Dust-Tight (Dust-Tight, IP First Digit 6)
The first digit of the IP code being 6 means that no measurable amount of dust entered the enclosure in the test carried out in a dust chamber. Digit 5, on the other hand, does not block dust completely; it only limits it to a level that will not disturb the device's operation. The difference between them shows up in the life of contacts and connectors.
The test is carried out in a chamber containing fine talc dust and with a slight vacuum created inside the enclosure; this is the most demanding condition, because the dust is actively drawn inside. An enclosure rated 6 admits no dust; one rated 5 may admit a limited amount but its function is not impaired.
- Why it matters: even non-conductive dust accumulates between a relay contact and a connector pin and raises the contact resistance. Cement and metal dust additionally combine with moisture and form a conductive bridge.
- Difference from IP54: IP54 is the same as IP64 on the water side; the distinction is exactly on the dust side. In a dusty workshop this single-digit difference noticeably changes the maintenance interval.
- In the field: do not open the cover in a dusty environment; if you have to open it, first clean the outside of the enclosure, otherwise you carry the dust inside yourself.
The IP64 and IP67 declarations of AXI remote controls both have 6 as the first digit, that is, they are in the dust-tight class.
The context in which this term is used: Complete guide to the IP protection class