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IP Ratings Explained: Why Your Machine Light Dies in a Puddle of Coolant

2026-09-15 17:59:31

IP65, IP67, IP54 — three letters and two numbers that decide whether your LED work light lives for a decade or dies in a season. Here is how to read them, and which rating your shop actually needs.

Coolant is the second most dangerous thing in a machine shop — right after the machine itself. It creeps, it splashes, it finds the one seam you forgot. Most LED work lights don't die of old age. They die of coolant ingress, one drop at a time.

Here is what an IP rating really protects, and how to stop throwing lamps away.

1. IP: Two Numbers, One Story

IP stands for Ingress Protection, followed by two digits. The first digit is how well the lamp resists solid objects — dust, chips, fingers. The second is how well it resists water.

First digit 5: dust-protected (some dust may enter, but no damage).
First digit 6: dust-tight (no dust at all).
Second digit 4: splashing water from any direction.
Second digit 6: powerful water jets.
Second digit 7: temporary immersion (30 min, 1 m).

That is the whole code. The rest is marketing.

IP65

Dust-tight + jets

IP67

Dust-tight + immersion

Cause of failure: coolant

2. Why the Rating on the Head Matters More Than the Body

On a machine work light, the weak point is never the LED array. It's the seal between the lens and the housing, and the cable entry. A lamp can be IP67 on paper and leak like a colander where the cable gland meets the wire.

When you inspect a candidate light:

Check the cable gland — it should be a sealed, threaded gland with a rubber insert, not a slot.
Check the lens seal — the joint should be flush and gasketed, not a bare snap-fit.
Check the driver placement — the driver should live in the dry zone of the fixture, or be sealed itself.

These are the three places a "waterproof" light stops being waterproof.

3. Which Rating for Which Job

Rating	What it survives	Best for
IP54	Splashes, dust build-up	Bench lights, dry machining
IP65	Water jets, dust-tight	CNC turning with flood coolant
IP66/67	Strong jets / immersion	Washdown cells, sealed areas

If your shop runs flood coolant or occasional pressure-washdown, IP65 on the head is the minimum. IP54 might survive a summer and die in the first winter, one splash at a time.

Sealed IP-rated LED work light head with rubber gasket and cable gland — The seal you don't see is the one that keeps the light alive. A rated head is only as good as its cable entry.

4. Beyond the Number: The IP Reality Check

A rating is a certificate, not a behavior. The most over-rated lights in the world are the ones that claim IP67 but ship with an open seam at the switch or a glossy fake "gasket" on the lens.

Ask for the test report, not just the sticker. A real IP test takes hours and costs money; a sticker costs 5 cents.
Water is not coolant. Coolant is chemically nastier than plain water. A light that survives clean water can still corrode inside on emulsified coolant. Prefer heads with sealed, corrosion-resistant internals.
Vapor is the silent killer. Hot coolant produces vapor that condenses on a cold lens — and finds every seam. IP65 alone won't save you; an internal sealing and breathable membrane will.

"An IP rating is a promise. The cable gland is where promises go to die."

ONN · Machine Lighting

Sealed for coolant, rated for reality

Every ONN LED work light ships with a sealed cable gland, a gasketed lens and a test report you can actually read. If you run flood coolant or washdowns, ask us for the IP65+ line.

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