You are here: Home > Support > Knowledge Base > Arc-Flash Settings and Sensitivity (IEEE Std 1584-2018)

Arc-Flash Settings and Sensitivity (IEEE Std 1584-2018)

Thursday, May 23rd, 2019

When calculating arc-flash for a piece of distribution equipment, there are numerous settings you can adjust to change the resulting arcing current and incident energy values:

  • The electrode configuration as described in IEEE Std 1584-2018 Table 9
  • The dimensions of the enclosure
  • The size of the gap between conductors
  • The working distance
  • The arcing time

The size of the change in the arcing current and incident energy differs for each setting. The charts below illustrate the sensitivity of each setting.

Arcing current is not shown for settings that do not affect it.

The data is based upon a 480V panel with a bolted fault current of 100,000 A and the default known settings.

Electrode Configuration

The electrode configuration has some impact on the arcing current and incident energy. If the enclosure type is the same, a vertical configuration will have lower values than a horizontal configuration. Also, enclosed electrodes will have higher values than electrodes in the open air.

Enclosure Dimensions

The chart below shows the results for square enclosures from 5″x5″ to 50″x50″ with depths greater than 8″ and depths less than/equal to 8″. In most cases, the dimensions of the enclosure do not significantly impact the incident energy. As the enclosure size increases past 20″ square, the incident energy steadily decreases. The incident energy does not change if the size decreases under 20″ square unless the depth also decreases to 8″ or less; a shallow enclosure less than 20″ square will have roughly half the incident energy of a deeper enclosure.

Gap Between Conductors

Incident energy will increase and arcing current will decrease as the gap increases, but the difference is not significant.

Working Distance

Working distance is the second most significant factor when calculating arc-flash. As the working distance increases, incident energy decreases exponentially.

Arcing Time

Arcing time is by far the most significant factor when calculating arc-flash. There is an almost thirty-fold increase in incident energy from 0.0167 seconds (one cycle) to 0.5 seconds. If the arc lasts for 2 seconds, the incident energy is 120 times what it is at one cycle.

Related Articles

Filter by
Post Page
Electrical Electrical RT Calculations Electrical RT General HVAC Plumbing Distribution Equipment (Panels and Transformers)
Sort by

Arc-Flash Settings and Sensitivity (IEEE Std 1584-2002)

There are several factors that can influence arc-flash calculations, such as the working distance and whether the distribution equipment is enclosed.

18

Electrode Configurations for Arc-Flash Calculations

This article will help you determine the electrode configuration for your distribution equipment, in order to perform arc-flash calculations.

8

Reading and Configuring Time-Current Curves

A brief explanation of what each part of the time-current curve represents and how you can make changes to the curve in Design Master Electrical.

8

“Required PPE” Removed From Arc-Flash Schedule

In Design Master Electrical 8.6 and Electrical RT 1.4, “Required PPE” was removed from arc-flash schedules to follow the latest guidance from NFPA 70E.

0

Exporting to IFC and Alignment Points

If your exported IFC file does not line up properly, you may need to adjust your alignment point.

0

Panel Schedule Blocks Are Mismatched

If your panel schedule headers and/or footers are coming in misaligned, you need to update the schedule blocks on the drawing and possibly in your customization.

0

Products

Electrical for Revit

Electrical for AutoCAD

HVAC for AutoCAD

Photometrics for AutoCAD

System Requirements

Support

Contact Support

Install & Update Instructions

Online Training

Knowledge Base

User Manuals

Tutorials

Release Notes

Downloads

Wish List

Remote Support

Company

About

Customer Stories

Awards

Newsletter

Blog

Pricing

Electrical for Revit

Electrical for AutoCAD

HVAC for AutoCAD

Photometrics for AutoCAD

Free Trial

Electrical for Revit

Electrical for AutoCAD

HVAC for AutoCAD

Photometrics for AutoCAD

©2001-2020, Design Master Software, Inc