# Online Arc Flash Calculator IEEE 1584 (2002 and 2018)

Calculate Arc Flash Boundary and Arc Flash Incident Energy with the Free Arc Flash Calculator. Supports IEEE 1584-2002, IEEE 1584-2018, and the Ralph Lee Method.

 Standard IEEE 1584-2002IEEE 1584-2018Ralph Lee Method Unit of measure ImperialMetric Voltage Vac Fault current kA Arcing time for Iarc ms Arcing time for Iarc_min ms Equipment type SwitchgearMCCs and Panels, ShallowMCCs and Panels, DeepCable Junction Box, ShallowCable Junction Box, Deep
 Working distance in Enclosure width in Enclosure height in Enclosure depth in Electrode configuration Vertical in Box -VCBVertical in Box with Barrier -VCBBHorizontal in Box -HCBVertical in Open Air -VOAHorizontal Open Air -HOA Conductor gap mm

## Parameters for the IEEE 1584 2018 Arc Flash Calculator

• Standard: Select IEEE 1584-2018 or IEEE 1584-2002.
• Unit of measure: Imperial (in) or Metric (mm). Note that Conductor Gap is always in metric.
• Voltage (Vac): Enter an AC voltage between 208 V and 15,000 V. AC voltage levels outside of this range, and DC voltage levels, are not supported by the IEEE 1584-2018.
• Fault current (kA): Three-phase bolted prospective fault current in kA.
• Arcing time for Iarc (ms):
• The fault clearing time for the calculated normal arching current.
• Include the protection relay and circuit breaker clearing time.
• Follow a three-step process to specify the arching time:.
• Step 1: Leave the default time value, and click on Calculate.
• Step 2: Use the calculated arcing current Iarc to determine the actual fault clearing time for your protection system,
• Step 3: Click on Calculate again, to calculate the Incident Energy and Arc Flash Boundary.
• Note that the time does not affect the magnitude of the acing current.
• Arcing time for Iarc_min (ms):
• The purpose of this is to calculate the Incident Energy and Arc Flash Boundary for a scenario where the fault clearing time may be longer due to a reduced arcing current.
• This is the arcing time for the calculated reduced arcing current.
• Follow the same steps as explained above for the arcing time for the normal arcing current.
• Working distance (inch or mm): The working distance from the arc location. This field is pre-populated with typical distances from IEEE 1584 2018, which is based on the Equipment Type.
• Equipment Type:
• The Equipment Type is used to pre-populate the following distances and sizes with typical values from the IEEE 1584 2018:
• Working Distance.
• Enclosure Sizes (width, height, and depth).
• Conductor Gap.
• You can change these values after you have selected the equipment type.
• The Equipment Type is not used in the calculations. Only the values are used.
• Enclosure width, height and depth (inch or mm): You can change the typical enclosure (box) sizes here. These values are pre-populated with typical values from IEEE 1548 2018, based on the selected Equipment Type.
• Electrode configuration: Choose from the following:
• VCB: Vertical conductor (electrode) in a box.
• VCBB: Vertical conductor (electrode) in a box terminated in an insulating barrier.
• HCB: Horizontal conductor (electrode) in a box.
• VOA: Vertical conductor (electrode) in open air.
• HOA: Horizontal conductor (electrode) in open air.
• Conductor gap (mm): The distance between the conductors (electrodes). This value is always in mm. It is pre-populated with typical values from IEEE 1548 2018, based on the selected Equipment Type.

## Parameters for the IEEE 1584 2002 Arc Flash Calculator

• Standard: Select IEEE 1584-2018 or IEEE 1584-2002.
• Unit of measure: Imperial (in) or Metric (mm). Note that Conductor Gap is always in metric.
• Voltage (Vac): Enter an AC voltage between 208 V and 15,000 V. AC voltage levels outside of this range, and DC voltage levels, are not supported by the IEEE 1584-2002.
• Fault current (kA): Three-phase bolted prospective fault current in kA.
• Arcing time for Iarc (ms):
• The fault clearing time for the calculated normal arching current.
• Include the protection relay and circuit breaker clearing time.
• Follow a three-step process to specify the arching time:.
• Step 1: Leave the default time value, and click on Calculate.
• Step 2: Use the calculated arcing current Iarc to determine the actual fault clearing time for your protection system,
• Step 3: Click on Calculate again, to calculate the Incident Energy and Arc Flash Boundary.
• Note that the time does not affect the magnitude of the acing current.
• Working distance (inch or mm): The working distance from the arc location. This field is pre-populated with typical distances from IEEE 1584 2018, which is based on the Equipment Type.
• Equipment Type:
• The Equipment Type is used to pre-populate the following distances and sizes with typical values from the IEEE 1584 2002:
• Working Distance.
• Conductor Gap.
• You can change these values after you have selected the equipment type.
• The Equipment Type is used in the calculations.
• Grounding: The grounding type is used in calculations.
• Conductor gap (mm): The distance between the conductors (electrodes). This value is always in mm. It is pre-populated with typical values from IEEE 1548 2018, based on the selected Equipment Type.

## Ralph Lee Method

The calculator also supports the Ralph Lee Method, which is one of the proposed methods in the NFPA 70E standard.

## PPE Categories in NFPA 70E 2018

There are two official Arc Flash Analysis (Study) methods defined by NFPA 70E:

• Incident Energy Analysis Method
• Arc Flash PPE Category Method
You can read more about it in What is an Arc Flash Study? Two Official Methods Described

This calculator is based on the Incident Energy Method.

According to NFPA 70E, PPE Categories should not be used when the Incident Energy Method is used. However, NFPA 70E allows site-specific PPE requirements on Arc Flash Labels, and in many cases, sites adopt the PEE Categories anyway.

For more information see 5 Minimum Arc Flash Label Requirements from NFPA 70E 2018

Therefore, I have included the mapping to Arc Flash Categories in the calculator.

The PPE in NFPA 70E is defined into 4 categories.

Table 1: NFPA 70E PPE Categories
Category Minimum arc rating of PPE
0 1.2 cal/cm2
1 4 cal/cm2
2 8 cal/cm2
3 25 cal/cm2
4 40 cal/cm2

Note that Category 0 is not listed in NFPA 70E. I have included it here when the incident energy is less than 1.2 cal/cm2. In other words, when the Arc Flash Boundary is less than the working distance.

## Equipment types with typical distances and sizes for IEEE 1584 2018

Abbreviations used in Table 2 and Table 3:

 Gap Conductor Gap (mm) WD Working distance (inch or mm) H Enclosure height (inch or mm) W Enclosure width (inch or mm) D Enclosure depth (inch or mm)

Table 2: Equipment Types with Typical Imperial Distances and Measurements (IEEE 1584 2018)
Equipment type Gap mm WD in H in W in D in
15 kV Switchgear 152 36 45 30 30
15 kV MCC 152 36 36 36 36
5 kV Switchgear, Large 104 36 36 36 36
5 kV Switchgear, Small 104 36 45 30 30
5 kV MCC 104 36 26 26 26
LV Switchgear 32 24 20 20 20
LV MCCs and Panels, Shallow 25 18 14 12 8
LV MCCs and Panels, Deep 25 18 14 12 9
Cable Junction Box, Shallow 13 18 14 12 8
Cable Junction Box, Deep 13 18 14 12 9

Table 3: Equipment Types with Typical Metric Distances and Measurments (IEEE 1584 2018)
Equipment type Gap mm WD mm H mm W mm D mm
15 kV Switchgear 152 914 1143 762 762
15 kV MCC 152 914 914 914 914
5 kV Switchgear, Large 104 914 914 914 914
5 kV Switchgear, Small 104 914 1143 762 762
5 kV MCC 104 914 660 660 660
LV Switchgear 32 610 508 508 508
LV MCCs and Panels, Shallow 25 457 355.6 305 203
LV MCCs and Panels, Deep 25 457 355.6 305 229
Cable Junction Box, Shallow 13 457 355.6 305 203
Cable Junction Box, Deep 13 457 355.6 305 229

## Equipment types with typical distances and sizes for IEEE 1584 2002

Table 4: Typical Conductor Gaps in IEEE 1584 2002
System voltage Equipment type Conductor gap
0.208-1 kV Open air 10-40 mm
Switchgear 32 mm
MCCS and panels 25 mm
Cables 13 mm
>1-5 kV Open air 102 mm
Switchgear 13-102 mm
Cables 13 mm
>5-15 kV Open air 13-153 mm
Switchgear 153 mm
Cables 13 mm

Table 5: Typical working distances in IEEE 1584 2002
System Working distance
15-kV switchgear 910 mm
5-kV switchgear 910 mm
Low-voltage switchgear 610 mm
Low-voltage MCCs and panelboards 455 mm
Cable 455 mm

## How to calculate the Arc Flash Boundary with IEEE 1584 2018?

The Arc Flash Boundary is calculated according to IEEE 1584 2018 as follows:

1. Calculate the intermediate arching currents Iarc_600, Iarc_2700 and Iarc_14300 at 600 V, 2700 V and 14300 V.
2. Calculate the final arcing current Iarc at the specified open circuit operating voltage Voc.
3. Calculate the enclosure size correction factor CF for the relevant electrode configuration and enclosure size.
4. Calculate the intermediate arc flash boundaries AFB600, AFB2700 and AFB14300 at 600 V, 2700 V and 14300 V.
5. Calculate the final arc flash boundary AFB at the specified open circuit operating voltage Voc.

## How to calculate the Arc Flash Incident Energy with IEEE 1584 2018?

The Arc Flash Incident Energy is calculated according to IEEE 1584 2018 as follows:

1. Calculate the intermediate arching currents Iarc_600, Iarc_2700 and Iarc_14300 at 600 V, 2700 V and 14300 V.
2. Calculate the final arcing current Iarc at the specified open circuit operating voltage Voc.
3. Calculate the enclosure size correction factor CF for the relevant electrode configuration and enclosure size.
4. Calculate the intermediate arc flash boundaries E600, E2700 and E14300 at 600 V, 2700 V and 14300 V.
5. Calculate the final Incident Energy E at the specified open circuit operating voltage Voc.