Switch (Panel) Boards

Switch (Panel) Boards Points : switch (panel) boards, rising mains The L.T Switch (Panel) Boards shall be factory fabricated and of the approved manufacturer. The switch board shall be fixed such that there shall be a clear space of either less than 230 mm or more than 762 mm in width behind the switch board measured from the farthest outstanding part of any attachment of conductor and more than 1000 mm in width in front of the switch board. There shall be a passage way from either end, both in front of or behind the switch board, clear to a height of at least 1829 mm.

No apparatus shall project beyond and edge of the panel. No switch body shall be mounted within 25 mm of any edge of the panel and no holes, either than meant for fixing the panel shall be drilled within 13 mm of the edge of the panel. The various live parts shall be effectively screened by barriers of non-hygroscopic, non-inflammable insulating material or shall be so spaced that an arc cannot be maintained between such parts and earth. All items of switch gears shall be readily accessible and all connections, including those to instruments and apparatus, easily traceable. The switch shall be as arranged that fuses are not “alive” when the switch is in the “Off’ position. No fuse other than those in instruments circuit shall be fixed at the back or behind a switch board, panel or frame.

The switch board shall be painted both inside and outside with one coat of antirust paint and two coats of approved synthetic enamel paint by spraying before erection. When a board is connected to voltage higher than 250 V, all the terminals or leads of apparatus mounted on it shall be marked in the following colours to indicate the different poles or phases to which the apparatus or its different terminals may have been connected.

Alternating Current—Three phases-Red, Yellow and Blue
Neutral—Black
Direct Current—Two outer wire-Red and Blue

When there are some more than one switch gear on a switch board or more than one main switchboard in the building, each switch gear shall be marked permanently and clearly indicating the section of the installation controlled by it as directed by Engineer Incharge. The main switch shall be marked as such permanently. A Danger Notice Plate shall be provided on L T Switch Panel.

There shall be a booklet having internal wiring diagram showing details of the connections to facilitate in the maintenance. The grouting of the L T Switch Panel should be carried out as per direction of the Engineering Incharge considering the situation of the site. RISING MAINS “Totally enclosed rising mains are with aluminum busbars in suitable sections which are connected to make 8 vertical run. Each section is provided with a number of wall straps for fixing the rising mains to the wall. The trunking consists of side channels of 14 SWG MS sheet and front and rear covers of 16 SWG to form to totally enclosed metal clad construction.

The bus-bars are of rectangular section of wrought aluminum with a current density not exceeding 800 Amps per square inch and are individually insulated with an non-deteriorating insulating material so as to prevent any possibility of electrical fault due to presence of vermin. The aluminum busbars conform to I.S. 5082-1969 grade 9-1 EQP. The total run is sectionalized and each section is fitted with a thrust pad to prevent the busbars from sliding downwards. Each section also has an expansion joint to take up expansion of that section.

Connections between each length are adequately insulated and the casing is provided with earth links between each length to provide earth continuity throughout the run of the rising mains. Solid risers are provided wherever required for tap-off arrangements and are suitable connected to the outgoing Tap-off boxes. A blank-end cover closes the top end of the rising main and it is possible to extend the mains easily at a later stage if desired.

Wherever the rising mains pass through a floor, a fire proof barrier is provided. The sheet steel parts used in manufacture undergo a rigorous rust proofing process and receive two coats of filler oxide primer before painting. The rising mains are subjected to a high voltage test of 2.5 KV for one minute between each phase and between each phase and neutral.

The fixing of the rising main will be done by fixing the suitable size of angle iron bracket of 50 mm x 50 mm x 6 mm size angle iron duly painted with synthetic enamel paint to match the colour of rising main. The grouting of the angle iron bracket will be done as to with hold the total load of the rising main and sliding of the same downward.