IP42 vs IP51
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP42 and IP51 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 4 vs 5) and liquid protection (level 2 vs 1). IP42 is rated for > 1 mm — small wires and dripping water at 15° tilt, while IP51 provides dust-protected and vertically dripping water.
With IP42, an enclosure receives protection against solid objects larger than 1.0 mm and protection against vertically falling drops of water when the enclosure is tilted up to 15° from its normal position.. It is an IEC 60529 ingress protection code combining first-digit (solid) level 4 with second-digit (liquid) level 2.
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)
IP42
4 — > 1 mm — Small Wires
IP51
5 — Dust-Protected
Liquid protection (second digit)
IP42
2 — Dripping Water at 15° Tilt
IP51
1 — Vertically Dripping Water
Dust-tight
IP42
No
IP51
Limited
Water-jet resistant
IP42
No
IP51
No
Submersible
IP42
No
IP51
No
Outdoor suitable
IP42
No
IP51
No
The exact difference (IP42 vs IP51)
Solid protection
IP42
Level 4 — > 1 mm — Small Wires
IP51
Level 5 — Dust-Protected
IP42 provides "> 1 mm — Small Wires" (level 4), while IP51 provides "Dust-Protected" (level 5). IP51 is 1 level higher.
Liquid protection
IP42
Level 2 — Dripping Water at 15° Tilt
IP51
Level 1 — Vertically Dripping Water
IP42 handles 0.3 mm/min drip rate (Dripping Water at 15° Tilt), while IP51 handles 0.1 mm/min drip rate (Vertically Dripping Water). IP42 provides 1 level more liquid protection.
NEMA equivalents
No direct NEMA equivalent.
No direct NEMA equivalent.
Recommendation
IP42 and IP51 offer comparable overall protection; choose based on the specific protection dimension (dust vs. water) that matters most for your application.