When designing an electrical setup, we need to choose the right size of cables and anticipate the maximum short circuit load. To secure the cables during a short circuit, we use clamps. Each clamp type has different strengths and benefits, so we must calculate the force between the conductors during a short circuit to determine the appropriate clamp spacing.
Clamp manufacturers test their products using short circuit tests to ensure they can handle the expected loads. These tests follow a standard (IEC 61914), and the clamps must meet certain criteria without failing. The tests involve simulating a short circuit scenario and checking for any damage to the cables or clamps.
For three-phase short circuits with cables arranged in a trefoil configuration, we use a formula to calculate the maximum force on the conductor based on the peak short circuit current and the distance between the conductors.
Overall, to ensure the safety and reliability of an electrical installation, it’s crucial to select the right clamps based on the calculated forces and to adhere to testing standards like IEC 61914.
For a three phase short circuit with the cables in a trefoil configuration the maximum force on the conductor is:
To compare short circuit test results for trefoil clamps, we need to know the fault level, clamp spacing, and cable diameter. This helps us determine if a clamp can handle a specific short circuit scenario at a certain spacing for a particular cable size.