Circuit Protection & Grounding

Arc Flash Incident Energy Calculator – IEEE 1584-2018

Calculate IEEE 1584-2018 arcing current, incident energy, and arc-flash boundary for normal and reduced-current clearing-time scenarios.

IEEE 1584-2018 arc-flash calculation

The empirical model calculates arcing current at voltage anchor points, applies geometry and enclosure corrections, then repeats the energy calculation for reduced arcing current.

Iarc,min = Iarc × (1 − 0.5 × VarCf)
E = IEEE1584(Voc, Ibf, Iarc, G, D, EC, CF, t)
AFB: E(AFB) = 1.2 cal/cm²

where:

Iarc
Predicted normal arcing current[kA]
Iarc,min
Reduced arcing current used for the second clearing-time scenario[kA]
Ibf
Bolted three-phase fault current[kA]
G
Conductor gap[mm]
D
Working distance[mm]
EC
Electrode configuration
CF
Enclosure size correction factor
AFB
Arc-flash boundary[mm]

IEEE 1584 predicts thermal incident energy and boundary; it does not select PPE or authorize energized work.

How to use the Arc Flash Incident Energy Calculator – IEEE 1584-2018

Calculate IEEE 1584-2018 arcing current, incident energy, and arc-flash boundary for normal and reduced-current clearing-time scenarios. Start by choosing the operating mode, then enter values from nameplates, measurements, or project documents in the units shown. The result updates immediately and keeps intermediate quantities visible for review.

  1. Confirm the system and calculation mode.
  2. Enter measured or manufacturer-rated values.
  3. Review the primary result and intermediate metrics.
  4. Continue with the related protection or equipment-selection checks.

Calculation method and validation

The equations and symbol definitions above show the complete calculation basis. Inputs are checked before calculation so zero, negative, incompatible, or physically impossible combinations are flagged instead of silently producing a misleading result.

How to interpret the result

Use the main result as a starting value and read every supporting metric. Three-phase 50/60 Hz AC system within the IEEE 1584-2018 model range Bolted fault current comes from a current short-circuit study Each clearing time includes relay sensing, intentional delay, breaker mechanism, and interruption time at the calculated arcing current A passing or recommended result means the entered mathematical conditions are satisfied; it does not certify the complete installation or a particular product combination.

  • Three-phase 50/60 Hz AC system within the IEEE 1584-2018 model range
  • Bolted fault current comes from a current short-circuit study
  • Each clearing time includes relay sensing, intentional delay, breaker mechanism, and interruption time at the calculated arcing current

Selection limits and next checks

This calculator does not replace a site-specific arc-flash study, protective-device coordination study, equipment inspection, or qualified electrical safety assessment. IEEE 1584 does not recommend PPE or determine whether energized work is justified. Do not convert the result automatically into a PPE category. Use the exact protective-device curve at both displayed arcing currents; a reduced current can produce a longer clearing time and higher incident energy. Compare the output with the current applicable standard, local rules, exact VIOX product datasheet, environmental conditions, protection coordination, and the engineer's project requirements before procurement or installation.

Assumptions

  • Three-phase 50/60 Hz AC system within the IEEE 1584-2018 model range
  • Bolted fault current comes from a current short-circuit study
  • Each clearing time includes relay sensing, intentional delay, breaker mechanism, and interruption time at the calculated arcing current

Important Warnings

  • This calculator does not replace a site-specific arc-flash study, protective-device coordination study, equipment inspection, or qualified electrical safety assessment.
  • IEEE 1584 does not recommend PPE or determine whether energized work is justified. Do not convert the result automatically into a PPE category.
  • Use the exact protective-device curve at both displayed arcing currents; a reduced current can produce a longer clearing time and higher incident energy.

FAQ

Why are two clearing times required?

IEEE 1584-2018 evaluates normal and reduced arcing current. The reduced current can move a breaker or fuse into a slower part of its time-current curve, producing the worst incident energy.

Does a result below 1.2 cal/cm² mean the work is safe?

No. It only describes predicted thermal incident energy at the entered distance. Shock, arc likelihood, equipment condition, task risk, maintenance, and work-practice requirements remain separate.

Can this calculate single-phase or DC arc flash?

No. IEEE 1584-2018 covers three-phase AC equipment from 208 V to 15 kV. Single-phase and DC systems require other methods.