IP18 vs IP33
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP18 and IP33 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 1 vs 3) and liquid protection (level 8 vs 3). IP18 is rated for > 50 mm — back of hand and continuous immersion (manufacturer-specified), while IP33 provides > 2.5 mm — tool / wire and spraying water (up to 60°).
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.
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.
Detailed comparison
The stronger rating on each row is highlighted in emerald.
Solid protection (first digit)
IP18
1 — > 50 mm — Back of Hand
IP33
3 — > 2.5 mm — Tool / Wire
Liquid protection (second digit)
IP18
8 — Continuous Immersion (manufacturer-specified)
IP33
3 — Spraying Water (up to 60°)
Dust-tight
IP18
No
IP33
No
Water-jet resistant
IP18
Yes
IP33
No
Submersible
IP18
Yes
IP33
No
Outdoor suitable
IP18
Yes
IP33
No
The exact difference (IP18 vs IP33)
Solid protection
IP18
Level 1 — > 50 mm — Back of Hand
IP33
Level 3 — > 2.5 mm — Tool / Wire
IP18 provides "> 50 mm — Back of Hand" (level 1), while IP33 provides "> 2.5 mm — Tool / Wire" (level 3). IP33 is 2 levels higher.
Liquid protection
IP18
Level 8 — Continuous Immersion (manufacturer-specified)
IP33
Level 3 — Spraying Water (up to 60°)
IP18 handles Specified by manufacturer (Continuous Immersion (manufacturer-specified)), while IP33 handles 80 kPa (tube) / 50 kPa (nozzle) (Spraying Water (up to 60°)). 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.