IP18 vs IP55
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP18 and IP55 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 1 vs 5) and liquid protection (level 8 vs 5). IP18 is rated for > 50 mm — back of hand and continuous immersion (manufacturer-specified), while IP55 provides dust-protected and water jets (6.3 mm nozzle).
The IP18 classification guarantees protection against solid objects larger than 50 mm and protection against the effects of continuous immersion in water under conditions specified by the manufacturer.. It is an IEC 60529 ingress protection code combining first-digit (solid) level 1 with second-digit (liquid) level 8.
IP55 is dust-protected and resists low-pressure water jets (6.3 mm nozzle, 30 kPa). A popular industrial rating for equipment exposed to dust and directed water spray but not immersion.
Detailed comparison
The stronger rating on each row is highlighted in emerald.
Solid protection (first digit)
IP18
1 — > 50 mm — Back of Hand
IP55
5 — Dust-Protected
Liquid protection (second digit)
IP18
8 — Continuous Immersion (manufacturer-specified)
IP55
5 — Water Jets (6.3 mm nozzle)
Dust-tight
IP18
No
IP55
Limited
Water-jet resistant
IP18
Yes
IP55
Yes
Submersible
IP18
Yes
IP55
No
Outdoor suitable
IP18
Yes
IP55
Yes
The exact difference (IP18 vs IP55)
Solid protection
IP18
Level 1 — > 50 mm — Back of Hand
IP55
Level 5 — Dust-Protected
IP18 provides "> 50 mm — Back of Hand" (level 1), while IP55 provides "Dust-Protected" (level 5). IP55 is 4 levels higher.
Liquid protection
IP18
Level 8 — Continuous Immersion (manufacturer-specified)
IP55
Level 5 — Water Jets (6.3 mm nozzle)
IP18 handles Specified by manufacturer (Continuous Immersion (manufacturer-specified)), while IP55 handles 30 kPa (Water Jets (6.3 mm nozzle)). IP18 provides 3 levels more liquid protection.
NEMA equivalents
No direct NEMA equivalent.
No direct NEMA equivalent.
Recommendation
IP55 offers higher overall protection than IP18. Choose IP55 for harsher environments; IP18 may suffice for milder conditions and can be more cost-effective.