IP21 vs IP37
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP21 and IP37 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 2 vs 3) and liquid protection (level 1 vs 7). IP21 is rated for > 12.5 mm — finger and vertically dripping water, while IP37 provides > 2.5 mm — tool / wire and temporary immersion (up to 1 m).
Designed for environments requiring protection against solid objects larger than 12.5 mm and protection against vertically falling drops of water. Dripping water shall have no harmful effects., IP21 is an IEC 60529 code combining solid level 2 with liquid level 1.
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.
Detailed comparison
The stronger rating on each row is highlighted in emerald.
Solid protection (first digit)
IP21
2 — > 12.5 mm — Finger
IP37
3 — > 2.5 mm — Tool / Wire
Liquid protection (second digit)
IP21
1 — Vertically Dripping Water
IP37
7 — Temporary Immersion (up to 1 m)
Dust-tight
IP21
No
IP37
No
Water-jet resistant
IP21
No
IP37
Yes
Submersible
IP21
No
IP37
Yes
Outdoor suitable
IP21
No
IP37
Yes
The exact difference (IP21 vs IP37)
Solid protection
IP21
Level 2 — > 12.5 mm — Finger
IP37
Level 3 — > 2.5 mm — Tool / Wire
IP21 provides "> 12.5 mm — Finger" (level 2), while IP37 provides "> 2.5 mm — Tool / Wire" (level 3). IP37 is 1 level higher.
Liquid protection
IP21
Level 1 — Vertically Dripping Water
IP37
Level 7 — Temporary Immersion (up to 1 m)
IP21 handles 0.1 mm/min drip rate (Vertically Dripping Water), while IP37 handles Hydrostatic ~10 kPa at 1 m (Temporary Immersion (up to 1 m)). IP37 provides 6 levels more liquid protection.
NEMA equivalents
No direct NEMA equivalent.
Recommendation
IP37 offers higher overall protection than IP21. Choose IP37 for harsher environments; IP21 may suffice for milder conditions and can be more cost-effective.