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Exploring IPX3, IPX4, IPX3b, and IPX4b Test Methods: A Comprehensive Analysis

Updated: Sep 28, 2023

Exploring IPX3, IPX4
Exploring IPX3, IPX4

The IPX3, IPX4, IPX3b, and IPX4b test methods are fundamental in IEC 60529 standard, which classifies

electrical equipment enclosures regarding protection against the entry of water and dust. Each classification has a specific application, employing distinct methods to simulate different levels of water exposure.

IPX3 Testing with Oscillating Tube and Spray Nozzle Methods.

The IPX3 testing method involves the use of an oscillating tube or a spray nozzle as specified in the product standards. Below are the conditions for the oscillating tube method, conforming to the guidelines presented in the norm IEC 60529.

a) Oscillating Tube Method

Equipment and Setup:

  • Utilize the oscillating tube device as shown in Figure 4 of the IEC 60529.

  • The tube has spray holes covering an arc of 60° on either side of the center point.

  • Test Procedure:

    • Place the enclosure to be tested at the center point of the semicircle created by the oscillating tube.

    • The tube oscillates through an angle of 120° (60° on either side of the vertical) at a rate that completes one oscillation in about 4 seconds.

    • The test duration is 5 minutes. The oscillation continues for the first 5 minutes.

    • Rotate the enclosure horizontally by 90° and continue the test for an additional 5 minutes.

  • Tube Specifications:

    • The oscillating tube should have a maximum acceptable radius of 1,600 mm. (we have added a chart of all arc specifications below this article)

  • Adjustments for Complete Wetting:

    • If certain parts of the enclosure aren't adequately wetted during the test, the enclosure's support can be adjusted up or down.

    • Prefer the hand-held spray nozzle device (Figure 5) if complete wetting is challenging with the oscillating tube.

b) Spray Nozzle Method

  • Equipment and Setup:

    • Use the spray nozzle device as depicted in Figure 5 of the IEC 60529.

    • Ensure the counterbalanced shield is in place.

  • Test Procedure:

    • Adjust the water pressure to achieve the specified delivery rate, typically ranging from 50 kPa to 150 kPa.

    • Maintain a constant water pressure throughout the test.

    • The test duration is 1 minute per square meter of the calculated surface area of the enclosure (excluding any mounting surface), with a minimum duration of 5 minutes.

These testing procedures are essential for determining the degree of protection offered by the enclosure against water ingress as per the IPX3 standard.

IPX4 Testing with Oscillating Tube and Spray Nozzle Methods

The IPX4 testing method assesses an enclosure's resistance to water ingress, particularly water sprayed from different directions. The test can be conducted using either the oscillating tube or spray nozzle methods, as specified in the product standards. Here are the detailed conditions for both methods:

a) Oscillating Tube Method

  • Equipment and Setup:

    • Utilize the oscillating tube device as shown in Figure 4 of the IEC 60529.

    • The tube has spray holes covering the entire 180° of the semicircle.

  • Test Procedure:

    • Adjust the total flow rate according to the specifications provided in Table 9, measured using a flow meter.

    • The tube oscillates through an angle of almost 360° (180° on either side of the vertical) at a rate that completes one oscillation in about 12 seconds.

    • The test duration is 10 minutes.

    • If not specified otherwise in the relevant product standard, perforate the support for the enclosure under test to prevent it from acting as a baffle. Spray the enclosure from every direction by oscillating the tube to the limit of its travel in each direction.

b) Spray Nozzle Method

Equipment and Setup:

  • Use the spray nozzle device as depicted in Figure 5 of the IEC60529.

  • Remove the counterbalanced shield from the spray nozzle.

Test Procedure:

  • Spray the enclosure from all practicable directions.

  • Maintain a rate of water flow and spraying time per unit area as specified in numeral 3.

These testing procedures are essential for evaluating the enclosure's ability to withstand water sprayed from various angles, simulating real-world conditions and providing valuable insights into its ingress protection.

IPX3b and IPX4b: Application of Portable Shower

The addition of the letter "b" indicates the use of a portable shower for larger samples that do not fit under the regular oscillating tubes set up, that the bigger arc is R1600. In the IPX3b method, water is applied horizontally from a portable shower. Similarly, IPX4b utilizes a portable shower to spray water horizontally in all directions.

The water flow rate in tests with a portable shower is 10 litres per minute, with a pressure between 8 and 15 psi (pounds per square inch). It's crucial to highlight that the portable shower pressure is critical to ensure effective operation. In a shower with 0.5 mm diameter holes, the ideal operating pressure is between 10 and 12 psi. Excessive pressure may indicate hole blockage, necessitating proper cleaning or maintenance.

Water Quality for Testing: The Importance of Deionization and Softening

The water quality used in tests is crucial to ensure precise and consistent results. Preferably, the water should be deionized, free of minerals and ions that could interfere with the test results.

To achieve this purity, deionized water undergoes a process to remove ions, eliminating impurities. In addition to deionization, it is essential to consider water softening, especially in regions where water has a high mineral content. Softening reduces mineral concentration, preventing the formation of deposits that could harm the testing equipment.

There are various methods to soften water, including the use of ion exchange resins, chemical precipitation, and reverse osmosis. The choice of method depends on the available water quality and specific test requirements.

Speed and Angles of Oscillating Arcs

In addition to variations in test methods, considering the speed of the oscillating arms and the different test angles is essential. The angles can be at 60 degrees in relation to the center of the arc, as generally applied, or even at 90 degrees, as specified in IEC 60335 for household appliances. In some situations, 180-degree tests may be necessary to assess comprehensive water protection.

Arcs per Radii: Nozzle Diameter and Quantity

For the IPX4 test, which involves using a spray nozzle, the arcs per radii R200 to R1600 are critical in assessing water ingress protection. Each radii is associated with a specific nozzle diameter and quantity, affecting the intensity and coverage of water spray. The table below illustrates these parameters for each radii:

Radii (mm)

Nozzle Diameter

IPX3 Water Flow (LPM)

IPX3 Nozzle Quantity

IPX4 Water Flow (LPM)

IPX4 Nozzle Quantity

















































Understanding these parameters is crucial for precise testing, ensuring products meet the specified water resistance standards effectively.

Conclusion: Choosing the Appropriate Method

In understanding the intricacies of IPX3, IPX4, IPX3b, and IPX4b testing methods, precision is key. Careful consideration of essential factors such as the speed and angles of oscillating arcs, water flow, pressure, nozzle specifications, and water quality in tests using a portable shower is crucial. Additionally, proper water softening and appropriate nozzle diameter and quantity for varying arc radii play significant roles.

Ensuring products meet the necessary safety standards provides confidence and security to consumers. The choice of the correct test method, in alignment with the specific product and its intended use, is fundamental in accurately evaluating its resistance to water ingress.

This article aims to provide a comprehensive understanding of these IPX ratings and the corresponding testing methods. However, for precise guidance and the correct application of these methods, it's imperative to refer directly to the IEC 60529 standard and other reliable sources of information. Adhering to these standards empowers manufacturers, regulators, and consumers to maintain a high level of product safety and quality.

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