Many buyers assume IP68 is simply a better version of IP67. It is not. The two ratings describe two different working conditions, and a higher number does not guarantee a longer service life on your machine.
How to Read an IP Rating
IP stands for Ingress Protection (IEC 60529). The first digit covers dust, the second covers water. The two digits are independent.
- IP5X / IP6X – dust-protected (IP5X) or dust-tight (IP6X).
- IPX4 – splash water from any direction.
- IPX5 / IPX6 – water jet, from normal to powerful.
- IPX7 – temporary immersion, 1 m for 30 minutes.
- IPX8 – continuous immersion, depth and duration declared by the maker.
- IPX9K – high-pressure, high-temperature washdown.
So IP67 means dust-tight plus temporary immersion, and IP68 means dust-tight plus continuous immersion. The dust rating is identical. The only difference sits in the water test.
The Difference Is in the Test, Not the Number
IPX7 is a fixed test: 1 m deep, 30 minutes, identical for every supplier that claims it. IPX8 has no fixed parameters. The manufacturer declares the depth and duration, as long as the condition is harsher than IPX7.
That means one IP68 connector tested at 1.5 m for 24 hours and another tested at 20 m for 7 days carry the same label, yet they are not the same product. Ask for the test report, not the label.
Three Mistakes Buyers Make
- Higher number means better protection. IP67 and IP68 describe still water only. Washdown, coolant and steam need IPX6 or IPX9K.
- The rating assumes a mated connector. An open plug, a missing cap, or a cable whose outer diameter does not match the clamping range loses protection at once. Most water enters through the cable entry, not the mating face.
- Ignoring heat cycles. Heating and cooling make a sealed housing breathe, moisture is drawn in and condenses on the terminals. A vent membrane and a redundant O-ring solve this.
How to Choose in Four Steps
- Environment. Indoor IP54 to IP65; rain and splash IP65 to IP66; puddles IP67; continuous immersion IP68; high-pressure wash IP69K plus IP68.
- Medium. Fresh water, sea water, coolant and oil each need a different seal material.
- Temperature. Silicone for wide temperature range, NBR where oil is present, FKM for aggressive chemicals.
- Documentation. Ask for the IP report with depth and duration, plus salt fog data for outdoor sites.
Frequently Asked Questions
Is IP68 better than IP67? Only when the declared depth and duration match your application. In jet or chemical environments, a well-tested IP67 part can beat a loosely declared IP68.
Can I use an IP67 connector outdoors? Yes, if the housing is UV-stable and the cable entry is properly sealed. IP67 covers rain and occasional standing water, not long-term immersion.
Is IP68 enough for pressure washing? No. Immersion ratings describe static water. Washdown and steam cleaning require IPX6 or IPX9K, ideally combined with IP68.
In short: classify how water reaches your connector first, then match the rating, then ask for the report.