House wiring guide: cable sizes, protection and safety grades

Typically 1.0–1.5 sq mm for lighting and fan circuits, 2.5 sq mm for general power sockets, 4.0 sq mm for air conditioners and geysers, and 6 sq mm and above for submains. Size from the actual connected load and run length, not habit.

FR is flame retardant. FRLS adds low smoke. ZHFR is zero halogen — no corrosive gas at all. In a house fire, smoke and gas harm people before flame does. The cost difference across an entire home is small; specify FRLS as a minimum.

The MCB protects the cable, so it must be sized to the cable, not the appliance. Add RCCB or RCBO protection on socket and wet-area circuits — this is what prevents electrocution, and an MCB does not do it.

A proper earth pit with a measured earth resistance, and a continuous earth conductor to every point. Use conduit heavy enough to survive being cast into a slab, and leave draw wires so future rewiring does not mean breaking walls.

Size cables from load, specify FRLS or better, protect with correctly sized MCBs plus RCCB, and earth properly.

Compare live supplier rates or read the material category guides.

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