Humidity is one of the three main factors that cause and accelerate the formation of corrosion/oxidation films. The other two factors are temperature and corrosive particles or gas particles. Two types of electrical connector test methods have been developed in wet environments.

1. Test in steady-state humid environment.
2. Test in a humid environment under temperature cycling conditions.
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Test in steady-state humid environment.
Testing in a steady-state humid environment is a test conducted in an environment where the constant temperature and relative humidity (RH) are constant. It is generally considered to be a test in a static environment, and the results obtained by this test are limited. It is mainly manifested in the following aspects:
1. Determine the sensitivity of the plastic material to thermal expansion, hygroscopicity and dimensional stability;
2. Determine the extent to which the electrical connector system is affected by the oxidation process in a humid environment by a limited method;
3. Determine the potential for surface deterioration of plastic housing.
The two test conditions commonly used for this test are a combination of a temperature of 40 ° C and a relative humidity of 95% (RH) and a test environment combining a temperature of 85 ° C and a relative humidity (RH) of 85%.

Testing in a humid environment under temperature cycling conditions.
Testing in a humid environment under temperature cycling conditions is a test in a dynamic environment. It differs fundamentally from testing in a steady-state environment in that it circulates between two extremes under high humidity conditions. This test method is more commonly used to reveal or detect potential deterioration factors as follows.
Determine the sensitivity of the housing material to thermal expansion, hygroscopicity, and dimensional stability.
The extent to which the electrical connector system is affected by the oxidation process in a humid environment is determined by a limited method.
The extent to which the contact surface is subject to wear in a thermal cycling environment (because the humid environment accelerates the oxidation process).
The oxidation process of the contact material and the wear debris or particles attached to the surface in a humid environment.

More stringent test conditions for temperature/humidity testing
Condition 1 is used for testing where the test conditions are controllable and shielded. Conditions 2 and 3 are used in tests where the test conditions are uncontrollable but shielded. The time of the cycle test is usually random and the time of residence at high and low temperatures is substantially equal. If the equipment (DUT) used in the test has established a reaction to heat, the cycle may be performed at a faster rate. The limited requirement is that the DUT can reach thermal equilibrium within the expected time in each cycle.
It is possible to limit the conventional cycle for special occasions because the actual environment used is difficult to meet, because the humidity may not increase when the temperature is lower than 5 ° C or higher than 100 ° C, so the number of temperature rises may increase. The number of temperature drops will be reduced.
The method of durability testing may vary depending on the purpose of the test being performed. The standard durability test is as follows:
1-48 to 96 hours: Tested in a steady-state humid environment.
2-240 hours: Tested in a humid environment under temperature cycling conditions.
3-500 to 1000 hours: Tested in a humid environment under temperature cycling conditions.
Among them, test condition 1 is used for the evaluation of plastics, and test condition 2 is used for the evaluation of plastics and to determine whether there are major catastrophic problems. Test Condition 3 is used to determine if the product being tested is affected by mechanical failure due to time (such as oxidation and/or wear corrosion in a humid environment). If it lasts for less than 300 hours, it is considered that under these temperature conditions, its function failure can be promoted over time.
Insulation resistance (IR) is used as an assessment of the performance of plastic housing. Resistance (CRCR or LLCR) was used as an assessment of contact surface and electrical stability.