As a general guide, higher-load appliances like air conditioners and geysers usually need a larger conductor (commonly in the 2.5–4 sq mm range), while lights and fans often use 1–1.5 sq mm. The correct size always depends on the appliance load, the cable run length and your home’s wiring. For safety and compliance, have a licensed electrician size the wiring to the applicable standards rather than relying on a general rule.
