Choosing the right wire size for your home wiring
Wiring is hidden inside walls, so mistakes are easy to forget about until something goes wrong. Choosing the right wire size is one of the simplest ways to make a home safer.
Why size matters
A wire that is too thin for the load heats up, wastes energy and can become a fire risk. The right size depends on the load (in watts), the length of the run and how the cable is installed.
Sizes commonly used in homes
- Lighting circuits: 1.0 to 1.5 sq mm copper wire.
- Power sockets (5A / 6A): about 1.5 to 2.5 sq mm.
- Heavier sockets (15A / 16A) and ACs: about 2.5 to 4 sq mm.
- Geysers, ovens and other high loads: often 4 sq mm or more on a dedicated circuit.
These are typical ranges only. A licensed electrician should confirm the correct size for your actual loads and cable lengths.
Protect each circuit
- Use MCBs of the right rating for each circuit and an RCCB or RCBO for earth-leakage protection.
- Keep lights, sockets and heavy appliances on separate circuits.
- Run a proper earth wire to every socket.
Buying tips
- Choose ISI-marked, flame-retardant copper wire from a known brand.
- Check the coil for a printed brand name, size and length, and avoid unmarked coils.
- Use different colours for phase, neutral and earth to make future work safer.
Electrical work should always be carried out by a qualified electrician.
