IP66 is the working minimum for any enclosure that stays inside a mushroom house, and IP67 or IP69K is what you need on anything that is still in the room during a high-pressure wash or a cook-out. Standard industrial boxes rated IP44 or IP54 do not survive the combination of saturated air, spore-laden dust and aggressive disinfectants. The first digit matters as much as the second: in a growing room it always has to be a 6.
What do the two digits in an IP rating mean?
An IP code has two digits, and growers tend to look only at the second one.
- First digit (0–6) — protection against solid particles. In a mushroom house this must always be 6, meaning the enclosure is dust-tight. The threat is not industrial dust but spores, substrate particles and casing debris settling on a terminal block.
- Second digit (0–9) — protection against water. This is the number you actually choose, and it should follow your cleaning routine rather than the equipment catalogue. It ranges from a low-pressure hose to close-range jets of hot water under pressure.
Which rating belongs where on the farm?
| Rating | What it withstands | Where it belongs on a mushroom farm |
|---|---|---|
| IP65 | Water jets from any angle, low pressure | Boxes cleaned with a hose or a damp cloth, outside the direct spray line |
| IP66 | Powerful water jets | Junction boxes and control panels on shelving and on harvesting equipment — the working minimum |
| IP67 | Total dust-tightness plus temporary immersion | Components that stay in the room through steam sterilisation |
| IP69K | Close-range jets at 80–100 bar and up to 80 °C, to DIN 40050-9 | Anything sanitised with a pressure washer |
Why does a cook-out damage boxes that survive the wash?
Steam sterilisation is harder on enclosures than the washdown itself, and for a reason that is easy to miss. When the room is taken to 60–70 °C the air inside a sealed box expands. When the room cools down quickly afterwards, the pressure difference pulls moist air, and with it condensate, back through the smallest imperfect seal. Nothing is sprayed at the box, yet water ends up inside it.
This is the failure that an IP67 specification is meant to stop. Immersion-grade sealing keeps condensate away from the circuitry during those thermal transitions, which is exactly when standard IP65 boxes let it in.
Why is the rating on the sticker only half the answer?
An IP code describes a new, correctly assembled enclosure. Three things decide whether it still holds after a season of production.
- Chemical resistance of the housing. Disinfectants are corrosive. Enclosures need high-grade plastics or treated metals that do not become brittle or chalky after repeated exposure to sanitisers.
- Gasket condition. The rubber seal is the weak link — an IP69K box with a cracked or badly seated gasket leaks like an unrated one. Inspect the seals at least once a year, and after any thermal cycle that was harder than usual — a cook-out, or a room taken down and brought back quickly.
- Cable glands. The point where the wire enters the box is the most common failure point of all, because cables get pulled and moved during harvest. Professional compression glands keep the rating under that movement; a slit grommet does not.
What does GrowTime specify on its own equipment?
On NEWTON picking lorries the control components sit in a sealed electrical box, and the drive detaches quickly, so the trolley can be disinfected in the growing room instead of being wheeled out of it. The same logic applies to the fixed electric drive, where the housing and the gland set matter more than the motor itself.
Lighting is part of the same problem. Guidance and work lighting must be sealed against internal condensation, or the spectrum the pickers rely on is dimmed by moisture inside the lens — which is why the LED lamp PC IP69 Edison carries an IP69-class housing rather than a general-purpose one.
What if the rating is not enough?
The most reliable protection is not a higher IP code — it is removing the sensitive component before the water arrives. Drive units and battery boxes that unplug in seconds can be cleaned dry, on a bench, while the room is being sprayed. If you are specifying equipment now, treat detachability and IP rating as one decision, not two.
Related reading
- What should be detachable for easier sanitation
- Preventing corrosion on wheels and moving parts
- Maintenance schedule for electric winches and platform lifts
- All articles: GrowTime Knowledge
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