IP67 vs IP68 vs IP69K: What Sensor Protection Ratings Really Mean

The Two Numbers in "IP67"

IP stands for Ingress Protection, defined by IEC 60529. The first digit is solids, the second is liquids.

First digit — solids

Second digit — liquids

So IP67 = dust tight + survives 1 m of water for 30 minutes. IP68 = dust tight + continuous immersion at a specified depth. IP69K = dust tight + survives steam-cleaner-grade jets.

The Trap: IP68 Is Not Automatically Better Than IP67

Both are "6" on solids. The liquid digit differs, but IP68 has no fixed test condition — the manufacturer states the depth and duration. An IP68 rating of "1.5 m for 24 hours" is a real, common specification, and it is not the same as "50 m for a year".

Worse, the two tests are physically different:

• IP67 is a 30-minute soak.
• IP68 is a long soak, often at higher pressure.

A sensor can pass one and fail the other, depending on how the seal behaves under sustained pressure versus short exposure. When immersion matters, ask for the actual IP68 depth and duration, in writing.

Also: IP69K does not imply IP68. A sensor built for steam jets may not survive prolonged soaking, and vice versa. They test different failure modes.

NEMA vs IP: The North American View

NEMA also covers things IP does not — corrosion resistance, gaskets ageing, and enclosure construction. That is why industrial sensors for the US market are frequently dual-rated: our PT9420EX carries IP67, IP68, NEMA 4, 4X and 6 simultaneously. If you are exporting to North America, dual rating saves a specification argument.

What This Looks Like Across a Real Product Range

In a 149-model position sensor catalogue, the distribution is revealing:

• IP67 — 68 models. The industrial default. Rain, washdown, outdoor mounting with a drip loop.
• IP68 — 41 models. Submersible duties: outdoor gates, tanks, marine, flood-prone pits.
• IP65 — 19 models. OEM and in-cabinet builds.
• IP50 — 18 models. Clean, dry, enclosed.
• NEMA 4 / 4X / 6 — 53 / 36 / 40 models quoted alongside IP.

Roughly half the catalogue reaches IP67 or better. The other half is perfectly adequate — if the installation really is dry. Specifying IP68 "just to be safe" costs money and, in some designs, compromises the cable exit.

Choosing the Right Rating

Six Places Seals Actually Fail

1. The cable gland. A body rated IP68 with a standard gland installed upward collects water. Mount the gland downward or use a connector version.
2. The connector. An M12 connector is only as sealed as its mating half and its torque. Under-torqued connectors are the number one field failure.
3. The cable jacket. A polyurethane jacket resists oil and abrasion; PVC does not. In coolant or hydraulic oil, the jacket fails before the seal does.
4. Thermal cycling. Heating expands the air inside; cooling draws moisture in through any imperfect seal. Breather membranes solve this in sealed enclosures — ask whether the sensor has one.
5. Pressure differential. A sensor rated IP67 at the surface may leak at 3 m depth because the pressure is continuous, not a 30-minute soak.
6. Mechanical damage. A nicked cable jacket near the gland wicks water straight into the housing. Strain relief is a sealing feature, not a convenience.

Washdown Reality Check

Food, beverage and pharmaceutical plants increasingly use IP69K because cleaning involves 80 °C water at high pressure with caustic foam. A sensor that survives IP67 will often fail within months in that regime — not from water ingress at first, but from chemical attack on the seals and the cable jacket.

If your cleaning procedure matters, specify:

• IP69K rating, or IP67 with proven chemical compatibility;
• 316 stainless housing rather than painted aluminium;
• a cable jacket rated for the cleaning agent, not just for water;
• the mounting orientation that lets water drain.

Frequently Asked Questions

Is IP68 better than IP67? For continuous immersion, yes. For everything else, not necessarily — and IP68 without a stated depth and duration is an incomplete specification.

Can an IP67 sensor be used outdoors? Yes, in rain and splash. Not in standing water or where it will be submerged. Use a drip loop and mount the cable exit downward.

What does IP69K mean? Protection against high-pressure, high-temperature water jets (80 °C, 80–100 bar, close range) — the steam-cleaner test. It says nothing about prolonged immersion.

Does IP rating cover corrosion? No. IP covers solids and liquids only. Corrosion resistance comes from housing material and finish — NEMA 4X addresses it, IP does not.

What is the difference between IP67 and NEMA 6? They test the same idea — temporary submersion — with different procedures and different agency oversight. Industrial sensors often carry both to satisfy different regional specifications.

Specify Sealing Correctly

Tell us how the sensor is cleaned, whether it is ever submerged, and what chemicals it meets. We will recommend the housing, gland and cable jacket combination rather than just quoting an IP number.

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