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Circuit Breaker Coordination Simulator

IEEE Extremely Inverse TCC curves · Adjust trip settings · Verify selectivity

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Selective Coordination — PASS

Selective coordination achieved — downstream trips faster than upstream at all fault levels.

⚡ Fault Current

Available fault current5000 A

Shown as dashed yellow line on TCC chart

Main (Upstream)

Breaker Rating400 A

Instantaneous Trip (×In)10×

Time-Dial Multiplier (TDM)1

Rated Pickup

400 A

Inst. Trip

4,000 A

Feeder (Downstream)

Breaker Rating100 A

Instantaneous Trip (×In)8×

Time-Dial Multiplier (TDM)0.3

Rated Pickup

100 A

Inst. Trip

800 A

📊 Trip Times at Fault Current

Main (Upstream)< 0.02 s (Inst.)

Feeder (Downstream)< 0.02 s (Inst.)

IEEE / NEC Reference: Selective coordination per NEC 700.32, 701.27, and 708.54 requires the downstream device to clear faults before the upstream device operates. Minimum recommended time margin: 0.1–0.3 s (electromechanical devices).

IEEE Extremely Inverse TCC · Log-Log Scale

Main (Upstream)

Feeder (Downstream)

Fault level