GlossaryElectricalCable size
Cable size
Wiring · Also: Cable cross-section, 2.5mm², Wire size
In short
The conductor thickness in mm² — bigger circuits need thicker cable.
Notes
Cable size is quoted in square millimetres (for example 1.5 mm² lighting, 2.5 mm² sockets). Thicker cable carries more current safely.
The electrician matches cable size to load and breaker. Undersized cable is a fire risk; do not DIY “upgrade” breakers alone.