Pick the wire size from the load it has to carry. The sizes below assume 230 V single phase, copper conductor and reasonably short runs. For long cable runs, go one size up to keep voltage drop within 3% (see the voltage-drop table).
| Circuit / appliance | Typical load | Recommended copper wire |
|---|---|---|
| Lighting & fan circuit | up to ~0.8 kW | 1.0 – 1.5 sq mm |
| 5 A socket circuit | up to ~1 kW | 1.5 sq mm |
| 15 / 16 A power socket | up to ~3 kW | 2.5 sq mm |
| Geyser / water heater | 2 – 3 kW | 2.5 – 4 sq mm |
| Air conditioner (1 – 1.5 ton) | ~1.5 – 2.2 kW | 2.5 – 4 sq mm |
| Air conditioner (2 ton) | ~2.5 – 3 kW | 4 sq mm |
| Kitchen (microwave, oven, hob) | 3 – 5 kW | 4 sq mm |
| Sub-main to distribution board | — | 6 – 10 sq mm |
| Incoming mains (per load) | — | 10 – 16 sq mm |
Tip: Choose a fire-safe grade for the wire itself, not just the right size. For homes, an HR-FR-LSH or HFFR wire (low smoke, halogen-free) is far safer in a fire than ordinary PVC.