What is Short Circuit Withstand (ICW)? Short Circuit Protection in Electrical Panels.
Short circuit resistance:
ContentsShort-circuit withstand capability is the ability of an electrical panel to withstand high currents and mechanical forces generated during a short circuit without damage. It is one of the most critical performance values of the panel in terms of life and property safety.
ICW and IPK Values
- Icw (rated short-circuit withstand current): This is the effective short-circuit current (in kA) that the panel can withstand for a specific period of time (usually 1 second).
- Ipk (rated peak withstand current): This is the peak current at the initial moment of a short circuit; it determines the electromagnetic forces acting on the busbars.
Why are short circuits dangerous?
During a short circuit, the current can increase to tens of times the normal operating values. This creates both thermal and dynamic stress. A switchboard with insufficient structural integrity can lead to deformation of the busbars, internal combustion, and fire.
How to determine the correct ICW value?
The Icw value should be calculated based on the power of the facility’s supply transformer and the short-circuit level of the grid. The panel should have an Icw value higher than the maximum short-circuit current that may occur in the facility. Devpan panels are designed with Icw values that comply with project short-circuit calculations; for details, please refer to the low-voltage panels page.
Frequently Asked Questions
What is short-circuit withstand capability?
Short-circuit withstand capability is the ability of a switchboard to withstand high currents and mechanical forces generated during a short circuit without being damaged.
What is the difference between ICW and IPK?
Icw represents the effective short-circuit current that can be withstood for a certain period, while Ipk represents the peak current at the initial moment of the short circuit.
How do you select the ICW value for the panel?
The Icw value is calculated based on the power of the supply transformer in the facility and the grid short-circuit level, and must be higher than the maximum short-circuit current that may occur.
Key takeaways: short circuit resistance
- Why are short circuits dangerous — During a short circuit, the current can increase to tens of times the normal operating values.
- How to determine the correct ICW value — The Icw value should be calculated based on the power of the facility’s supply transformer and the short-circuit level of the grid.
- Standard source — IEC publication catalogue: iec.ch.
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- Short Circuit Withstand in Switchboards: Icw, Ipk and Conditional Rating
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Related Devpan solution: electrical panel design services.
