IP39K vs IP66
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP39K and IP66 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 3 vs 6) and liquid protection (level 9K vs 6). IP39K is rated for > 2.5 mm — tool / wire and high-pressure, high-temp water jets, while IP66 provides dust-tight and powerful water jets (12.5 mm nozzle).
IP39K is an ingress protection code that ensures protection against solid objects larger than 2.5 mm and resistance to high-pressure (8–10 MPa), high-temperature (80 °C) water jets. It is an IEC 60529 ingress protection code combining first-digit (solid) level 3 with second-digit (liquid) level 9K.
IP66 is dust-tight and resists powerful water jets (12.5 mm nozzle, 100 kPa). A robust outdoor rating for equipment exposed to heavy rain, storms, or directed high-pressure hosing (but not high-pressure washdown).
Detailed comparison
The stronger rating on each row is highlighted in emerald.
Solid protection (first digit)
IP39K
3 — > 2.5 mm — Tool / Wire
IP66
6 — Dust-Tight
Liquid protection (second digit)
IP39K
9 — High-Pressure, High-Temp Water Jets
IP66
6 — Powerful Water Jets (12.5 mm nozzle)
Dust-tight
IP39K
No
IP66
Yes
Water-jet resistant
IP39K
Yes
IP66
Yes
Submersible
IP39K
Yes
IP66
No
Outdoor suitable
IP39K
Yes
IP66
Yes
The exact difference (IP39K vs IP66)
Solid protection
IP39K
Level 3 — > 2.5 mm — Tool / Wire
IP66
Level 6 — Dust-Tight
IP39K provides "> 2.5 mm — Tool / Wire" (level 3), while IP66 provides "Dust-Tight" (level 6). IP66 is 3 levels higher.
Liquid protection
IP39K
Level 9 — High-Pressure, High-Temp Water Jets
IP66
Level 6 — Powerful Water Jets (12.5 mm nozzle)
IP39K handles 8–10 MPa (High-Pressure, High-Temp Water Jets), while IP66 handles 100 kPa (Powerful Water Jets (12.5 mm nozzle)). IP39K provides 3 levels more liquid protection.
NEMA equivalents
No direct NEMA equivalent.
Recommendation
IP39K and IP66 offer comparable overall protection; choose based on the specific protection dimension (dust vs. water) that matters most for your application.