Continuity of Conduit Wiring

Continuity of Conduit Wiring Points : continuity of conduit wiring As mentioned in the Section on Earthing, it is recommended that a bare copper wire be run alongside the conduit as the earth continuity conductor. This is to make all the metal work of the system electrically continuous and so provide a good low resistance path for any fault current that might occur. Running this separate earth conductor however, does not mean that the continuity of the conduit should not be good. If all joints are clean and tight and any bare metal painted to prevent corrosion, this provides good protection for the cables against frames and moisture as well as an additional earth path should the copper wire become disconnected for some reason.

Depending on the type of installation and the time available, conduit can be either prepared and assembled on site or prefabricated elsewhere and then brought to the site and installed. If there is a number of identical conduit runs, it is often cheaper and quicker to assemble these in batches in a workshop or somewhere convenient, rather than treat them individually on site.

Although manufactured bends are available it is generally better to bend the conduit by hand or on a machine as the result presents a good appearance and exactly the right angle can be achieved. Conduit up to I in. diameter can be bent on a simple wooden bending block as is commonly used by electricians, whereas conduit over I in diameter should be bent with the aid of a bending machine. Conduit should be cut with a hack-saw in preference to a pipe cutter, as this tends to cause a burr inside the conduit. After cutting, the ends of the conduit must be carefully filed inside and out, so that no sharp edges or burrs are left. What can happen to cables drawn into conduit if this is neglected or forgotten.

Most smaller sizes of conduit can be threaded by hand with a stock and die while held in special pipe vice.