Protection, Fault & Earthing
Circuit Breaker Rating Checks
Compare the entered Ib, In, Iz and prospective-fault/device-interrupt-capacity values as separate arithmetic checks without selecting a device or claiming compliance.
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Review protection and earthing calculations using entered device data, fault levels, conductor properties, test measurements and soil assumptions. These checks expose margins and modeled values for design review; they do not replace device coordination data, testing procedures or professional verification.
Protection, Fault & Earthing
Breaker Selectivity Limit Check
Compare a downstream prospective fault current with a manufacturer-published selectivity limit for one exact protective-device pair.
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Cable Short-Circuit Withstand Calculator
Calculate required conductor area and withstand current from fault current, clearing time and an entered k coefficient.
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Protective Conductor Adiabatic Check
Calculate the minimum protective-conductor area, selected-conductor withstand and I²t duty from user-provided fault current, clearing time and k coefficient.
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Earth Fault Loop Impedance Estimate
Estimate line-to-earth loop impedance, temperature-adjusted conductor resistance and fault current from user-entered source and conductor data.
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Single Earth Rod Resistance Estimate
Estimate the resistance of a single vertical rod in uniform soil using the modified Dwight long-rod approximation and user-entered soil resistivity.
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Maximum Earth Fault Loop Length by Protective Device
Convert a required fault current into a maximum loop impedance and route length using entered source and conductor data.
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Neutral Conductor Size with Harmonic Loading
Estimate neutral RMS duty from fundamental imbalance and aligned third-harmonic current, then compare it with corrected neutral capacity.
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Three-Phase Neutral Current and Third Harmonics
Estimate modeled neutral RMS current from fundamental phase-current imbalance and aligned triplen (third-harmonic) phase currents.
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Prospective Fault Current at Point of Supply
Estimate the fault current at the end of a source and cable path using source fault level and entered cable impedance.
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Protective Earth Size from Active Conductor and Fault Duty
Combine a user-entered active-to-earth sizing ratio with an adiabatic fault-duty minimum for a protective conductor.
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RCD and RCBO Trip Test Checker
Compare a measured RCD/RCBO trip current and time with an entered test multiplier and maximum time.
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