IP33 vs IP18
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP33 and IP18 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 3 vs 1) and liquid protection (level 3 vs 8). IP33 is rated for > 2.5 mm — tool / wire and spraying water (up to 60°), while IP18 provides > 50 mm — back of hand and continuous immersion (manufacturer-specified).
IP33 protects against tools and 2.5 mm objects plus spraying water up to 60° from vertical. A practical rating for indoor equipment subject to light spray or for sheltered outdoor fixtures.
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.
Detailed comparison
The stronger rating on each row is highlighted in emerald.
Solid protection (first digit)
IP33
3 — > 2.5 mm — Tool / Wire
IP18
1 — > 50 mm — Back of Hand
Liquid protection (second digit)
IP33
3 — Spraying Water (up to 60°)
IP18
8 — Continuous Immersion (manufacturer-specified)
Dust-tight
IP33
No
IP18
No
Water-jet resistant
IP33
No
IP18
Yes
Submersible
IP33
No
IP18
Yes
Outdoor suitable
IP33
No
IP18
Yes
The exact difference (IP33 vs IP18)
Solid protection
IP33
Level 3 — > 2.5 mm — Tool / Wire
IP18
Level 1 — > 50 mm — Back of Hand
IP33 provides "> 2.5 mm — Tool / Wire" (level 3), while IP18 provides "> 50 mm — Back of Hand" (level 1). IP33 is 2 levels higher.
Liquid protection
IP33
Level 3 — Spraying Water (up to 60°)
IP18
Level 8 — Continuous Immersion (manufacturer-specified)
IP33 handles 80 kPa (tube) / 50 kPa (nozzle) (Spraying Water (up to 60°)), while IP18 handles Specified by manufacturer (Continuous Immersion (manufacturer-specified)). IP18 provides 5 levels more liquid protection.
NEMA equivalents
No direct NEMA equivalent.
No direct NEMA equivalent.
Recommendation
IP18 offers higher overall protection than IP33. Choose IP18 for harsher environments; IP33 may suffice for milder conditions and can be more cost-effective.