Conduit

Still by far the most common form of containment. Conduit comprises lengths of robust tube, available in set sizes 16mm, 20mm, 25mm & 32mm. Conduit is available in both PVC and Steel form. PVC conduit is available in light & heavy duty grades and is relatively easy to install, requiring basic tools & adhesive to install. Steel conduit affords better protection than PVC but requires specialist tools and knowledge to install. It is available in Black Enamel (painted) finish or Galvanised finish (for exterior applications). Properly installed steel conduit can be used as a CPC.
Conduit can be surface mounted or buried (flush) in walls. It is used extensively with single cables and Twin & Earth (for protection down walls etc.). Flexible conduit is not a direct variant of standard conduit, it is commonly formed from spiral arrangements of toughened PVC, steel or aluminium. The construction allows the conduit to be flexed and is normally used in short lengths to serve equipment and or items that may need to be moved.

Trunking

A form of containment that having a hollow box shaped section, and available in linear lengths. Trunking is available in both PVC and steel. PVC trunking can range in size from 15x15mm up to 150x150mm or even bigger and is quick and easy to install. Steel trunking affords better protection but is harder to install. Steel trunking comes in sizes from 50x50mm up to 300x300 and above.
Trunking is particularly suitable for use with single cables where many circuits can be contained in a single trunking (subject to compliance with BS7671 segregation regulations). Twin & Earth cables can also be protected by trunking.  

Floor trunking

A form of trunking that is specially adapted for installation within floor voids, or screeds. It commonly has two or more compartments enabling segregation and hence is used for 240V services as well as data and telecommunication systems. It is often fitted with custom floorboxes. Space restrictions can mean limited room in floor trunking and the number of cables able to be installed can

Perimeter Trunking Systems

Another trunking variant, this type of trunking is manufactured in various forms, normally with two or more compartments. It can be obtained in the form of dado trunking, skirting trunking or even cornice trunking. Available in PVC, aluminium or steel (powered coated or painted) perimeter trunking systems are a popular choice in open plan office, general offices and similar areas.

Cable Tray

Cable tray is a form of steel traywork, available in linear lengths which is used in industrial and commercial situations as a support for cables which are installed in free air (such as SWA and MICC cables) Cable tray is normally available in sizes between 50mm wide and 900mm wide, in a range of gauges light, medium & heavy duty. It is usually supplied galvanised, although special finishes such as power coating are sometimes used.
In recent years, plastic based alternatives have been developed.