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Arcing Current Variation Correction Factor Equation and Calculator per IEEE 1584-2018

Electrical and Electronics Design and Engineering

Arcing Current Variation Correction Factor Equation and Calculator per IEEE 1584-2018

This calculator and equation will determine the arcing current at the open circuit voltage. Requires premium membership account to access calculator.

Related:

Arc Flash Hazard Calculations Procedure and Considerations For Medium Voltage System 

NOTE:

• Values calculated on the is page are applicable only when V_oc ( open-circuit voltage) is between 600 V and 15,000 V. I_{arc_600}, I_{arc_2700}, and I_{arc_14300} (intermediate average arcing currents). The final Iarc value inherits the correction factor.
• When 208 V ≤ Voc ≤ 600 V: To Iarc (final current only). See: Interpolation Arcing Current Equations and Calculator

Preview: Arcing Current Variation Correction Factor Equation and Calculator per IEEE 1584-2018

Where:

VarC_f is the arcing current variation correction factor
I_arc is the final or intermediate rms arcing current(s) (kA) (see note)
I_{arc_min} is a second rms arcing current reduced based on the variation correction factor (kA)
V_oc is the open-circuit voltage between 208 kV and 15.0 kV
k1 to k10 = coefficients provided in Table B given below

VCB: Vertical conductors/electrodes inside a metal box/enclosure
VCBB: Vertical conductors/electrodes terminated in an insulating barrier inside a metal box/enclosure
HCB: Horizontal conductors/electrodes inside a metal box/enclosure
VOA: Vertical conductors/electrodes in open air
HOA: Horizontal conductors/electrodes in open air

Table B - Coefficients for Equation

E.C.	k1	k2	k3	k4	k5	k6	k7
VCB	0	−0.0000014269	0.000083137	−0.0019382	0.022366	−0.12645	0.30226
VCBB	1.138e-06	−6.0287e-05	0.0012758	−0.013778	0.080217	−0.24066	0.33524
HCB	0	−3.097e-06	0.00016405	−0.0033609	0.033308	−0.16182	0.34627
VOA	9.5606E-07	−5.1543E-05	0.0011161	−0.01242	0.075125	−0.23584	0.33696
HOA	0	−3.1555e-06	0.0001682	−0.0034607	0.034124	−0.1599	0.34629

NOTE:

The correction factor (1 – (0.5 × VarCf )) is applied as follows:

• 208 V ≤ Voc ≤ 600 V: To Iarc (final current only)
• 600 V < Voc ≤ 15 000 V: To Iarc @ 600, Iarc @ 2700, and Iarc @ 14300 (intermediate average arcing currents). The final Iarc value inherits the correction factor.
  The “0.5” coefficient indicates that variation is applied to the average arcing current to obtain a lower-bound value arcing current.

Reference:

IEEE 1584-2018

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