IP68 devices are supposed to be waterproof, yet water ingress is a common issue. How can this happen when the device is rated as dust-tight and waterproof?
IP68 is a laboratory test result, not a permanent waterproof guarantee. Conditions like new products, correct assembly, static environments, specified depth, and time must be met, which is often unrealistic in real-world situations.
Many engineers, buyers, and even device manufacturers face the problem of water ingress despite the IP68 rating. It's a frustrating reality that leads to doubts about the reliability of the IP68 standard and whether higher IP ratings are necessary. However, most IP68 water ingress incidents have little to do with the IP rating itself.
What is the truth about IP68 devices?
IP68 isn't a guarantee against water ingress forever; it's a specific condition laboratory test result. The test assumes the product is new, correctly assembled, in a static environment, submerged to a specified depth for a certain time. Real-world conditions rarely meet these criteria.
A fact many shy away from is that IP68 is not a long-term waterproof promise. It's a result of specific conditions in laboratory testing, which is why real-world applications often fail to maintain these standards over time.
When devices are marked as IP68, it means they've passed a test under ideal conditions. Unfortunately, in practical scenarios, such conditions are hard to replicate, leading to potential water ingress.
What are the common causes of water ingress in IP68 devices?
Devices with an IP68 rating still suffer water ingress due to several factors: seal aging, improper assembly, mismatched cable diameter, high-pressure washing, temperature differences, vibration, and misuse of cable glands. These factors undermine the integrity of the device's waterproof features.
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Seal aging: Seal materials age due to temperature cycles, UV exposure, chemical media, and compression. They harden, lose elasticity, and develop micro-cracks over time, allowing water to seep in gradually.
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Assembly issues: IP68 relies on complete assembly. Cable glands, connectors, blind holes, and screws must be properly secured; otherwise, water finds a way in.
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Cable diameter mismatch: A cable that's too thin or too thick compromises the seal, leading to long-term failure.
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High-pressure washing: IP68 relates to static immersion, not high-pressure washing or fluctuating water pressure, which can force water into devices.
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Temperature differences: Temperature changes cause air inside devices to expand and contract, pulling moisture in if seals are inadequate.
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Vibration and tension: Static tests don't account for vibration, cable tension, or movement, which loosen seals over time.
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Misuse of cable glands: Cable glands are for static cable entry scenarios. Dynamic environments require connectors or molded cable assemblies, not cable glands.
Understanding these causes helps engineers realize that the IP rating isn't the problem; it's the conditions in which devices are used that lead to water ingress.
Can a higher IP rating solve the problem?
Many assume a higher IP rating will prevent water ingress, but this isn't the case. Issues like seal aging, assembly errors, and environmental factors affect devices regardless of the IP number. Even IP69 cannot counteract poor installation or maintenance practices.
Increasing the IP rating isn't a solution. The fundamental issues lie in usage and environmental conditions, not the IP numbers. Higher ratings don't fix seal aging, installation errors, or the effects of vibration and tension.
Rather than focusing on IP numbers, engineers should prioritize system reliability, addressing movement, seal longevity, temperature fluctuations, and maintenance needs. This approach ensures more reliable performance over time.
What is the right engineering approach?
Shift focus from IP ratings to system reliability. Engineers should consider cable movement, seal aging, temperature fluctuations, and maintenance needs. This ensures devices operate reliably in real-world conditions.
The fundamental question isn't whether to use IP68 but whether the device's environment is suited to its capabilities. Engineers must evaluate cable movement, seal aging, environmental temperature changes, and maintenance requirements.
System reliability involves assessing usage scenarios and environmental factors. It ensures devices maintain their integrity and performance over time, rather than relying solely on an IP rating.
When is IP68 appropriate?
IP68 is suitable for static devices with low maintenance needs, specified water depth, and proper selection and installation. Under these conditions, IP68 devices can reliably last 10–15 years.
Despite its limitations, IP68 is useful for static equipment with low maintenance demands, where water depth and exposure time are known, and selection and installation are correctly handled. In these scenarios, IP68 can function for many years without issue.
Understanding the appropriate use of IP68 helps engineers avoid misapplication and ensures devices perform reliably within their specified environments.
Conclusion
Understanding the limitations of IP68 helps identify the true causes of water ingress, focusing on system reliability rather than IP numbers for better device performance.
