IP44 vs IP65 vs IP67: Which Power Supply Rating Do You Need?

IP68 is a worse buying decision than IP67, and the reason is uncomfortable: IP68 has no standardised test. Under IEC 60529, IP68 means only “deeper than IP67, conditions agreed between manufacturer and user.” Each factory picks its own depth and duration. You cannot compare two suppliers’ IP68 claims. You can compare their IP67 claims exactly, because IP67 is pinned down: 30 minutes at 1 metre.

Start there, and the rest of the rating chart makes sense.

What the Two Digits Mean

First digit — solids, 0 to 6:

Second digit — liquids, 0 to 9K:

The Three Ratings Compared

The Cost Nobody Calculates: Heat

IP67 housings are sealed and usually potted. That removes the convection path air provided. Our own bench data on a 200 W design shows the internal hotspot running 8–12°C hotter in a potted housing than in a vented one at the same ambient.

Apply the capacitor rule — every 10°C halves electrolytic life — and that penalty costs you roughly half your design life if the thermal design was not adjusted to compensate.

This produces the second counter-intuitive result: specifying IP67 for an indoor sign cabinet can shorten the driver’s life. A sealed, potted unit bolted inside an unventilated light box runs hotter than an IP20 open-frame driver doing the same job. You paid 30–40% more for a unit that dies sooner.

Decision Tree

Answer three questions in order:

1. Can water pool around the unit? Yes → IP67. No → continue.
2. Will it be hosed or pressure-washed? Yes → IP65 minimum, IP66 for high pressure. No → continue.
3. Is it outdoors at all? Yes → IP65. No, and users cannot touch it → IP20 is correct and cheapest.

One more filter that overrides all of the above: can a person touch it? If yes, safety standards require an enclosed housing regardless of water exposure. That is the actual test for enclosed vs open-frame — not “indoor or outdoor.”

Where Each Rating Sits in Our Range

• IP20 indoor: N series, CPS industrial, CLL slim
• IP65 rainproof: CFX signage series, 150 W to 500 W
• IP67 waterproof: R series, 60 W to 350 W; LP Class II where no earth ground is available

Four Misconceptions

1. “Higher IP is always safer.” Not in an unventilated enclosure — see the thermal penalty above.
2. “IP67 means it can be submerged permanently.” It means 30 minutes at 1 metre in still, temperature-matched water.
3. “IP and IK are the same thing.” IP is ingress; IK (IEC 62262) is impact energy. IK08 = 5 J, IK10 = 20 J. A plastic IP67 housing can shatter at IK06. Public-realm signage needs both numbers.
4. “The rating covers the cable gland.” It covers the enclosure as tested — usually with the gland fitted to a specified cable diameter. Fit a thinner cable and you have re-engineered the seal.

Pick by installation environment, not by rating number. Send us your mounting position, drainage and wash-down frequency; we will tell you which rating you actually need. → Browse by IP rating · Read the IP67 buyer’s guide