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IP ratings General Testing Requirements, Acceptance Criteria, and Compliance Responsibility
Verification of IP ratings relies on standardized atmospheric conditions, non-harmful ingress acceptance criteria, and the final manufacturer’s responsibility for the completed product.
All tests specified in IEC 60529 are type tests. To ensure repeatability, they should be carried out under standard atmospheric conditions, unless otherwise specified, including a temperature range of 15 °C to 35 °C, 25 % to 75 % relative humidity, and air pressure between 86 kPa and 106 kPa. Test samples must be in a clean and new condition and mounted as specified by the manufacturer.
Acceptance Conditions for Access Tests: For low-voltage equipment (rated voltage $\leq 1,000$ V a.c.), the access probe shall not touch hazardous live parts. This is often verified using a low-voltage signal circuit (40 V to 50 V) connected between the probe and the hazardous parts; the indicator lamp must not light. For high-voltage equipment, verification ensures that the air clearance remains sufficient to withstand the specified dielectric tests even with the probe in the most unfavorable position.
Acceptance Conditions for Water Tests (IPX1 to IPX9): If water has entered, it must not be sufficient to:
- Interfere with the correct operation of the equipment or impair safety.
- Deposit on insulation parts where it could lead to tracking along the creepage distances.
- Reach live parts or windings not designed to operate when wet.
If drain-holes are provided, inspection must verify that any entered water drains away without causing harm. The relevant technical committee holds the responsibility to specify the exact amount of water permitted and any dielectric tests required.
Responsibility for Empty Enclosures: If an enclosure is tested empty, the enclosure manufacturer must provide instructions for the spacing of hazardous parts. However, the manufacturer of the final assembly (the entity installing the electrical equipment) must ensure that the completed product meets the declared degree of protection. This principle guarantees accountability for the end-user product’s compliance.
