An IP rating tells you how well an electrical enclosure keeps solids and water out, and it is one of the most important specifications when choosing a distribution box or cabinet. Selecting too low a rating for an outdoor or washdown location risks water ingress; over-specifying adds cost that a project may not need.
This guide explains how to read an IP rating, compares the common grades and shows how to match one to an installation.
How to Read an IP Code
"IP" stands for Ingress Protection and is followed by two digits. The first digit describes protection against solid objects and dust; the second describes protection against water. An X in place of a digit means that factor was not assessed — for example, IPX5 was tested for water but not for dust.
First Digit: Protection Against Solids and Dust
- 5 — dust-protected: dust may enter but not in enough quantity to interfere with normal operation.
- 6 — dust-tight: no dust enters even under a vacuum test, the highest practical level.
Second Digit: Protection Against Water
- 4 — splashing water from any direction.
- 5 — low-pressure water jets from a nozzle.
- 6 — powerful water jets and heavier seas.
- 7 — temporary immersion to a defined depth and time.
Common Ratings Compared
| Rating | Protection | Typical Use |
|---|---|---|
| IP54 | Dust-protected, splash-resistant | Indoor or sheltered locations |
| IP55 | Dust-protected, jet-resistant | Covered outdoor, light washdown |
| IP65 | Dust-tight, jet-resistant | General outdoor installation |
| IP66 | Dust-tight, powerful jets | Exposed coastal / washdown sites |
| IP67 | Dust-tight, temporary immersion | Temporary flooding risk |
Match the Rating to the Scene
- Dry indoor rooms: IP54 is usually sufficient against occasional splashes and dust.
- Covered but unheated outdoor: IP55 handles driven spray and condensation.
- Fully exposed outdoor: IP65 is the common baseline for direct weather.
- Coastal or hose-wash areas: IP66 adds protection against powerful jets and salt spray.
IP vs NEMA Ratings
Buyers sourcing from both European and North American suppliers may also see NEMA enclosure types, which describe protection in a similar way but use a different scale. NEMA ratings additionally consider factors such as corrosion and icing, so they are not a direct one-to-one conversion. As a rough guide, NEMA 4 is broadly comparable to a dust-tight, hose-directed IP65/IP66 level, while NEMA 4X adds corrosion resistance, similar to a stainless enclosure. When a specification lists a NEMA type, confirm the equivalent IP rating with the supplier rather than assuming an exact match.
The Rating Is Only as Good as Its Seals
An IP rating applies to a correctly assembled enclosure. In practice, protection depends on a continuous door gasket, properly tightened waterproof cable glands and intact sealed seams. A single unsealed cable entry will drop a cabinet well below its labeled rating regardless of the door. This is why the same enclosure can perform differently depending on how it is installed and wired.
Common Mistakes to Avoid
- Assuming a higher IP number alone means durability — material and corrosion resistance still matter outdoors.
- Forgetting that cable entries and mounting holes must be sealed to retain the rating.
- Specifying immersion ratings for surface weather exposure when IP65 or IP66 already fits.
B2B Sourcing Notes
When requesting a quote, state the required IP rating, the installation environment, the number and size of cable entries, and the enclosure material. Factory-direct suppliers can build enclosures to a target IP, fit matched gaskets and glands, produce custom OEM sizes and verify sealing and finish before shipment.
Specifying an Enclosure for a Project?
Share the installation location and exposure for a recommendation on IP rating and a wholesale quote, typically returned within 24 hours.
Frequently Asked Questions
What does IP65 mean?
IP65 means the enclosure is dust-tight and protected against low-pressure water jets from any direction, making it a common choice for general outdoor use.
Is IP54 enough for outdoor use?
IP54 suits sheltered or indoor locations; fully exposed outdoor installations usually call for IP65 or higher.
What is the difference between IP65 and IP66?
Both are dust-tight, but IP66 withstands more powerful water jets, suiting exposed coastal and washdown environments.
Does a higher IP rating prevent corrosion?
No. IP ratings address ingress of dust and water; corrosion resistance depends separately on the enclosure material, such as stainless or coated steel.
Can cable glands change the IP rating?
Yes. Entries must use correctly rated, properly sealed glands or the enclosure will not achieve its labeled protection.
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