The IP code on an assembly describes how the enclosure limits the entry of solid objects and water. It is written as IP followed by two digits: the first covers solids, the second covers water. IP30, IP54 and IP65 are common entries in low-voltage assembly documentation, and the range covered by a given type-test report is stated on its sample page.
Reading the two digits
| Code | First digit (solids) | Second digit (water) |
|---|---|---|
| IP30 | Objects 2.5 mm and larger | No stated protection |
| IP54 | Dust-protected | Splashing water |
| IP65 | Dust-tight | Water jets |
The first digit runs from 0 to 6 and the second from 0 to 9 in the general IP scale. The two digits are independent: a higher first digit says nothing about water, and a higher second digit says nothing about dust. Reading them as a pair avoids a common mix-up when a schedule simply says “IP54 or better”.
Start from the installation environment
- Clean, dry indoor switchroom. A lower first digit with no stated water protection is often the starting point.
- Dust, fibres or airborne particles. Look at the first digit and at how filters and ventilation openings are detailed.
- Occasional splashing or wash-down. The second digit becomes the governing choice, together with door seals, gland plates and cable entries.
- Outdoor or semi-outdoor locations. Consider rain, condensation, solar gain and the drainage path in addition to the IP code.
IP30 to IP65 is the range commonly recorded in low-voltage assembly type-test reports. The value that applies to a specific configuration is the one on its sample page.
Protection and temperature rise are linked
An enclosure with a higher degree of protection exchanges less air with its surroundings, so temperature-rise verification belongs in the same conversation as the IP rating. Ventilation openings, filter fans, heat exchangers and air conditioners each change the path by which air, dust and water can enter, and each has a place in the assembly’s design verification. Reading the IP rating together with the temperature-rise item in the report’s summary of test items keeps both in view.
What to state in the enquiry
- Indoor or outdoor location, ambient temperature range and installation altitude.
- Dust, moisture, wash-down or chemical exposure expected in service.
- Target IP code, plus any limits on ventilation openings, filter fans or cable entry direction.
- Which report covers the proposed enclosure, and how the temperature-rise item was verified for it.
Written this way, the IP line in an enquiry can be answered against a drawing, with the enclosure details stated alongside the code.
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