Examination and Use of Equipment (Listing)
Equipment has to be evaluated for its use and then installed the way its listing and labeling say. Follow the instructions that come in the box.
Why this code exists
A device is only as safe as the conditions it was tested under. Use it outside those conditions and the testing means nothing.
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.
I keep the instruction sheets from every panel I set. When an inspector asks about torque, I hand him the label and the calibrated wrench receipt and we are done.
See full history
- 1937 — Requirement to use equipment per its rating formalized.
- 1978 — Installation per listing and labeling made explicit in 110.3(B).
Related codes
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