IP42 LED lighting

The IP rating decides where a fitting can go. Putting an indoor light outdoors does not fail immediately — it fails after a few months of rain, and usually without warranty cover because it was used in the wrong environment. This is the specification most worth checking before ordering, because the consequence lands after installation.

Two digits: the first blocks dust and solids, the second blocks water. IP20 is dry indoor use only. IP44 withstands splashing, suitable for bathrooms and covered porches. IP65 resists water jets from any direction — the minimum for outdoor fittings. IP66 handles powerful jets, for floodlights, street lights and factories where floors are hosed down.

Choosing a higher rating than you need costs nothing but money. One thing is easy to miss, though: the rating applies to the complete fitting installed correctly. A misaligned gasket, an under-tightened cover or a cable entering from the wrong side all void the number printed on the housing — a carelessly fitted IP66 unit still takes in water.