Dust Tight or Dust Protected: The Difference IP5X and IP6X

The gap between IP5X and IP6X is not a matter of degree. IP5X permits dust to enter as long as it does not interfere with operation or safety; IP6X permits none.

When IP5X is enough

Equipment with conformal coated boards, sealed bearings and no sliding contacts can tolerate a light dust film indefinitely. In those designs IP5X is a sensible and cheaper specification.

When it is not

Anything with optical surfaces, sliding seals, relay contacts or cooling fans. Dust on a lens degrades the measurement; dust in a fan bearing destroys it. In those cases only IP6X is meaningful, and the enclosure usually needs a vacuum test to prove it.

Test difference

The chamber, powder and duration are identical. The difference is the acceptance criterion and, for IP6X, the option of a partial vacuum inside the enclosure during the test, which pulls dust toward every gap. A product that passes IP5X comfortably may fail IP6X under vacuum, which is the point of the stricter test.

Related technical notes

• Specifying an Outdoor Cabinet: IP Rating Plus Everything Else
• Simulating Rain: When IPX3 or IPX4 Is the Right Model
• When an IP Test Fails: A Structured Way to Find the Path