How to read IP ratings: the complete meaning of the two digits in EN/IEC 60529
What do the two digits in IP54, IP65, IP67 and IP68 mean? A digit-by-digit reading of solid protection (0-6) and water protection (0-8) per EN/IEC 60529, with common ratings for industrial cable protection.
Short answer: in an IP code, the first digit rates protection against solids and dust (0-6) and the second against water (0-8); the two are tested independently - IP67 covers brief immersion but not necessarily powerful jets, and IP68 is the continuous-immersion class. The governing standard is EN/IEC 60529.
First digit: solids (0-6)
5 = dust-protected (limited dust, no harmful effect); 6 = dust-tight (no dust ingress). In industrial plants this is the line that matters: dusty workshops and grinding stations require 6, general workshops are fine with 5. Ratings 0-4 cover larger objects and are rarely marked alone on modern equipment.
Second digit: water (0-8)
| Digit | Test | Typical use |
|---|---|---|
| 4 | Splashing water | Damp indoor areas |
| 5 | 6.3 mm nozzle jet | Washable enclosures |
| 6 | 12.5 mm powerful jet | Decks, heavy wash-down |
| 7 | 1 m immersion, 30 min | Accidental submersion |
| 8 | Continuous immersion, depth/time manufacturer-declared | Long-term or buried |
Two common mistakes: 7 is not "higher" than 6 - 6 is spraying, 7 is soaking; a product may carry both IP66 and IP67. And the conditions of 8 are declared by the manufacturer, so two IP68 products may differ in depth and duration - always check the stated conditions.
The letter X and supplementary letters
X in IPX7 means "not rated", not "not waterproof". Supplementary letters A-D mark access protection beyond the minimum; H/M/S/W relate to high voltage, moving or stationary parts and weather - rarely used in cable protection.
Applying ratings to conduit systems
A conduit system is rated as a whole: body plus fittings. The corrugated body with its continuous steel helix is rarely the weak point - the fittings are. Indoor cabinets: IP54. Medical equipment wiped with disinfectant: IP65. Outdoor and wash-down: IP66/IP67 with sealed fittings. IP68 parameters of the PVC corrugated conduit system are listed on the product pages; see also IP68 vs IP67 in practice and the FAQ GEO section.
