1. IP protection level (international standard IEC 60529)
The IP code consists of two digits, the first digit for dustproof and the second digit for watertight. For example, IP67 means complete dustproof (level 6) and short-term water immersion protection (level 7).
1. Waterproof level (second digit)
| Grade | Protection | Typical scenarios |
| IPX0 | No waterproof protection | Dry indoor environment |
| IPX1 | Vertical dripping water (1 minute, equivalent to light rain) | Ordinary electronic equipment |
| IPX2 | 15° tilt dripping (15° tilt in each direction) | Wet indoor (such as kitchen) |
| IPX3 | Water spray (60° spray, water pressure 80kPa, for 5 minutes) | Outdoor rainproof equipment (such as street lights) |
| IPX4 | Splashing water (spraying water in any direction, without pressure limit) | Sports watches, drones |
| IPX5 | Low-pressure water spray (nozzle 6.3mm, water pressure 30kPa) | Industrial equipment, automotive electronics |
| IPX6 | High-pressure water spray (nozzle 12.5mm, water pressure 100kPa) | Ship deck, high-pressure cleaning environment |
| IPX7 |
Short-term immersion in water (1 meter deep, 30 minutes) |
Diving cameras, temporary underwater equipment |
| IPX8 |
Continuous immersion (depth and time specified by the manufacturer) |
Underwater sensors, deep sea equipment |
| IPX9K |
High temperature and high pressure spray (80°C hot water, 8-10MPa) |
Automobile engine compartment, high pressure cleaning equipment |
2. Dust protection level (first digit)
| Grade | Protection capability |
| IP0X | No dust protection |
| IP5X | Dust protection (limited intrusion, no impact on equipment operation) |
| IP6X | Complete dust protection (no dust intrusion) |
2. NEMA standards
NEMA grades correspond to IP codes, for example:
- NEMA 4 ≈ IP66 (dustproof, high-pressure water jet protection)
- NEMA 6P ≈ IP67/IP68 (dustproof, submersible)
3. Special standards for the automotive industry
- ISO 20653: For vehicle-mounted connectors, such as IP6K9K (dustproof + high-temperature and high-pressure water jet protection).
- USCAR-2: Waterproof and sealing test standard for automotive electronic connectors.
4. Test methods
- Water spray test (IPX5/X6): Use a standard nozzle to simulate spraying with different water pressures.
- Water immersion test (IPX7/X8): Immerse the connector in a specified water depth for a certain period of time.
- High temperature and high pressure test (IPX9K): 80°C high temperature water + high pressure jet.
5. Selection recommendations
- Outdoor equipment (such as solar panels): IP65/IP66 (rainproof and dustproof).
- Underwater equipment (such as diving equipment): IP68 (depth and time must be specified).
- Automotive electronics: IP67/IP69K (resistant to high-pressure washing and immersion).
- Industrial environment: IP67/IP68 (dustproof and waterproof + corrosion resistant).
6. Precautions
- Sealing materials: Aging of silicone and rubber rings may reduce long-term waterproofness.
- Pressure changes: Changes in water depth pressure or temperature may affect sealing performance.
- Dynamic environment: Vibration or plugging and unplugging may damage the sealing structure (such as vehicle-mounted connectors require dynamic waterproof design).
By reasonably selecting the waterproof level, the reliability of the equipment in complex environments can be significantly improved. The actual selection needs to be considered in combination with specific scenarios, costs and long-term maintenance requirements.
