The Electrical Panels can be mounted on the robust base frame made up of steel channel with a height of 75 mm OR 100 mm. The base frame shall be able to withstand the static and dynamic loads of the Electrical Panels.
Static Load :
A static load is time independent and has a single response. Switchboard ASSEMBLY dead weight is Static load.
Dynamic Load :
Dynamic means time variant. A load which changes in magnitude,direction and position with respect to time is called dynamic loading. The response to a dynamic loading will also be varying with time. When Switchboard ASSEMBLY is clearing or withstanding Dynamic Fault conditions like Short Circuit Fault Or Arc Flash fault, there are Dynamic Forces generated inside the ASSEMBLY and when these Forces combined with Weight of panel put Dynamic load on the Base Frame Channel.
The Base Frame steel channels shall be painted with epoxy polyester paint.
As a standard Industry practice ISMC channel is used as Base Frame for Switchboard Assembly.
ISMC : India Standard Medium Channel
ISMC channel grade is defined into IS:2062, Normally Grade A.
| ISMC Size | Height | Width | Thickness of Height |
Thickness of Width |
Weight |
|---|---|---|---|---|---|
| 75 x 40 | 75 mm | 40 mm | 4.8 mm | 7.5 mm | 7.1 Kg/m |
| 100 x 50 | 100 mm | 50 mm | 5 mm | 7.7 mm | 9.6 Kg/m |
| 150 x 75 | 150 mm | 75 mm | 5.7 mm | 9 mm | 16.8 Kg/m |
Fastening of Base Frame to the Foundation
Switchboard Assembly is Either Welded OR Bolted to the Base Frame. Switchboard Assemblies are normally mounted on the Base Frame Channel of 75 mm OR 100 mm.
These Base Frame Channels can Either be Embedded in the Foundation concrete OR it can be fixed on supports mounted on false floor.
While Installing Switchboard Assembly on site, care should be taken to ensure proper alignment and it should be ensured that Base Frame should have horizontal tolerance less than 2 mm per 1 meter panel length.