IP18 vs IP31
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP18 and IP31 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 1 vs 3) and liquid protection (level 8 vs 1). IP18 is rated for > 50 mm — back of hand and continuous immersion (manufacturer-specified), while IP31 provides > 2.5 mm — tool / wire 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.
The IP31 rating offers protection against solid objects larger than 2.5 mm 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 3 with second-digit (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
IP31
3 — > 2.5 mm — Tool / Wire
Liquid protection (second digit)
IP18
8 — Continuous Immersion (manufacturer-specified)
IP31
1 — Vertically Dripping Water
Dust-tight
IP18
No
IP31
No
Water-jet resistant
IP18
Yes
IP31
No
Submersible
IP18
Yes
IP31
No
Outdoor suitable
IP18
Yes
IP31
No
The exact difference (IP18 vs IP31)
Solid protection
IP18
Level 1 — > 50 mm — Back of Hand
IP31
Level 3 — > 2.5 mm — Tool / Wire
IP18 provides "> 50 mm — Back of Hand" (level 1), while IP31 provides "> 2.5 mm — Tool / Wire" (level 3). IP31 is 2 levels higher.
Liquid protection
IP18
Level 8 — Continuous Immersion (manufacturer-specified)
IP31
Level 1 — Vertically Dripping Water
IP18 handles Specified by manufacturer (Continuous Immersion (manufacturer-specified)), while IP31 handles 0.1 mm/min drip rate (Vertically Dripping Water). IP18 provides 7 levels more liquid protection.
NEMA equivalents
No direct NEMA equivalent.
No direct NEMA equivalent.
Recommendation
IP18 offers higher overall protection than IP31. Choose IP18 for harsher environments; IP31 may suffice for milder conditions and can be more cost-effective.