IP40 vs IP21
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP40 and IP21 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 4 vs 2) and liquid protection (level 0 vs 1). IP40 is rated for > 1 mm — small wires and no protection, while IP21 provides > 12.5 mm — finger and vertically dripping water.
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.
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)
IP40
4 — > 1 mm — Small Wires
IP21
2 — > 12.5 mm — Finger
Liquid protection (second digit)
IP40
0 — No Protection
IP21
1 — Vertically Dripping Water
Dust-tight
IP40
No
IP21
No
Water-jet resistant
IP40
No
IP21
No
Submersible
IP40
No
IP21
No
Outdoor suitable
IP40
No
IP21
No
The exact difference (IP40 vs IP21)
Solid protection
IP40
Level 4 — > 1 mm — Small Wires
IP21
Level 2 — > 12.5 mm — Finger
IP40 provides "> 1 mm — Small Wires" (level 4), while IP21 provides "> 12.5 mm — Finger" (level 2). IP40 is 2 levels higher.
Liquid protection
IP40
Level 0 — No Protection
IP21
Level 1 — Vertically Dripping Water
IP40 provides "No Protection" (level 0), while IP21 provides "Vertically Dripping Water" (level 1). IP21 is 1 level higher.
NEMA equivalents
No direct NEMA equivalent.
Recommendation
IP40 offers higher overall protection than IP21. Choose IP40 for harsher environments; IP21 may suffice for milder conditions and can be more cost-effective.