IP40 vs IP18
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP40 and IP18 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 4 vs 1) and liquid protection (level 0 vs 8). IP40 is rated for > 1 mm — small wires and no protection, while IP18 provides > 50 mm — back of hand and continuous immersion (manufacturer-specified).
IP40 protects against small tools and wires (1 mm objects) but offers no water protection. Useful for indoor equipment needing finer ingress protection against small debris and tools.
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.
Detailed comparison
The stronger rating on each row is highlighted in emerald.
Solid protection (first digit)
IP40
4 — > 1 mm — Small Wires
IP18
1 — > 50 mm — Back of Hand
Liquid protection (second digit)
IP40
0 — No Protection
IP18
8 — Continuous Immersion (manufacturer-specified)
Dust-tight
IP40
No
IP18
No
Water-jet resistant
IP40
No
IP18
Yes
Submersible
IP40
No
IP18
Yes
Outdoor suitable
IP40
No
IP18
Yes
The exact difference (IP40 vs IP18)
Solid protection
IP40
Level 4 — > 1 mm — Small Wires
IP18
Level 1 — > 50 mm — Back of Hand
IP40 provides "> 1 mm — Small Wires" (level 4), while IP18 provides "> 50 mm — Back of Hand" (level 1). IP40 is 3 levels higher.
Liquid protection
IP40
Level 0 — No Protection
IP18
Level 8 — Continuous Immersion (manufacturer-specified)
IP40 provides "No Protection" (level 0), while IP18 provides "Continuous Immersion (manufacturer-specified)" (level 8). IP18 is 8 levels higher.
NEMA equivalents
No direct NEMA equivalent.
No direct NEMA equivalent.
Recommendation
IP18 offers higher overall protection than IP40. Choose IP18 for harsher environments; IP40 may suffice for milder conditions and can be more cost-effective.