Thermoplastic-sheathed cable

The type of thermoplastic, the dimensions of the conductors and the colour of their individual insulation (if any) are specified by the regulatory bodies in the various countries concerned.

The following are nominal current ratings for copper conductors; long runs may require thicker wires to minimize voltage drop.

The outer jacket is labeled with letters that show how many insulated wires are concealed within the sheath.

Wire sizes of 1–6 mm2 cross-sectional area (CSA) are available with the outer sheath covering the cores.

The earth conductor is always stranded (unlike North American usage), with the exception of 1 mm2 cables, and covered with green-yellow striped plastic insulation.

[7][8] Flat TPS is more common than circular, and is used for fixed wiring of domestic and industrial lighting, power outlets, appliances, and HVAC units.

Mainland UK wiring regulations do not at present (BS 7671:AMD3) acknowledge twin and earth or flat TPS with a full sized and insulated (G/Y) earth conductor as a valid cable type, which may be awkward for contractors who work cross-border with the Republic of Ireland.

201 part 4: PVC and Low Smoke Halogen Free Sheathed cables for fixed wiring) permitted both the UK style of twin and earth, and also a version with a CPC with a cross-section equal to that of the main conductors and insulated in green and yellow inside the full length of the cable.

However, from 2013, the option for the uninsulated and reduced CPC has been removed from the standard IS 201-4:2013, and as such is no longer permitted in new installations in the Republic of Ireland.