Definitions

Do not skim Article 100. The whole rest of the book leans on it. 'Readily accessible' and 'accessible' are one word apart and a ladder apart in the field.

I have won and lost inspections on definitions alone. Learn them cold and you stop guessing at what a section is really asking for.

When it applies

Article 100 is the dictionary for the whole book. Before you argue about a rule, look up the words in it. When the code says a space is accessible, or a panel is in a dwelling unit, or a conductor is a feeder, those terms have exact meanings here, not whatever you assume on the tailgate.

Common mistakes

• Confusing readily accessible with accessible, they are two different definitions and they change what an inspector will accept.
• Calling every wire a feeder when the code means something specific by feeder versus branch circuit.
• Guessing at labeled versus listed, they are not the same and product approval can hinge on it.

Half the code disputes I have watched go sideways were really just two people using the same word to mean different things. Settle the definition first and the rest of the fight usually disappears.