Overhead Bus-Bar System

Overhead Bus-Bar System Points : Overhead Bus-Bar System The Bus-Bar system can he used for 3-phase distribution of electricity in factories. This 3-phase supply is provided to electric machines. The bus-Bars are made of aluminum or copper material. These bus-bars are mounted on insulators and enclosed in standard lengths of steel trunking. The bus-bars are arranged in this way, by using bolts, thus forming a continuous bus-bar along the entire length of factory or workshop. At the intervals of every 1 meter, a lap-off point is provided on the bus-bars. At these points tap-off units are fitted. The tap-off unit is consists of three fuses which are mounted in a sheet case with a hinged door.

The units are provided with contact fingers, which are designed in this way that they are easily fitted on to the bus-bars. From these tap-off units, the connections are made for motors, welders plant etc; by using flexible P.V.C sheathed cables. The heavy main bus-bars are very near to loads, therefore the cost of wiring Circuit is reduced and the voltage drop are also minimized in this way. If we want to provide a supply to large number of small machines then it is a practice to fit a distribution board near the trunking system and to protect with a tap-off box fitted with fuses of suitable capacity. An earth- continuity conductor is run with trunking and mounted with earthing terminal.