A light marked IP65 looks waterproof until the first hose-down shift ends it with a fogged window and a dead driver. The label is not wrong; the code was read as a promise it never made. This guide decodes an IP rating for machine vision lights under IEC 60529: what each digit tests, what IP65, IP67 and IP69K survive in a real cell, and where the code stops, because oil, coolant and cleaning chemicals sit outside it. You will finish able to name the minimum rating for a washdown, splash or dusty cell, spot the ingress paths no rating covers, and place cables and controllers so the printed rating holds on the machine.
Read the code: two digits, two independent tests
IP stands for Ingress Protection, and the code comes from IEC 60529, the standard that grades how well an enclosure keeps solids and water out. The first digit runs 0 to 6 for solids and accidental contact; 0 means no protection at all. The second digit runs 0 to 8 for water, with 9K as a separate hot, high-pressure spray grade. A digit replaced by the letter X was not tested, so IPX4 says nothing about dust and IP6X says nothing about water. Trailing letters such as H, M, S or W mark special test conditions and rarely appear on lighting data sheets.
The two digits are independent results, not a ladder: passing immersion does not earn the jet grade. Data sheets that carry both print them side by side, for example IP65/IP67. The IEC's IP ratings page is the primary source, and the same digits govern camera housings, where a walk-through of what IP42, IP55 and IP65 mean reads them from the enclosure side.
The first digit: dust in five thresholds
Digits 1 to 4 are about fingers and tools, not plant air:
| Digit | Keeps out | Test probe |
|---|---|---|
| 1 | objects 50 mm and larger | 50 mm sphere |
| 2 | objects 12.5 mm and larger | standard test finger, 80 mm long |
| 3 | objects 2.5 mm and larger | 2.5 mm rod |
| 4 | objects 1 mm and larger | 1 mm wire |
| 5 | harmful dust deposits | talc dust for 2 to 8 h, limited ingress allowed |
| 6 | all dust | talc dust for 2 to 8 h, no ingress |
Only 5 and 6 matter around a light. Digit 5 admits some dust but nothing that harms the electronics; digit 6 is dust-tight. Choose 6 whenever the air carries fine powder such as flour, sugar, toner or cutting dust, because powder works into gasket lips that a finger test never touches. In a clean assembly area, digit 5 is usually enough.
The second digit: nine water grades and one more
Water is where cells diverge, so the tests are worth reading with their numbers:
| Digit | Threat | Test values |
|---|---|---|
| 1 to 3 | drips, condensation, spray angled up to 60° from vertical | drip and oscillating-spray rigs |
| 4 | splashing from any direction | oscillating spray |
| 5 | low-pressure jets, any direction | 6.3 mm nozzle, 12.5 L/min, about 30 kPa, roughly 3 m away |
| 6 | powerful jets, any direction | 12.5 mm nozzle, 100 L/min, about 100 kPa, roughly 3 m away |
| 7 | temporary immersion | 1 m deep for 30 min |
| 8 | continuous immersion | depth and time declared by the maker |
| 9K | hot, high-pressure spray-down | 80 °C water, 8 to 10 MPa, 14 to 16 L/min, from 10 to 15 mm |
The IP code reference table lists each rig. Grade 9K is not "more than 8": it replaces the immersion ladder with a close-range hot spray-down from road-vehicle practice. Grade 8 is open-ended by design, because the maker declares the depth and time, so two IP68 lights can mean different conditions.
Worked example: how much water the hose carries
Take a stainless conveyor over baked goods, cleaned every shift with an operator-held wash gun. Production splashes nothing; cleaning is the water event, and the rating decision reads the jet rows.
An IPX5 jet moves 12.5 L/min. An IPX6 jet moves 100 L/min at about 100 kPa. The step between them is 100 ÷ 12.5 = 8 times the flow, at 100 ÷ 30 ≈ 3.3 times the pressure. Now the immersion grade: static water at 1 m presses at
about a third of even the gentler 30 kPa jet. For a light bolted above a line, jets are the brutal test and depth is not, which is why "IP67, so it survives washdown" reads the code backwards.
The decisions for this cell: condensation and drips during production need IPX4. A rinse hose aimed from any direction needs water digit 6 with dust digit 6. If sanitation ends with 80 °C caustic spray-down from a close-range nozzle, the water digit is 9K. Grades 7 and 8 enter only when the cell can flood or the light can take a dunk in a parts washer.
What the code never covers
IEC 60529 tests water. It says nothing about oil mist, cutting fluid, caustic foam, solvents or steam, and an enclosure that holds out water can still be attacked by a fluid that swells its gasket or crazes its window. Treat every oil and coolant question as a materials question answered by the maker's statement on the product page, not by the IP code.
Oil also fails you optically before it fails the seal: a film on a diffuser scatters the pattern and turns a stable inspection into drifting false rejects. The lighting fix for machining-oil false rejects keeps contrast when oil is present, and installing a coolant wash-down pump on a CNC lathe shows where the jet load comes from on the machine side.
Two boundaries remain. IP grades and NEMA types come from different standards with different tests, so never convert one into the other on paper. And the code describes the light, not the camera behind it: few bare industrial cameras carry a jet grade, so the usual fix is a washdown housing selected with the same digit logic, and choosing a machine vision IP rating for an enclosure walks that purchase.
Where water gets in anyway
A rating is earned by the assembly as the maker mounts it: window gasket, cable gland and connector face working together. Four paths cause most field failures.
- Window seal. Heat cycles compress a gasket over time; a light that runs cool keeps its seal longer, which the section below turns into a decision.
- Cable entry. The gland is the usual leak. Run the cable with a drip loop below the connector so water on the cable drips off before it reaches the entry, and never point a gland upward in a wet zone.
- Connectors. The mating face is the weak link of the chain, whatever the body's grade. Keep the first connector out of the jet path. Connectors, adapters and current for controller-to-light cables covers the electrical side of those pairs.
- Orientation. The grade applies in the orientation the maker intends; a light gasketed for jets on its downward-facing window is a mounting the maker never tested sideways.
Standard lighting accessories include the extension cables that make the drip loop and the raised connector possible:
- Size
- Under 50 mm
Match the rating to the cell
Read the row for the worst cleaning step, not for the average shift:
| Cell | Dust digit | Water digit |
|---|---|---|
| Clean, dry assembly area | 5 | 1 |
| Fine powder in the air: flour, toner, cutting dust | 6 | 1 |
| Splash zone above a washer, tank or coolant bed | 6 | 4 |
| Hose-down line, wash gun from any direction | 6 | 6 |
| Cell that can flood, or parts-washer dunk risk | 6 | 7 |
| Food sanitation ending in 80 °C close-range spray-down | 6 | 9K |
For a hose-down conveyor, the food washdown lighting selection checks turn this table into a line-side checklist. The light itself is usually a diffused bar light sized to the field of view; the LS-BAR-1276 is a 372 x 28 mm diffused white bar light on 24 V, a shape that fits most conveyor frames:
- Size
- 200-400 mm
- Type
- Diffused
- Voltage
- 24 V
Lit length follows the field of view, not the washdown plan, and the family stays on 24 V:
| Specification | LS-BAR-1047 | LS-BAR-1276 | LS-BAR-1168 |
|---|---|---|---|
| LED rows | 6 | 4 | 6 |
| Cable length | 500 mm (per dimension drawings) | 500 mm | 1 m |
| Color | – | White | Red |
| Connector type | – | SMR-03V-B | SMR-03V-B |
| Power | – | 11.5 W | 26.9 W |
| Dimension | – | 372 mm × 28 mm × 27 mm | 423 mm × 40 mm × 30 mm |
| Temperature | – | Working temperature: 0 °C to 40 °C (32 °F to 104 °F); Storage temperature: –20 °C to 60 °C (–4 °F to 140 °F) | Working temperature: 0 °C to 40 °C (32 °F to 104 °F); Storage temperature: –20 °C to 60 °C (–4 °F to 140 °F) |
| Humidity | – | 20% to 85% RH (non-condensing) | 20% RH to 90% RH (no condensation) |
| Diffuse plate included | – | Included | PMMA |
| Emitting area dimension | – | 360 mm × 22 mm | 411 mm × 31.6 mm |
| Price | $449.00 | $439.00 | $569.00 |
Values as printed in each product's data sheet; open a part for its drawing and full specifications.
Panel, cables and heat
The light controller never earns a rating by standing in the splash zone. Set it in the electrical cabinet with the PLC and reach the lights over cable. A 4-channel digital unit such as the LS-CTL-0322, 16-24 V output and 8 A total output, is a panel device by design; the light controller category and the light controller finder sort by channels and output type for exactly that panel decision.
- Output
- Constant voltage 24 V
- Channels
- 4 channels
- Control
- Digital
Heat is the quiet enemy of every seal above. A light strobed only during exposure carries a fraction of the average thermal load of one running continuously, and a cooler seal keeps its compression longer, which is the same mechanism that extends LED lifetime L70 under strobe. If the process allows strobing, strobe.
Five checks before you order
- Read both digits on the product page of every shortlisted light. An X means untested; a 0 means no protection.
- Match the water digit to the most aggressive cleaning step. The hose defines the rating, not production splashes.
- Follow the chain. Light, gland, cable and connector each carry their own grade, and the lowest one in the chain is the cell's grade.
- Design the drip loop and connector heights into the bracket, before the first leak teaches you why.
- Re-image after the first washdown. A uniform target shot before and after cleaning exposes condensation haze or brightness drift at once; the lighting stability test before deployment gives you the baseline.
When the bigger number is the wrong answer
Three misreads cost real money. First, IP67 is not IP65-plus: immersion and jets are different tests, and the pressure arithmetic above shows the jets are the harsher ones for a wall-mounted light. Second, grade 9K does not include the immersion grades, and grade 8 does not include 9K; a cell that needs both needs a light printed with both. Third, a higher digit never retroactively includes a lower test, because digits are results, not a ladder.
The decision in one line: for a hose-down cell, dust digit 6 and water digit 6; move the water digit to 9K only when sanitation sprays 80 °C caustic at close range; add 7 or 8 only where flooding is possible; keep the controller in the panel; handle oil and coolant outside the code.
Shortlist from the lights finder, work the choices through the lighting step of the configurator, and if your cell mixes washdown with oil mist, ask through the contact page before you standardize on a part. The lighting topic page collects the rest of the illumination guides.
Questions
Is IP67 better than IP65 for a washdown light?
They test different things. IP67 is immersion 1 m deep for 30 minutes; IP65 is low-pressure jets from any direction. A hose-down cell needs the jet result, so water digit 6, and lights rated for both print the two grades side by side, for example IP65/IP67. Specifying IP67 alone for a washroom is the classic mistake: the immersion pass says nothing about jets.
What IP rating does a food plant washdown light need?
First digit 6, dust-tight, because sanitation foam and flour dust both work into joints. For water: a gentle rinse splashing from any direction is digit 4; a hose wash is digit 6; sanitation that ends in 80 °C high-pressure caustic spray-down from close range is 9K. Pick by the most aggressive step of the cleaning cycle, not by what production splashes.
Does an IP rating protect a light against oil or coolant?
No. IEC 60529 tests water only. Oil and coolant differ in viscosity and chemistry, and they swell or attack seal compounds that shrug off water, so a watertight light can still be ruined by fluid exposure. Keep lights out of direct oil mist, wipe the window at changeover, and buy fluid resistance from the maker's own statement on the product page, never from the IP code.
What does the X in IPX4 mean?
The enclosure was not tested, or is not rated, for that dimension. IPX4 says nothing about dust; IP6X says nothing about water. X is a placeholder for a missing digit, not a zero and not a pass. Read an X rating digit by digit and treat the missing dimension as unknown until the maker states it.
Can a light controller live in the washdown zone?
Keep it out. Controllers are panel devices, with connector blocks and ventilation for their own cooling, and the light's rating does not transfer to them. Mount the controller in the electrical cabinet, land the cables on a drip loop above the spray line, and use extension cables to reach the lights.
Is IP68 always the safer choice than IP67?
IP68 means the maker declares the immersion depth and time, so it is stronger on submersion but still carries no jet grade. A light that survives continuous immersion at the stated depth can still fail a hose-down. For washdown, read the second digit you need and add an immersion grade only where the cell can flood.