When an IP Test Fails: A Structured Way to Find the Path

A failed IP test tells you water got in, not where. Finding the path quickly saves a redesign cycle, and there are four reliable methods.

Dye penetrant

Add a fluorescent dye to the test water and inspect under UV after the test. The path shows as a bright trace from the entry point, which is far more informative than a wet patch at the bottom.

Air pressure decay

Pressurise the sealed enclosure to a few kPa and watch the decay, then brush soap solution on suspect joints. Bubbles locate the leak precisely. This works only for enclosures that are meant to be sealed, and it is the fastest method for production screening.

Partial disassembly

Dry the enclosure, then test with one joint taped off at a time. Tedious but definitive for complex assemblies with several potential paths.

Thermal method

Warm the enclosure and look for condensation patterns with an infrared camera immediately after spraying. Wet paths show as cold streaks. Useful where the enclosure cannot be opened.

Related technical notes

• Which Standard Applies: IEC 60529 and Its Product Relatives
• Washdown in Food Equipment: IPX6 Is Only Half the Requirement
• Choosing an IP Test Laboratory: Six Things to Verify