The Numbers Describe Tests, Not Quality
An IP rating is often treated as a score, where a higher number means a better product. It is not. The two digits describe two specific laboratory tests defined in IEC 60529, and the right rating is the one that matches the conditions your fitting will actually face. Over-specifying adds cost and can worsen thermal performance, while under-specifying produces failures that appear long after handover.
What Each Water Rating Is Tested Against
IP65 is verified with a 6.3 mm nozzle delivering roughly 12.5 litres per minute from about three metres, for at least one minute per square metre with a three-minute minimum. IP66 uses a 12.5 mm nozzle at roughly 100 litres per minute under the same duration rules, which is close to industrial pressure washing. IP67 requires the enclosure to survive thirty minutes fully immersed at a depth of one metre, with no ingress of water in a quantity that would affect operation.
Above those sits IP68, agreed between manufacturer and user for continuous immersion, and IP69K, defined by ISO 20653, which uses water at about 80 degrees Celsius delivered at 80 to 100 bar. IP69K is specified for food and beverage plants where equipment is steam-cleaned, and it is rarely needed elsewhere.
Matching the Rating to the Application
For covered car parks, plant rooms, and dry industrial interiors, IP65 is usually sufficient and keeps thermal design simple. For exposed facades, washdown zones, food processing areas, and any surface cleaned with a pressure washer, IP66 is the sensible specification. For drainage chambers, below-grade areas, and locations that flood, IP67 is the correct choice, because a jet test does not prove anything about standing water.
When you are choosing between ratings for a waterproof LED light, the useful question is not which number is highest but which failure the site can actually produce. Driving rain is not a pressure washer, and a pressure washer is not a flood.
Luxsky Product Perspective
We publish the tested rating for each variant rather than a single figure for the family, because the sealing detail changes with length, end caps, and cable entry. Our LED triproof lamp range covers IP65 for general industrial use, IP66 for washdown and exposed locations, and IP67 where flooding is possible, with the test report matched to the exact model shipped.
Send us the installation location and the cleaning method, and we will recommend the rating that fits rather than the highest one we can supply. That approach usually reduces cost and improves reliability at the same time.
Frequently Asked Questions
Does IP67 automatically include IP66 protection? No. The ratings are independent tests. A fitting rated IP67 has passed an immersion test, which does not guarantee it has passed the jet test, so look for a dual rating such as IP66 and IP67 where both risks exist.
Is IP66 enough for a food factory? For most zones, yes. Where equipment is steam-cleaned at high temperature, IP69K is the correct specification.
Does a higher IP rating reduce light output? Indirectly, yes. Tighter sealing limits heat dissipation, so a well-designed high-IP fitting needs a larger thermal path for the same wattage.
Should outdoor fittings always be IP67? Not necessarily. Most outdoor luminaires fail from ultraviolet exposure and thermal cycling rather than immersion, so UV-stable materials and good thermal design often matter more than the third digit.
