Used to protect cable from outside factors which can damage cable. Common sizes of conduit include 20mm, 25mm, 40mm, 50mm, 100mm, 150 mm and over.
Conduit is rated for different uses including protection from solar degradation and heavy duty which would be used for ducting mains in an industrial scenario.
The current carrying capacity of cable changes when its located inside conduit. This needs to be taken into account when doing volt drop calculations.
Rules exist around how many cables and what type of cables are allowed together in a single conduit .
For example, standard voltage cable must not be in the same conduit as extra low voltage cable such as speaker or communications cable (ASNZS:3000:2007).
