Design of Electrical Equipment Foundation as per IS code

The foundation design for electrical equipment, such as transformers, switchgear, or other heavy machinery, must account for both normal operational loads and short-circuit (dynamic) load cases to ensure structural safety and stability

Normal Load Cases

• Dead Load (DL):
  Includes the weight of the equipment, oil (if applicable), and other static components.WDL=Wequipment+Woil+Wauxiliary​
• Live Load (LL):
  Includes any maintenance or operational live loads, such as personnel or movable equipment.
• Environmental Loads:
  • Wind Load (WL): As per IS 875 (Part 3) or ASCE 7-10/16.
  • Seismic Load (EQ): As per IS 1893 or relevant seismic design codes.

Short-Circuit Load Case

• Dynamic Forces:
  Short-circuit faults cause electromagnetic forces acting on the equipment, which must be resisted by the foundation.
  • Horizontal Load (Fsc​): Caused by the short-circuit forces transmitted through the equipment’s anchor bolts.
  • Fsc=K⋅Isc2
  •  Where:
    Isc​ = Short-circuit current (kA)
    K = Coefficient dependent on equipment and installation.
  • Overturning Moments (Msc): Result from the horizontal forces causing rotational forces at the foundation level.