A luminaire is being installed in a location the Code classifies as wet. What does the Code require of that luminaire and its installation?
- It shall be marked as suitable for wet locations, and installed so water cannot enter or accumulate in the wiring compartment, lampholder, or other electrical parts
- BIt shall be supplied by a circuit protected at not more than 15 amperes and wired with weather-resistant flexible cord terminating in a covered outlet box below the luminaire
Circuit rating and cord type do nothing to keep water out of a lampholder. The error path answers a construction and marking question with wiring-method details, and an indoor-rated luminaire in the rain is unchanged by the size of its device.
- CIt shall be mounted at least 8 feet above grade so that rain cannot reach the lens, and aimed downward to shed water from the housing
Height does not keep water out, since wind-driven rain reaches a fixture at any elevation and a wet location classification does not change with mounting height. The error path treats a wet location as a splash zone near the ground.
- DIt shall be sealed at the job site with silicone at every housing joint and at each conduit entry before the luminaire is first energized
Field sealing an indoor-rated housing does not give it a wet-location marking, and it traps the condensation that forms inside. A listed wet-location luminaire is built to drain, which is the opposite of being sealed shut.
Why A is correct
The Code puts the burden on the product marking and on the installation together. The luminaire must carry a marking identifying it as suitable for wet locations, and it must be installed so that water cannot enter or accumulate in wiring compartments, lampholders, or other electrical parts. A damp-location fixture is a lesser rating and does not qualify.
What this question is testing
This tests the pairing of location classification with product marking, a pattern the Code repeats for boxes, receptacles, enclosures, and conductors. Recognizing the pattern lets you answer several questions from one idea.
On the job
The classic failure is a decorative fixture chosen by an owner or designer from a catalog and installed under an open soffit or on an exposed post. It fills with water, the lamp base corrodes, and the ground-fault device on the circuit starts tripping in every rainstorm. Field crews should check the label before hanging the fixture, because once the trim is up and the owner has paid for it, replacing it is a conversation nobody wants. Fixture orientation matters too: many listed wet-location fixtures are only rated when mounted in a specific position.
Memory technique
Wet outside, wet-rated label inside.
Exam tip
When a stem gives you a location classification, your first move is to look for the marking requirement that goes with it.
Where to look it up
Article 410, the early sections on luminaires in specific locations. Confirm which classification applies using the damp and wet location definitions in Article 100.