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IP codesWhat do the two digits of an IP code mean?
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IP = International Protection (often called "ingress protection"). There are two numbers:
- The 1st number is protection against solid objects: fingers, tools and dust.
- The 2nd number is protection against water.
- X means "not tested / not relevant" for that part.
| 1st | Solids |
|---|---|
| 0 | Not protected |
| 1 | Objects ≥ 50 mm (back of hand) |
| 2 | Objects ≥ 12.5 mm (finger) |
| 3 | Objects ≥ 2.5 mm (tools) |
| 4 | Objects ≥ 1.0 mm (wire) |
| 5 | Dust protected |
| 6 | Dust tight |
| 2nd | Water |
|---|---|
| 0 | Not protected |
| 1 | Vertically dripping |
| 2 | Dripping, tilted up to 15° |
| 3 | Spraying |
| 4 | Splashing from any direction |
| 5 | Water jets |
| 6 | Powerful jets |
| 7 | Temporary immersion |
| 8 | Continuous immersion |
- IPX4 = splash-proof (the bathroom zone 1 minimum). IP2X = you can't poke a finger in. IP4X = you can't poke a 1 mm wire in. Consumer units use IP2X and IP4X in places, which is covered in the 18th Edition.
- IP66 = dust tight and protected against powerful jets. It's a common rating on outdoor socket enclosures, which cost about £10 compared with about £2 for an indoor socket, so you only fit one where it's needed. The Electrician's Guide (5.7.4, p.97) asks for outdoor sockets to be weather resistant (for example, IP54).
- An extra letter can follow, e.g. IPXXB (a finger can't reach live parts) or IPXXD (a 1 mm wire 100 mm long can't reach them).
On-Site Guide · Appendix L · IP codes (only about a page) Code of Practice for In-service Inspection & Testing · Appendix 2 · IP codes table · p.95 The clearest IP table — but you can't take that book into the Building Regs exam
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- 18th Edition
- Building Regs
- PAT
- Fundamental Inspection & Testing
- Initial Verification
- Periodic Inspection & Testing