ElecTrain

Capacitor Hazard Calculator

System inputs

Enter the voltage across the entire capacitor bank. AC voltage is treated as RMS and converted to peak using √2, following the workbook.

Estimated results

Capacitor-bank helper

Identical capacitors only, connected entirely in series or entirely in parallel. Mixed arrangements and unequal values require a separate calculation.

Parallel: total = individual × quantity. Series: total = individual ÷ quantity. The main voltage is the voltage across the entire bank; this helper does not evaluate voltage sharing or capacitor ratings.

Lung protection boundary exclusion: Electric double-layer capacitors (EDLCs) are excluded from this calculator’s lung protection boundary assessment. This exclusion does not apply to all supercapacitor technologies and does not establish freedom from other hazards.

Calculation method and review notes

Grounding threshold interpretation: The NFPA 70E (2027) ranges reviewed by ElecTrain leave exactly 1,000 J and 100 kJ unassigned. This calculator includes those endpoints in the higher grounding category: soft then hard grounding at ≥1,000 J and below 100 kJ; engineered and redundant remote testing and grounding at ≥100 kJ. These inclusive comparisons are ElecTrain’s implementation choice.

Stored energy = ½CV² using peak capacitor voltage. Open-air incident energy = joules ÷ (52.6 × distance in centimeters²). The enclosure estimate is three times the open-air estimate. Arc flash boundaries follow the workbook: 0.05√joules inches in open air, multiplied by √3 for an enclosure.

Hearing boundary estimates follow the supplied empirical equation. Lung protection above 122 kJ requires further assessment. Negative calculated protection boundaries are shown as N/A (not applicable within the equation range).

Estimates reproduce the supplied ElecTrain workbook. They do not establish task-specific PPE, safe approach distances, or a safe discharge procedure. Confirm model applicability, equipment configuration and work practices through a qualified assessment.

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