Conduit installations

A conduit is a tube, channei or pipe in which insuiated conductors are contained. The conduit, in effect, repiaces the PVC outer sheath of a cable, providing mechanicai protection for the insuiated conductors. A conduit instaiiation can be rewired easiiy or aitered at any time, and this flexibility, coupled with mechanical protection, makes conduit installations popular for commercial and industrial applications. There are three types of conduit used in electrical installation work steel, PVC and flexible. 

A PVC conduit installation would be suitable for the following type of installation ... 

Lighting circuits are usually wired in 1.0 or 1.5 mm cable using either a loop-in or joint-box method of installation. The loop-in method is universally employed with conduit installations or when access from above or below is prohibited after installation, as is the case with some industrial installations or blocks of flats. In this method the only joints are at the switches or lighting points, the live conductors being looped from switch to switch and the neutrals from one lighting point to another. 

Lighting circuits are usually wired in 1.0 or 1.5 mm cable using either a loop-in or joint-box method of installation. The loop-in method is universally employed with conduit installations or when access from above... 

PVC insulated cables are usually drawn into an erected conduit installation or laid into an erected trunking installation. Table 5D of the On Site Guide only gives factors for conduits up to 32 mm in diameter, which would indicate that conduits larger than this are not in frequent or common use. Where a cable enclosure greater than 32 mm is required because of the number or size of the conductors, it is generally more economical and convenient to use trunking. 

Trenching should be used to join sections of conduits installed by the directional boring method. Trenching to join conduits shall be at the contractor s expense and should be included in the unit rate... 

In a study conducted in Denver by Lowery et. al. (2000), workers who build elevators and conduits, install glass, metal, or steel were at particularly high risk of injury. A glance of the following Table shows that general labourer/casual workers ranked highest, with a total of 26 cases, followed by electrical technicians. 

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