Calculation | Sccr

Suppose we have a 3-phase electrical system with a line-to-line voltage of 480V, a system impedance of 0.1 ohms, and an apparent power of 1 MVA. Using the formula above, we can calculate the SCCR as follows:

| Component | Marked SCCR | Current-limiting upstream? | Final SCCR contribution | |-----------|-------------|----------------------------|--------------------------| | Main Class J fuse (200 kA) | 200 kA | N/A | 200 kA | | Contactor (5 kA) | 5 kA | Yes (fuse, Table SB4.2) | 200 kA | | Overload relay (5 kA) | 5 kA | Yes | 200 kA | | Terminal block (10 kA) | 10 kA | Yes | 200 kA | sccr calculation