Arc flash calculations & label making software and mobile apps

By clicking on Settings -> Units Of Measurement menu item, metric (mm, Joules, kg, N/m^2) and imperial units (inches, calories, lb, lb/ft^2 ) can be selected for gap between conductors, working distance, arc flash boundary, limited and restricted boundaries, incident energy, initial pressure developed by an arc and arc flash TNT mass equivalent.

By clicking on Settings -> Incident Energy at AFB menu item, Preset or Evaluated incident energy at arc flash boundary can be selected. With Preset option selected, enter a value in cal/cm² or Joules/cm² to determine arc flash boundary (AFB) distance at that incident energy. The incident energy of 1.2 cal/cm² (5 J/cm²) for bare skin is used in solving equation for arc flash boundary in IEEE 1584 Guide for Performing Arc Flash Hazard Calculations. However, the Guide equation for arc flash boundary can be solved with other incident energy levels as well such as the rating of proposed personal protective equipment (PPE). Values withing the 0.3 cal/cm² to 4 cal/cm² range are accepted in this program version.

For exposures lasting less than 1 second the irradiance required for second degree burn at bare skin exposure would significantly increase as the duration of exposure decreased however it was shown that the amount of incident energy required to cause the burn would decrease. With Evaluated option selected, the program will determine the amount of incident energy to second degree based on heat flux intensity and use that incident energy value to calculate arc flash boundary.

By clicking on Settings -> Arc Duration Cut-Off menu item, designated upper limit of arc duration for incident energy and arc flash boundary calculations can be selected in 2 to 10 seconds range.

It's usually assumed that the outer limit for the arcing time is no more than 2 seconds. Although this is not a hard and fast rule, it accounts for the likelihood that the arcing material in an arcing field will likely be either burned off or expelled by the force of the blast. In any case, this would extinguish the arc event. Also, IEEE 1584 states "If the time is longer than two seconds, consider how long a person is likely to remain in the location of the arc flash. It is likely that a person exposed to an arc flash will move away quickly if it is physically possible and two seconds is a reasonable maximum time for calculations".

When arc duration exceeds selected arc duration cut-off, the program will report both actual arc duration and incident energy at ADC values.

By clicking on Settings -> Site Specific PPE Recommendations menu item, personal protective equipment (PPE) recommendations displayed on labels created using the program can be reviewed, edited or reset to default values. The feature will let you making necessarily PPE adjustments required for various tasks in English and a variety of international languages. Also, the PPE requirements in new NFPA 70E standard have changed from previous editions of the standard. They may change again and the feature will let you reflect the changes as the safety standard evolves.

The program allows to save equipment configuration for future reference. Specify Equipment Name and select File -> Save Current Equipment to Database menu option to save the equipment configuration to database.

Select File -> Browse Saved Records menu option to open up the database containing saved equipment configurations.

Select a record and click on [Import Record] button to copy the data into the program main window.

The program will populate input data fields with the selected equipment configuration.

By pressing [Save Results] button on System Summary and Calculation Results screen, the results can be saved to a text file for future reference or printing. You can save results for different jobs under different names.

By choosing Open from File menu you can now open an existing results file, inspect its current content, do simple editing operations including Copy to clipboard and Save.

If you need more complex editing, import the file into your favorite text manipulation processor (MS Word as an example) and do what need to be done.

The program allows to create and save generated warning labels in electronic JPG, GIF, TIF, BMP (BitMap) and PDF formats.

Click on [Create Label] from System Summary and Calculation Results screen.

The Label Preview window will open up. Select label size, type, layout and language and click on [Save] button to save the label on your drive.

The program allows to send arc flash labels directly to print. Click on [Create Label] from System Summary and Calculation Results screen. The Label Preview window will open up. Select label size, type, layout and language and click on [Print Label ...] button or select Printing menu Print Label ... item to send the label to print.

You will be able to select printer and fine tune printing preferences including paper size, layout, quality etc. prior to printing the label.

You can also click Printing menu Print Preview item to make sure you have selected proper print settings, and click printer icon to print the label.

If you do label printing on a regular base, consider assigning default label printer and applying select printing preferences in your system Print Manager. You can access the Print Manager from Control Panel on your PC system.

Click on Library menu item and then select Fuses or Circuit Breakers to open up circuit protection device maintenance dialogue:

Figure 1. Fuse Maintenance Dialogue

Figure 2. Circuit Breaker Maintenance Dialogue

You can click on column headings in maintenance dialogue to sort the data by make, series, part number, current, voltage, I.R. ratings etc.

You can add device if it is not already included in build-in fuse or circuit breaker library. Click [Add Fuse ...] or [Add Breaker ...] button respectively and fill out the new device information form.

Figure 3. New Circuit Breaker Dialogue

Figure 4 below shows representative circuit breaker tripping curve.

Figure 4. Sample Circuit Breaker Time-Current Characteristics

Follow vertical orange line until it intersects the horizontal axis. The point of intersection corresponds to Max Instantaneous Pickup on Figure 3 above.

Follow horizontal orange line until it intersects the vertical axis. The point of intersection corresponds to Instantaneous Trip Time on Figure 3 above.

Follow vertical blue line until it intersects the horizontal axis. The point of intersection corresponds to Short Time Pickup on Figure 3 above.

Follow horizontal blue line until it intersects the vertical axis. The point of intersection corresponds to Short Time Delay on Figure 3 above.

Find a point on breaker trip curve where maximum instantaneous trip line (upright orange line on Figure 4 below) breaks and starts departs from vertical. Follow from the point to the left until intersection with the time axis. The point of intersection corresponds to Minimum Thermal Trip Time on Figure 3 above.

Find ten (10) seconds point on time axis (vertical). Follow from it to the right until it intersects the breaker curve. Then follow that line straight down to the horizontal axis (current, Current Rating). The value corresponds to Tripping Current at 10 sec on Figure 3 above.

Click [Save] button below to add a new device into the database. The new device will now appear in protection device maintenance list.

To add a fuse, the program requires a set of five points from the fuse average melting time-current characteristics in 0.01 to 10 seconds interval. You need published fuse time-current characteristic or consult the fuse manufacturer to obtain the information.

Figure 5. Fuse Information Dialogue

As an example, lets find out what current will open the fuse in 0.1 second. On the vertical axis (time in seconds) find 0.1 second and follow that line to the right until it intersects the fuse curve. Then follow that line straight down to the horizontal axis (current in Amperes) and read the current value. Repeat the steps above for remaining points.

Figure 6. Sample Fuse Time-Current Characteristics