Twin and Earth Cable

Twin and earth cable comprises two individually insulated current carrying conductors and an uninsulated circuit protective conductor. Twin and Earth cable is the most common cable used for domestic wiring today.
The sheath is either grey (PVC) or white for low smoke cables (OHLS).

Flat Twin and Earth

Also known as FTE (flat twin and earth) the live and neutral conductors are individually insulated, and the Circuit Protective Conductor (CPC) or earth, is bare. Not suitable for unprotected use outside as the outer sheath materials are vulnerable to attack by UV although protective paint can provide some UV protection.
Standard metric twin and earth cable sizes are:

• 1mm² 1.5mm² & 2.5mm² which have solid (non-stranded) conductors
• 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors
• 1.5mm² is used typically for domestic wiring circuits and 2.5mm² twin and earth is used in domestic power circuits