Examen y uso del equipo (listado)

110.3(B) is the one that bites people. If the label says torque a lug to 40 inch-pounds, that is Code, not a suggestion. Ignore the instructions and you have a violation even if everything looks fine.

Inspectors love this section because it is objective. The paperwork either matches the install or it does not.

When it applies

Any time you install a piece of equipment, its listing and the instructions in the box are enforceable. If the label says indoor dry-location only, that is where it goes. If the manufacturer specifies a breaker type, wire size, or mounting orientation, that becomes part of the Code requirement, not a suggestion.

Common mistakes

• Tossing the installation sheet without reading the torque, spacing, or clearance specs.
• Using a device outside its listed environment, like an interior panel on an exposed exterior wall.
• Substituting a breaker brand the panel is not listed to accept.

In the field

I keep the paperwork with the gear until the inspection clears. When an inspector questions a mounting, I hand him the manufacturer sheet and the conversation ends fast.