circuit breaker selection work package

Product: Circuit Breaker Role: Electrical Engineer

Engineering Purpose

To select the appropriate circuit breaker(s) that safely and reliably protect a specific electrical distribution system under normal, overload, and fault conditions while meeting coordination, performance, and compliance requirements.

This verification tool coordinates the 4 required engineering checks and produces an overall engineering acceptance decision.

Verification Inputs

Enter the measured and reference values for each required check. All fields correspond to the bound small tool input contracts.

1 Switchgear Required Rated Current with User-Supplied Derating Factors Calculation

Calculate continuous current rating (In) considering ambient temperature and installation arrangement derating

Continuous load current (A)

Temperature derating Kt

Enclosure derating Ke

Installation derating Ki

2 Circuit Breaker Trip Unit Setting Constraint Verifier Verification

Select trip unit type and settings to satisfy instantaneous and long-time overcurrent protection requirements

Required Rated Current (A) (auto)

Breaker rated current In (A)

Conductor ampacity (A)

Peak inrush current (A)

Max coordination time (s)

Long-time pickup Ir (A)

Long-time delay tr (s)

Short-time pickup Isd (A)

Short-time delay tsd (s)

Instantaneous pickup Ii (A)

Device Ir min (A)

Device Ir max (A)

Device Isd min (A)

Device Isd max (A)

Device Ii min (A)

Device Ii max (A)

3 Common-Point TCC Coordination Margin Evaluator Verification

Verify time-current coordination margin between downstream fuse and upstream circuit breaker

Common-point TCC dataset (array)

Min coordination margin (s)

4 Circuit Breaker Short-Circuit Rating Requirement Verifier Verification

Convert manufacturer-provided Ics rating to equivalent service short-time current (Icw) for 1-second duty per IEC 62271-100

Available fault current (kA)

Required Ics min (kA)

Required Icw min (kA)

Required withstand duration (s)

Manufacturer Icu (kA)

Manufacturer Ics (kA)

Manufacturer Icw (kA)

Manufacturer Icw duration (s)

Verification Results

Switchgear Required Rated Current with User-Supplied Derating FactorsPending

Circuit Breaker Trip Unit Setting Constraint VerifierPending

Common-Point TCC Coordination Margin EvaluatorPending

Circuit Breaker Short-Circuit Rating Requirement VerifierPending

Overall Project Decision

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