Quick Hits

⚡ Quick Hit: The Fastened-in-Place Appliance Discount

Article 120 — Branch-Circuit, Feeder, and Service Load Calculations

Episode 13

🏠 THE QUICK HIT

Got four or more qualifying fastened-in-place appliances in a dwelling?

You may be able to apply a 75% demand factor to their combined nameplate load.

But there's an important exclusion list.

📖 120.53 — Fastened-in-Place Appliances

For one-family, two-family, or multifamily dwellings, a 75% demand factor is permitted when the qualifying appliances:

• Are fastened in place

• Are rated 1/4 hp or greater, or 500 watts or greater

• Are supplied by the same feeder or service

• Total four or more appliances

⚡ THE RULE

When the requirements are met:

Combined nameplate load × 75%

That's effectively a 25% reduction from the combined nameplate load for this calculation.

🚫 WHAT DOESN'T QUALIFY?

The 75% demand factor does not apply to:

1️⃣ Fastened-in-place household cooking equipment

2️⃣ Clothes dryers

3️⃣ Space-heating equipment

4️⃣ Air-conditioning equipment

5️⃣ Electric vehicle supply equipment (EVSE)

💡 WHY THIS MATTERS

These loads have their own calculation requirements elsewhere.

Don't simply throw them into the fastened-in-place appliance calculation to get the 75% demand factor.

🎯 TEST YOURSELF

A dwelling has:

• A fastened-in-place water heater

• A garbage disposal

• A dishwasher

• An exhaust fan

All are 500 watts or greater and supplied by the same service.

Per 120.53, what demand factor can be applied to their combined nameplate load?

A) 100%

B) 50%

C) 75%

D) 0% — appliances never get a demand factor

👇 What's your answer?

🧮 SHOW YOUR MATH

There are 4 qualifying appliances.

They meet the stated rating threshold and are supplied by the same service.

Therefore:

4 qualifying appliances → 75% demand factor

Example

If their combined nameplate load were 10,000 VA:

10,000 VA × 75% = 7,500 VA

✅ ANSWER

C) 75%

The four appliances meet the conditions for the permitted 75% demand factor.

⚠️ THE GOTCHA

The important part isn't just remembering 75%.

Remember the excluded loads.

Cooking equipment, clothes dryers, space heating, air conditioning, and EVSE aren't simply bundled into this calculation.

📚 KEEP EXPLORING

⚡ More Quick Hits

Continue exploring the JoshTheSparky Quick Hits library.

🧠 Brain Busters

Test what you know with JoshTheSparky Brain Busters.

❓ Question of the Week

Take the latest JoshTheSparky Question of the Week.

📓 Sparky's Journal

Go deeper into electrical thoughts, lessons, discoveries, and experiences in Sparky's Journal.

📊 Sparky Weekly

Follow the latest progress, discoveries, projects, and industry updates in Sparky Weekly.

📚 Sources

Review the references and resources used throughout JoshTheSparky.com in the JoshTheSparky Sources library.

🧭 QUICK HIT NAVIGATION

← Back to Article 120 Quick Hits

← Back to the 2026 NEC Quick Hits

⚠️ EDUCATIONAL NOTICE

This Quick Hit is an educational explanation based on the author's understanding of the NEC. It is not a substitute for the official NEC, applicable local amendments, manufacturer instructions, or the determination of the Authority Having Jurisdiction (AHJ).

Always verify the requirements applicable to your specific installation.

The National Electrical Code® and NEC® are registered trademarks of NFPA. JoshTheSparky.com is not affiliated with, sponsored by, or endorsed by NFPA.