Corrosion is a common problem affecting LED lighting fixtures. It is not only a cosmetic issue, but also threatens product performance and shortens service life.
Prevention must begin "from the source"—from the fundamentals such as product and material selection, coating treatment, etc.—rather than merely addressing symptoms after degradation has already begun. This article explains why corrosion occurs and how to prevent it at the source.
Why is Corrosion a Common Problem for Lighting Fixtures?
Corrosion is the gradual chemical degradation of metal parts, and rust is just one common form of it. LED light fixtures are semiconductor devices, so they don’t rust themselves, but their metallic housings, brackets, screws and circuitry can corrode when exposed to moisture, temperature fluctuations, or pollutants.
Common factors like high humidity, salt spray or industrial vapors attack metal surfaces. For example, swimming pools and coastal areas generate chloride-rich atmospheres – evaporating droplets leave salt crystals that “eat” at steel over time. Even indoors, chemical fumes or condensation can cause corrosion of contacts and wiring.
In practice, a lightly rusted finish is often cosmetic, but unchecked corrosion will weaken joints, reduce electrical conductivity, and shorten fixture life.
Anti-corrosion Material Selection
Stainless steel (especially marine-grade 316/316L) and aluminum are popular choices because of their inherent corrosion resistance.
Where possible, use powder-coated or anodized aluminum to add extra protection. For example, marine-grade aluminum alloy and 316L stainless resist salt air and moisture, while tough polycarbonate lenses and UV-stable plastics prevent water ingress.
Non-metal fixtures, such as fiberglass or engineered plastics, are even more corrosion-proof.
Selection for Lights with Protective Certification
When selecting products, look at corrosion ratings or IP/NEMA ratings. Fixtures rated IP65/66 or higher are sealed against dust and jets of water.
In very aggressive environments (ISO corrosion class C4/C5), only high-end alloys or specially coated lights should be used. It is recommended to use duplex or 316 stainless steel for C4 areas and use acid-resistant alloys for C5 areas.
Modern fixtures often list their corrosion class or UL/NEMA listing, so we should match the light to your environment, such as marine-rated for salt spray, NSF-listed for pools and C1D2/ATEX for chemical zones.
Light Structure and Sealing
A well-sealed fixture is a corrosion-fighting fixture. All outdoor lights should have gaskets and seals at any joint or opening.
Properly sealed cable glands and screws, often using silicone sealant or rubber O-rings, prevent moisture entry.
Some designs include a pressure-equalization vent – a breathable membrane that lets air escape while blocking liquid – so that pressure changes don’t blow seals out.
Protective Coating Treatments
A high-quality powder coating or paint layer acts as a barrier against moisture and oxygen.
Steel components should ideally be galvanized (hot-dip zinc plated) so they’re “coated inside and out” against rust. Aluminum parts are often anodized, thickening their oxide film for extra durability.
Inside the fixture, electronics can also be shielded. Conformal coatings on PCBs and drivers create a moisture-proof layer. These internal coatings protect sensitive components from salt spray or condensation, much like sunscreen protects skin.
Installation Environment
Minimize exposure to corrosive media where possible. For example, avoid mounting lights directly under pool-edge water spray or near lawn sprinklers.
In coastal areas, install fixtures high above the sand/mist or under protective overhangs. In enclosed spaces with high humidity or chemical fumes, improve ventilation or use dehumidifiers.
