Choosing the right cable size for house wiring
Draft for review. This guide is placeholder wording that the shop has not yet approved. It will be updated before launch.
Cable thickness is measured as the cross-section of the copper in square millimetres, written as 1.5mm, 2.5mm and so on. A thicker cable carries more current safely. Using a cable that is too thin makes it hot and is a fire risk.
Common choices
| Use | Typical cable |
|---|---|
| Lighting circuits | 1.5mm |
| Socket circuits | 2.5mm |
| Cooker | 6mm |
| Electric shower | 6mm to 10mm, depending on the shower rating |
| Main supply to a consumer unit | 10mm or thicker, depending on the load |
The right size also depends on how long the cable run is, how it is installed and the breaker protecting it.
Match the breaker to the cable
A breaker protects the cable, so never fit a breaker bigger than the cable can carry. Ask your electrician to match them.
Get it checked
This is general information only. Have your wiring designed or checked by a licensed electrician. If you are not sure, send us your list and we will help you with what to buy.
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