An IP (Ingress Protection) rating is defined by IEC 60529, and it’s one of the more precisely testable specs a buyer can verify — which also makes it one of the more commonly misused in marketing copy. The rating consists of two digits: the first (0–6) rates protection against solid particles like dust; the second (0–9) rates protection against liquids. IPX7, for example, means the solids test wasn’t performed — the X doesn’t mean zero protection, it means untested.
The Misconception Worth Correcting
The most consequential misunderstanding isn’t about what any single digit means — it’s the assumption that a higher second digit automatically covers lower ones. IEC 60529 explicitly treats immersion testing (IPX7, IPX8) and water jet testing (IPX5, IPX6) as separate, independent test protocols. An enclosure rated IP68 has been tested for sustained submersion in still water. It has not necessarily been tested against a pressurized water jet from an angle — a different physical stress entirely.
In practice: a product rated IP67 (dust-tight, temporary immersion to 1 meter for 30 minutes) has no certified protection against a directional pressure hose. If the actual use case is factory washdown or high-pressure cleaning rather than accidental submersion, IP65 or IP66 is the relevant spec, not IP68 — regardless of which number sounds more impressive on a listing.
What the Common Ratings Actually Test
- IP54 — limited dust ingress, splash resistance from any direction. Suitable for light rain exposure, not jets or immersion.
- IP65 — fully dust-tight, resistant to low-pressure water jets from any direction. This is the rating actually being described when a product is marketed as handling “rain and hose-down,” but it is not submersible.
- IP67 — dust-tight, temporary immersion up to 1 meter for 30 minutes in still water. Says nothing about jet or spray resistance.
- IP68 — dust-tight, continuous immersion under conditions the manufacturer specifies. IEC 60529 itself does not fix a universal depth or duration for IP68 — one manufacturer’s IP68 could mean 1.5 meters for one hour, another’s could mean 3 meters for 72 hours, and both are legitimately “IP68” without a stated figure being false.
- IP69K — the most demanding water-jet rating, but worth flagging precisely: it is not part of IEC 60529. It’s defined by a separate standard, ISO 20653, originally written for automotive and food-processing washdown equipment. A product can be dual-rated (e.g., IEC 60529’s IP68 plus ISO 20653’s IP69K tested separately), but treating IP69K as simply “a higher number within the same IEC 60529 scale” is a common and understandable mistake — it’s a different standard body’s test. IP69K conditions typically involve water at 80°C, roughly 100 bar of pressure, delivered at close range from multiple angles — and, notably, IP69K certification does not by itself confirm immersion resistance; a product needs a separate IPX7/IPX8 rating for that.
A Second Misconception: IP Ratings Don’t Test Durability
IP ratings measure ingress protection only — dust and water. They say nothing about a product’s resistance to drops, vibration, or mechanical shock, which fall under a separate standard (commonly MIL-STD-810H for ruggedized equipment). A device marketed as “IP68 rugged” is not necessarily drop-tested; if drop resistance matters for the use case, that’s a distinct spec to verify separately, not something implied by a high IP rating.
What to Ask a Supplier
- Which lab issued the certification, and under which edition of IEC 60529? The current consolidated edition is 1989+A1:1999+A2:2013; a cited test report should reference it directly, not just a printed number on packaging.
- For IP68 claims specifically: what depth and duration does the manufacturer specify? “IP68 rated” without a stated depth/time figure is a marketing claim, not a verifiable spec.
- If IP69K is claimed, is it tested separately under ISO 20653, and does the product also carry an independent IPX7/IPX8 rating if immersion resistance is also needed for the use case?
- If mechanical durability (drops, vibration) matters for the application, ask for that spec separately — it’s not covered by any IP rating regardless of how high the number is.