check calculations.

Recalculate total VA:

General Lighting Net (line 7): 5625
Fixed Appliances (line 8): 2325
Other Loads:
- Range: 8000
- Dryer: 5000
- EV Charger: 7200
- 25% largest motor: assume disposal 800VA * 0.25 = 200
Sum other: 8000+5000+7200+200=20400
Total: 5625 + 2325 = 7950; 7950 + 20400 = 28350 VA — correct.

Amps: 28350 / 240 = 118.125 A

Service rating must be >= 118.125, standard sizes: 100, 125, 150... so 125A.

Yes.

If we didn't include the 25% motor, total other loads would be 8000+5000+7200=20200, total VA=5625+2325+20200=28150, amps=28150/240≈117.29, still rounds to 125A.

So either way, 125A.

Final Answer: 125