Building wire is single-core PVC insulated cable pulled into conduit for fixed wiring — the cable that runs inside walls, ceilings and risers to feed lighting points, socket circuits and distribution boards. This range is RR Kabel stock, from 1.0mm² up to 120mm², plus green/yellow earth wire.
What does mm² actually mean?
The mm² figure is the cross-sectional area of the copper conductor, not the diameter of the finished cable. More copper means lower resistance, less heat and more current the cable can safely carry. Single-core means one conductor inside one sheath, so a circuit is built from separate wires pulled into the same conduit. The small cross-sections generally serve lighting and control circuits, mid sizes serve socket and appliance circuits, and the large sizes are for submains and incoming runs.
How do I choose the right size?
Four things drive it: the load in amps, the length of the run (voltage drop grows with distance), the installation method (cable bunched in conduit runs hotter than cable clipped in free air), and ambient temperature — heat derates a cable's current-carrying capacity. Final sizing must be confirmed by a qualified electrician against the actual circuit and its protective device.
Why is earth wire green and yellow?
Colour tells anyone working on the installation later what each conductor does, and green/yellow is reserved for earthing — never used as a live or neutral. Order it in the size specified for the circuit, and take the whole run in one length: joining building wire inside conduit is poor practice.
