Single Conductor Cables form a significant sector of the cables used in buildings, and are the cables often installed in conduits and raceways. Copper conductors are strong and compact, and there is minimal risk of stretching or breakages when being pulled through conduits. The five most common Single Conductor Cables are known as TW75 and TWU (both PVC Insulated Cables), RW90 and RWU90 (both XLPE Insulated Cables), and T90 Nylon, which is a Nylon covered PVC Insulated Cable.

TW75 and TWU have solid (Figure 1) or stranded (Figure 2) copper conductors, and a rating of 600 volts.

The applications for TW75 are exposed wiring in dry, damp and wet locations, and it may be installed in raceways, except cable trays. The applications for TWU are similar to those for TW75, with the addition of direct earth burial providing there is protection as required by the inspection authority, and for service entrance below ground in accordance with the Canadian Electrical Code.

RW90 has solid or stranded copper conductors for sizes #14 AWG to #10 AWG, with a standard rating of 600 volts. Applications for RW90 are the same as those for TW75.

RWU90, sizes #14 to #10 AWG, have solid or stranded copper conductors, while sizes #8 to 2000 kcmil, have stranded conductors and a rating of 1000 volts. The applications are the same as those for RW90, with the addition of direct earth burial providing there is protection as required by the inspection authority, and service entrance below ground.

The other common Single Conductor Cable is T90 Nylon, with solid or stranded copper conductors, and a rating of 600 volts. Applications for this cable are exposed wiring in dry or damp locations, and it may be installed in raceways, except cable trays.