IP18 vs IP21
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP18 and IP21 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 1 vs 2) and liquid protection (level 8 vs 1). IP18 is rated for > 50 mm — back of hand and continuous immersion (manufacturer-specified), while IP21 provides > 12.5 mm — finger and vertically dripping water.
The IP18 classification guarantees protection against solid objects larger than 50 mm and protection against the effects of continuous immersion in water under conditions specified by the manufacturer.. It is an IEC 60529 ingress protection code combining first-digit (solid) level 1 with second-digit (liquid) level 8.
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.
Detailed comparison
The stronger rating on each row is highlighted in emerald.
Solid protection (first digit)
IP18
1 — > 50 mm — Back of Hand
IP21
2 — > 12.5 mm — Finger
Liquid protection (second digit)
IP18
8 — Continuous Immersion (manufacturer-specified)
IP21
1 — Vertically Dripping Water
Dust-tight
IP18
No
IP21
No
Water-jet resistant
IP18
Yes
IP21
No
Submersible
IP18
Yes
IP21
No
Outdoor suitable
IP18
Yes
IP21
No
The exact difference (IP18 vs IP21)
Solid protection
IP18
Level 1 — > 50 mm — Back of Hand
IP21
Level 2 — > 12.5 mm — Finger
IP18 provides "> 50 mm — Back of Hand" (level 1), while IP21 provides "> 12.5 mm — Finger" (level 2). IP21 is 1 level higher.
Liquid protection
IP18
Level 8 — Continuous Immersion (manufacturer-specified)
IP21
Level 1 — Vertically Dripping Water
IP18 handles Specified by manufacturer (Continuous Immersion (manufacturer-specified)), while IP21 handles 0.1 mm/min drip rate (Vertically Dripping Water). IP18 provides 7 levels more liquid protection.
NEMA equivalents
No direct NEMA equivalent.
Recommendation
IP18 offers higher overall protection than IP21. Choose IP18 for harsher environments; IP21 may suffice for milder conditions and can be more cost-effective.