IP21 vs IP51
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP21 and IP51 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 2 vs 5). IP21 is rated for > 12.5 mm — finger and vertically dripping water, while IP51 provides dust-protected and vertically dripping water.
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.
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)
IP21
2 — > 12.5 mm — Finger
IP51
5 — Dust-Protected
Liquid protection (second digit)
IP21
1 — Vertically Dripping Water
IP51
1 — Vertically Dripping Water
Dust-tight
IP21
No
IP51
Limited
Water-jet resistant
IP21
No
IP51
No
Submersible
IP21
No
IP51
No
Outdoor suitable
IP21
No
IP51
No
The exact difference (IP21 vs IP51)
Solid protection
IP21
Level 2 — > 12.5 mm — Finger
IP51
Level 5 — Dust-Protected
IP21 provides "> 12.5 mm — Finger" (level 2), while IP51 provides "Dust-Protected" (level 5). IP51 is 3 levels higher.
Liquid protection
IP21
Level 1 — Vertically Dripping Water
IP51
Level 1 — Vertically Dripping Water
Both IP21 and IP51 share the same liquid protection: Vertically Dripping Water.
NEMA equivalents
No direct NEMA equivalent.
Recommendation
IP51 offers higher overall protection than IP21. Choose IP51 for harsher environments; IP21 may suffice for milder conditions and can be more cost-effective.