Electrical – Should light bulbs above showers be “steam proof”

bathroomelectricalrecessed-lightingsteamwaterproofing

In replacing the lighting in my apartment with LED bulbs, I noticed that the recessed can lighting above the shower (to be fair, the light is centered on the shower curtain) does not appear to be steam proof.

I'm only assuming that the bulb/fixture should be rated for use above a shower, but I could be totally wrong about that.

In addition to / regardless of any NEC codes that may be at play here, what kind of symptoms might one experience with a non steam proof light vs a steam proof light (if such a thing exists)?

The only possibly related problem I've had with the light in the three years I've lived in the place is that it seems to be in need of replacement a bit quicker than the rest, but this could easily be attributed to the fact that the light is frequently left on since it's the only bathroom light.

Best Answer

As pointed out by others, luminaires above or near a tub/shower must be "steam-proof" (rated for damp locations). This means the fixture will be sealed in some way, to prevent moisture from entering the housing and causing damage and/or an unsafe environment.

NEC 2008
410.10 Luminaires in Specific Locations.
(D) Bathtub and Shower Areas. No parts of cord-connected luminaires, chain-, cable-, or cord-suspended luminaires, lighting track, pendants, or ceiling-suspended (paddle) fans shall be located within a zone measured 900 mm (3 ft) horizontally and 2.5 m (8 ft) vertically from the top of the bathtub rim or shower stall threshold. This zone is all encompassing and includes the space directly over the tub or shower stall. Luminaires located within the actual outside dimension of the bathtub or shower to a height of 2.5 m (8 ft) vertically from the top of the bathtub rim or shower threshold shall be marked for damp locations, or marked for wet locations where subject to shower spray.

Corrosion

The major concern here would be corrosion inside the fixture, which can lead to dangerous heating, arcing, shorting, etc.

Heat

Corrosion on contacts increases the resistance of the circuit, which can lead to excess heat, which in turn can lead to increased resistance. Given the right circumstances, wires/contacts can be heated to the point of ignition.

Arcing and Shorting

In some fixtures, contacts can be in very close quarters with each other. If corrosion builds up causing the gap between contacts to reduce enough, arcing can become a problem. Similarly, if the gap closes completely, a short can be created.

PITA

Corrosion in fixture can simply lead to a frustrating situation. If the screw base of a bulb becomes corroded enough, the bulb could become difficult or impossible to remove. This could lead to the fixture needing replacement, or at least an annoying bulb change experience.

Ground Faults

As we all know, water conducts electricity (in most cases). Because of this a deadly ground fault situation can be created, if luminairs are allowed to get excessively damp or wet. If enough moisture enters the fixture to cause dripping, a solid stream of conductive water could bring electricity within reach of a well grounded individual. In this scenario, a simple touch of the light could be deadly.

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