IP27 vs IP66
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP27 and IP66 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 2 vs 6) and liquid protection (level 7 vs 6). IP27 is rated for > 12.5 mm — finger and temporary immersion (up to 1 m), while IP66 provides dust-tight and powerful water jets (12.5 mm nozzle).
The IP27 classification guarantees protection against solid objects larger than 12.5 mm and protection against the effects of temporary immersion in water. Ingress of water in quantities causing harmful effects shall not be possible.. It is an IEC 60529 ingress protection code combining first-digit (solid) level 2 with second-digit (liquid) level 7.
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)
IP27
2 — > 12.5 mm — Finger
IP66
6 — Dust-Tight
Liquid protection (second digit)
IP27
7 — Temporary Immersion (up to 1 m)
IP66
6 — Powerful Water Jets (12.5 mm nozzle)
Dust-tight
IP27
No
IP66
Yes
Water-jet resistant
IP27
Yes
IP66
Yes
Submersible
IP27
Yes
IP66
No
Outdoor suitable
IP27
Yes
IP66
Yes
The exact difference (IP27 vs IP66)
Solid protection
IP27
Level 2 — > 12.5 mm — Finger
IP66
Level 6 — Dust-Tight
IP27 provides "> 12.5 mm — Finger" (level 2), while IP66 provides "Dust-Tight" (level 6). IP66 is 4 levels higher.
Liquid protection
IP27
Level 7 — Temporary Immersion (up to 1 m)
IP66
Level 6 — Powerful Water Jets (12.5 mm nozzle)
IP27 handles Hydrostatic ~10 kPa at 1 m (Temporary Immersion (up to 1 m)), while IP66 handles 100 kPa (Powerful Water Jets (12.5 mm nozzle)). IP27 provides 1 level more liquid protection.
NEMA equivalents
No direct NEMA equivalent.
Recommendation
IP66 offers higher overall protection than IP27. Choose IP66 for harsher environments; IP27 may suffice for milder conditions and can be more cost-effective.