What is the IP Code?
The IP Code is the classification system defined in IEC 60529 that uses two digits to state how well an enclosure protects against the ingress of solid objects and dust (first digit) and of water (second digit). A sensor rated IP67 is therefore dust-tight and survives temporary immersion, while a control cabinet rated IP54 is dust-protected and resists splashing water. Officially IP stands for International Protection, but in practice it is almost always read as Ingress Protection. In Europe the standard is adopted as EN 60529, published in the Netherlands as NEN-EN-IEC 60529.
🧠 How is an IP Code structured?
An IP Code consists of the letters IP, two characteristic numerals and, optionally, one or two letters:
- First numeral (0–6) — protection against solid objects and dust, and against access to hazardous parts
- Second numeral (0–9) — protection against water, from dripping to hot water at high pressure
- Additional letter (A–D) — optional, used only when protection against access is better than the first numeral indicates
- Supplementary letter (H, M, S, W) — optional, adds information about the application or the test
An X means that the characteristic was not tested or no requirement applies: IPX7 has been tested for water but says nothing about dust. The current consolidated version of IEC 60529 is edition 2.2 from 2013, which combines the second edition of 1989 with amendments from 1999 and 2013. The 2013 amendment added IPX9.
🧱 What does the first digit mean?
| Digit | Protection against | Test and meaning |
|---|---|---|
| 0 | No protection | — |
| 1 | Objects > 50 mm | Back of the hand, large body surfaces |
| 2 | Objects > 12.5 mm | Fingers; the test finger must not touch live parts |
| 3 | Objects > 2.5 mm | Tools, thick wires |
| 4 | Objects > 1 mm | Thin wires, small screws |
| 5 | Dust-protected | Talcum powder (75 µm sieve) for 8 hours; limited dust allowed provided operation is not impaired |
| 6 | Dust-tight | Same dust test with underpressure inside the enclosure; no dust may enter |
💧 What does the second digit mean?
| Digit | Protection against | Test according to IEC 60529 |
|---|---|---|
| 0 | No protection | — |
| 1 | Vertically dripping water | 1 mm/min for 10 minutes |
| 2 | Dripping water, tilted 15° | Four positions of 2.5 minutes |
| 3 | Spraying water up to 60° from vertical | About 10 l/min, at least 5 minutes |
| 4 | Splashing water from all directions | Oscillating tube or spray nozzle, 10 l/min |
| 5 | Water jets | 6.3 mm nozzle, 12.5 l/min, at about 3 m, 1 min per m² |
| 6 | Powerful water jets | 12.5 mm nozzle, 100 l/min, at about 3 m |
| 7 | Temporary immersion | Up to 1 m depth for 30 minutes |
| 8 | Continuous immersion | More severe than IPX7; depth and duration agreed with the manufacturer |
| 9 | High-pressure, high-temperature water | 80 °C, 14–16 l/min, 8–10 MPa (80–100 bar) |
Alongside this sits IPX9K from ISO 20653, the road-vehicle standard that grew out of the German DIN 40050-9. The test closely resembles IPX9: water at 80 °C and 80–100 bar from 10–15 cm, applied at 0°, 30°, 60° and 90° for 30 seconds per angle while the item rotates on a turntable. In food and beverage processing, IP69K is the usual designation for equipment cleaned with high-pressure washers.
🔤 Which additional letters exist?
The additional letters state that protection against access to hazardous parts is better than the first numeral suggests: A (back of hand), B (finger), C (tool, 2.5 mm) and D (wire, 1 mm). A code such as IP20B is rare, because the first numeral usually covers access protection already.
The supplementary letters add context: H for high-voltage apparatus, M and S when the water test was carried out with moving parts (such as the shaft of an induction motor) running or stationary respectively, and W for suitability under agreed weather conditions.
🔄 What is the difference between IP67, IP68 and IP69K?
A common mistake is to assume that a higher second digit includes every lower one. Up to IPX6 that holds: anything that passes IPX6 also meets IPX5. From IPX7 upwards the code is not cumulative. Immersion applies a static, even water pressure; a water jet applies a dynamic, local load. An enclosure can pass the first and still leak under the second, for example because a jet pushes a seal out of place.
That is why you often see dual markings such as IP66/IP67 or IP65/IP68, meaning the product was tested both ways. IEC 60529 calls such a product suitable for versatile application, whereas IPX7 or IPX8 without a jet rating only covers restricted application (immersion).
For IP68 the manufacturer sets the conditions, for example 3 m for 24 hours. Two IP68 products are therefore not automatically comparable; always check the depth and duration in the datasheet. IP69K, in turn, says nothing about immersion. A proximity sensor on a meat-processing line therefore often carries IP66/IP67/IP69K on its datasheet.
🏭 Which IP rating is used where in industry?
| Application | Typical IP rating | Notes |
|---|---|---|
| Components inside the cabinet (PLC, power supplies, relays) | IP20 | Finger-safe; the cabinet provides the rest |
| Control cabinet in a dry, dusty production hall | IP54 / IP55 | Dust-protected, resists splashing water |
| Cabinet or HMI in a wet production area | IP65 / IP66 | Dust-tight, resists (powerful) water jets |
| Outdoor field sensors and transmitters | IP66 / IP67 | Rain, driving water, temporary immersion |
| Food processing with washdown | IP66 / IP67 / IP69K | Daily cleaning with hot water and chemicals |
| Submersible pump or well sensor | IP68 | Conditions as specified by the manufacturer |
A variable frequency drive is often IP20 as standard for cabinet mounting, with field-mount versions available in IP55 or IP66. NEN-EN-IEC 61439 for low-voltage switchgear assemblies requires at least IP2X for an enclosed assembly, and IEC 60204-1 for the electrical equipment of machines requires at least IP22 for controlgear enclosures. Those are minimums; the environment usually dictates a higher rating.
🌍 How does the IP Code relate to NEMA, IK and Ex?
In North America, enclosures are specified by NEMA 250 types. These go further than IP: they also cover corrosion, oil and coolant, ice formation and construction. A NEMA type can therefore be converted approximately to an IP Code, but not the other way round.
| NEMA type | Approximate IP | Extra in NEMA |
|---|---|---|
| Type 1 | IP20 | Indoor, general purpose |
| Type 3R | IP24 | Outdoor, rain and ice formation |
| Type 4 | IP66 | Hose-down, indoor and outdoor |
| Type 4X | IP66 | As Type 4, plus corrosion resistance |
| Type 6P | IP68 | Prolonged submersion, corrosion resistance |
| Type 12 / 13 | IP54 | Oil, coolant, dust |
Mechanical impact resistance lies outside the IP Code. That is covered by the IK code from IEC 62262: from IK01 (0.14 joule) via IK08 (5 joules) to IK10 (20 joules), with IK11 (50 joules) added by an amendment in 2021. An outdoor enclosure rated IP66 and IK10 is therefore dust-tight and watertight and can also take a heavy blow.
Explosion protection is yet another matter. A dust-tight IP6X enclosure is not automatically suitable for an Ex zone. That is governed by ATEX and the IEC 60079 series, with their own protection concepts such as flameproof enclosures or increased safety. The IP Code does return there as a supplementary requirement: under IEC 60079-7, an Ex e enclosure with bare live parts must achieve at least IP54, and one containing only insulated live parts at least IP44.
🛠️ How do you choose the right IP rating step by step?
- Describe the environment — indoor or outdoor, dry or wet, what kind of dust (fine, conductive, explosive), temperature and condensation
- Determine the cleaning method — wiping by hand (IP54), hose (IP65/IP66) or high-pressure hot water with chemicals (IP69K)
- Consider immersion — can the device end up under water in a pit or during a flood? Then choose IP67 or IP68 with a dual marking
- Check the whole chain — a cabinet’s rating only holds with the right cable glands, connectors, fans and antenna feed-throughs, for example for an edge device with a 4G modem; one IP54 gland turns an IP66 cabinet into an IP54 cabinet
- Mind condensation — a sealed outdoor cabinet breathes as temperatures change; fit a pressure-equalisation element or a cabinet heater
- Record it — include the IP rating in the functional specification, in the CE documentation and in the list of field components, so that maintenance orders replacement parts with the same rating
Example: a sensor on a conveyor in a dairy plant is cleaned every day with 80 °C water at high pressure and sometimes sits under water in a drip tray. The right choice is a stainless-steel sensor rated IP66/IP67/IP69K, an M12 connector with the same rating and a cable that withstands the cleaning agents.
❓ Frequently asked questions
What does IP65 mean?
IP65 means an enclosure is dust-tight (first digit 6) and protected against water jets from a 6.3 mm nozzle (second digit 5). IP65 is a common rating for operator panels and cabinets in production areas that are cleaned with a hose. For immersion or high-pressure cleaning, IP65 is not sufficient.
Is IP68 better than IP67?
IP68 protects against longer or deeper immersion than IP67, but the manufacturer defines the exact depth and duration. For IP67 the test is fixed at up to 1 m for 30 minutes. Because the IP Code is not cumulative from IPX7 upwards, an IP68 product is not automatically resistant to water jets; that requires a dual marking such as IP66/IP68.
What is the difference between IP69 and IP69K?
IP69 comes from IEC 60529 and was added in 2013, while IP69K comes from ISO 20653 for road vehicles and originated in the German DIN 40050-9. Both test with 80 °C water at 80–100 bar, but the test set-up and procedure differ. In the food industry, IP69K is the designation most often requested.
What IP rating does a control cabinet need?
A control cabinet needs at least IP2X under NEN-EN-IEC 61439, and IEC 60204-1 requires at least IP22 for machine controlgear enclosures. IP54 is common in a dusty hall, IP65 or IP66 in wet or outdoor locations. Make sure cable glands, fans and feed-throughs carry the same IP rating as the cabinet itself.
Can I convert a NEMA type to an IP rating?
A NEMA 250 type can be converted approximately to an IP rating, for example NEMA 4X to IP66. The reverse is not possible, because NEMA also sets requirements for corrosion, oil and ice formation that the IP Code does not cover. An IP66 enclosure therefore does not automatically meet NEMA 4X.
Is an IP67 enclosure suitable for an Ex zone?
No, an IP67 enclosure is not automatically suitable for an Ex zone. Potentially explosive atmospheres are governed by ATEX and IEC 60079, with their own protection concepts and certification. In those areas the IP Code is only a supplementary requirement alongside Ex certification.
📌 In summary
The IP Code from IEC 60529 uses two digits to express how well an enclosure is protected against dust (0–6) and water (0–9), but from IPX7 upwards the code is not cumulative. Choose based on environment, cleaning method and immersion, use dual markings such as IP66/IP67/IP69K for washdown, and remember that every cable gland and connector must meet the same rating.