IP65 vs IP66: what buyers should know

The first digit of an IP rating covers dust, the second covers water. IP65 and IP66 are both fully dust-tight (6), but IP65 is tested against water jets from a 6.3 mm nozzle while IP66 is tested against powerful jets from a 12.5 mm nozzle.

When IP66 matters

• Food plants and car washes that are cleaned with high-pressure hoses
• Ports and coastal sites exposed to storms
• Flood lights aimed upwards where rain hits the glass directly

For indoor warehouses, IP65 is usually enough. Ask for the test report, not just the label.