IP37 vs IP51
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP37 and IP51 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 3 vs 5) and liquid protection (level 7 vs 1). IP37 is rated for > 2.5 mm — tool / wire and temporary immersion (up to 1 m), while IP51 provides dust-protected and vertically dripping water.
Specified under IEC 60529, IP37 denotes protection against solid objects larger than 2.5 mm and protection against the effects of temporary immersion in water. Ingress of water in quantities causing harmful effects shall not be possible.. It is an IEC 60529 ingress protection code combining first-digit (solid) level 3 with second-digit (liquid) level 7.
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)
IP37
3 — > 2.5 mm — Tool / Wire
IP51
5 — Dust-Protected
Liquid protection (second digit)
IP37
7 — Temporary Immersion (up to 1 m)
IP51
1 — Vertically Dripping Water
Dust-tight
IP37
No
IP51
Limited
Water-jet resistant
IP37
Yes
IP51
No
Submersible
IP37
Yes
IP51
No
Outdoor suitable
IP37
Yes
IP51
No
The exact difference (IP37 vs IP51)
Solid protection
IP37
Level 3 — > 2.5 mm — Tool / Wire
IP51
Level 5 — Dust-Protected
IP37 provides "> 2.5 mm — Tool / Wire" (level 3), while IP51 provides "Dust-Protected" (level 5). IP51 is 2 levels higher.
Liquid protection
IP37
Level 7 — Temporary Immersion (up to 1 m)
IP51
Level 1 — Vertically Dripping Water
IP37 handles Hydrostatic ~10 kPa at 1 m (Temporary Immersion (up to 1 m)), while IP51 handles 0.1 mm/min drip rate (Vertically Dripping Water). IP37 provides 6 levels more liquid protection.
NEMA equivalents
No direct NEMA equivalent.
No direct NEMA equivalent.
Recommendation
IP37 offers higher overall protection than IP51. Choose IP37 for harsher environments; IP51 may suffice for milder conditions and can be more cost-effective.