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IEEE 1584-2018 Arc Flash Procedure Equations and Calculations

Electrical and Electronics Design and Engineering

IEEE 1584-2018 Arc Flash Equations and Calculations

Arc Flash Hazard Calculations Procedure and Considerations For Medium Voltage System

Arc flash is defined as the sudden release of energy due to uncontrolled electric arc which is the product of short circuit current and arc duration. Typically there is a plasma cloud created when metals vaporize and gas temperatures can reach 35,000°F.

Note that this webpage is an overview and only qualified professionals should approve design and analysis of Arc Flash Equations and Calculations per. IEEE 1584-2018.

Arc Flash Causes:

• Human error (the #1 cause)
  • Accidental contact by person or tool (engineers are not exempt)
  • Incorrect assembly/repair
  • Incorrect tool use
• Mechanical failure
  • Lack of maintenance
  • Material defect
• Foreign object intrusion
  • Dust/debris
  • Water
  • Animals
• Faults or Current overload
  • Stressed/weakened components

Standards of consideration

• OSHA 29 CFR 1910 (revised 2014)
  • Effective April 1, 2015
• NEC - NFPA 70-2017 (revised every 3 years)
• NFPA 70E-2018 (revised every 3 years)
• IEEE 1584-2018 superceding IEEE 1584-2002

IEEE 1584-2018

Please note there there are several possible paths in an analysis of Arc-Flash Incident Energy of a voltage system. Consult IEEE-1584-2018 for details and procedures.

The following is the general procedure/steps for an incident energy and arc-flash boundary calculation for a medium-voltage system:

Step 1)

Define system and input parameters:

• Voltage (Voc) kV
• I_bf = Bolted fault current for three phase faults (symmetrical rms) (kA)
• Conductor Gap (G) mm
• Working Distance (D) mm
• Configuration of bus or electrode
  • VCB (Vertical Electrodes in a Closed Box)
  • VCBB (Vertical Electrodes terminated in an insulating barrier, Metal "Box" Enclosure)
  • HCB (Horizontal Electrodes in a Closed Box)
  • VOA (Vertical Electrodes in Open Air)
  • HOA (horizontal Electrodes in Open Air)
• Enclosure Dimensions
  • IEEE 1584-2018 Electrical Bus Gaps Typical by Enclosure Size 
  • Height of Enclosure mm
  • Width of Enclosure mm
  • Depth of Enclosure mm
• Arc duration time current characteristic (TCC) curve of component(s) (Final arc time (T) derived from "Interpolation Arcing Current Equations and Calculator".

Step 1:

Calculate: Intermediate Arcing Current I_{arc_600}, I_{arc_2400}, or I_{arc_14300} (kA)

Step 2:

Calculate Final Arcing Current I_arc (kA) and determine arc duration T ( ms ) from fuse, etc. data.

Step 3:

Enclosure Size Equivalent Height and Width Correction Factor CF, ESS

Step 4:

Intermediate Value of Incident Energy E_{arc_600}, E_{arc_2400}, or E_{arc_14300} (J / cm²)

Step 5:

Final Value of Incident Energy E E₆₀₀, E₂₇₀₀, E₁₄₃₀₀ and E_≤600 (J / cm²)

Step 6:

Intermediate Value of Arc-Flash Boundary AFB₆₀₀, AFB₂₄₀₀, or AFB₁₄₃₀₀(mm)

Step 7:

Final Arc-Flash Boundary AFB₁, AFB₂ AFB₃, and AFB (mm)

Step 8: (To account for the arcing current variations)

Arcing Current Variation Correct Factor ( 1 - 0.5 VarC_f )

Step 9:

Final Values of Arcing Current using the Correction Factor I_arc (kA) and T (ms)

Step 10:

Repeat Step 4 using Reduced Arcing Current E_{arc_600}, E_{arc_2400}, or E_{arc_14300} (J / cm²)

Intermediate Value of Incident Energy

Step 11

Repeat Step 4, Reduced Intermediate Currents

Intermediate Value of Incident Energy E_{arc_600}, E_{arc_2400}, or E_{arc_14300} (J / cm²)

Step 12

Repeat Step 5 using the reduced arcing currents.

Final Value of Incident Energy E E₆₀₀, E₂₇₀₀, E₁₄₃₀₀ and E_≤600 (J / cm²)

Step 13

Repeat Step 6 using the reduced arcing currents.

Intermediate Value of Arc-Flash Boundary AFB₆₀₀, AFB₂₄₀₀, or AFB₁₄₃₀₀(mm)

IEEE 1584-2018

Verify results and send feedback if a discrepancy is found.