What is the most important sentence to know in the entire National Electrical Code (NEC)?

Thursday, November 28, 2019

It’s near the beginning of the code, at 110.3(B) Installation and Use, and says:

"Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling."

    Anything electrical installed as part of the construction of a house must be listed or labeled, which are two levels of approval by an agency such as Underwriter’s Laboratory (UL). Part of the approval process is verifying the correct and safe way to install it, so this sentence says that the manufacturer’s instructions trump the code for correct installation. So always be sure to read the folded up paper in the box.

    Unfortunately, we have found that the local building inspector’s interpretation of what should be done may turn out to be the final mandate. As an example, some manufacturers of electric tankless water heaters specify that a pressure relief valve is not necessary, but the local inspector may require it anyway.

    Also, see our blog post What does "listed and labeled" mean for an electrical component?

• • • • • • • • • • • • • • • • • • • • • • • • • • • • 

Here’s links to a collection of some of our other blog posts about BUILDING CODES:

When did the first Florida Building Code (FBC) begin and become effective?

The home inspector says I have construction defects. How did my home pass inspection by the building department? 

What is the difference between prescriptive and performance building codes?

Can a local building department choose to not enforce selected parts of the Florida Building Code? 

 Is the latest edition of the National Electrical Code (NEC) the standard used for the electrical system of new homes?

 Why is the National Electrical Code (NEC) so hard to understand and complicated? 

What is the purpose of the Existing Building Edition of the Florida Building Code?

    Visit our BUILDING CODES page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

 

 

How To Look At A House

McGarry and Madsen's home inspection blog for buyers of  

site-built, mobile/manfuactued and modular homes

(placeholder)

Search

This

Site

Search

This

Site

Attics

Air Conditioner & Furnace Age

AFCI, CAFCI, DFCI, & GFCI

Bathrooms

Aging in Place

Appliances

Click Below  

for Links to Collections

of Blog Posts

by Subject

Cracks

Doors and Windows

Electrical

Energy Efficiency

Fireplaces and Chimneys

Heating and Air Conditioning

Home Inspection

Hurricane Resistance

Electric Receptacle Outlets

Electric Panels

Garages and Carports

Common Problems

Exterior Walls & Structures

Insulation

Insurance

Life Expectancy

Mobile/Manufactured Homes

Older and Historic Houses

Mold, Lead & Other Contaminants

Modular Homes

Metal Roofs

Plumbing

Radon

Pool and Spa

Roof and Attic

Remodeling

Safety

Site

"Should I Buy A..."

Stairs

Termites, Wood Rot & Pests

Structure and Rooms

Wells

Water Heaters

Water Heater Age

Septic Tank Systems

Plumbing Pipes

Sinkholes

When It First Became Code

Park Model Homes

Shingle Roofs

Stucco

Wind Mitigation Form

"Does A Home

Inspector...?"

"What Is The Difference Between..."

Brick

Concrete and Concrete Block

Foundations

4-Point Inspections

Rain Gutters

Condominiums

Crawl Spaces

Building Permits

Clay Soil

Floors

Toilets

Generators

HUD-Code for Mobile Homes

Flat Roofs

Sprinkler Systems

4-Point Inspections

Frequently Asked Questions (FAQ)

Building Codes

Inspector Licensing

& Standards