IP33 vs IP51
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP33 and IP51 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 3 vs 5) and liquid protection (level 3 vs 1). IP33 is rated for > 2.5 mm — tool / wire and spraying water (up to 60°), while IP51 provides dust-protected and vertically dripping water.
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.
With IP51, an enclosure receives dust-protected (limited ingress, no harmful deposit) and protection against vertically falling drops of water. Dripping water shall have no harmful effects.. It is an IEC 60529 ingress protection code combining first-digit (solid) level 5 with second-digit (liquid) level 1.
Detailed comparison
The stronger rating on each row is highlighted in emerald.
Solid protection (first digit)
IP33
3 — > 2.5 mm — Tool / Wire
IP51
5 — Dust-Protected
Liquid protection (second digit)
IP33
3 — Spraying Water (up to 60°)
IP51
1 — Vertically Dripping Water
Dust-tight
IP33
No
IP51
Limited
Water-jet resistant
IP33
No
IP51
No
Submersible
IP33
No
IP51
No
Outdoor suitable
IP33
No
IP51
No
The exact difference (IP33 vs IP51)
Solid protection
IP33
Level 3 — > 2.5 mm — Tool / Wire
IP51
Level 5 — Dust-Protected
IP33 provides "> 2.5 mm — Tool / Wire" (level 3), while IP51 provides "Dust-Protected" (level 5). IP51 is 2 levels higher.
Liquid protection
IP33
Level 3 — Spraying Water (up to 60°)
IP51
Level 1 — Vertically Dripping Water
IP33 handles 80 kPa (tube) / 50 kPa (nozzle) (Spraying Water (up to 60°)), while IP51 handles 0.1 mm/min drip rate (Vertically Dripping Water). IP33 provides 2 levels more liquid protection.
NEMA equivalents
No direct NEMA equivalent.
No direct NEMA equivalent.
Recommendation
IP33 and IP51 offer comparable overall protection; choose based on the specific protection dimension (dust vs. water) that matters most for your application.