Calculation example based upon the IEEE 1584 circuit breaker equations

Consider 575V motor control centre and 20 kA prospective 3-phase bolted fault current at its terminals. The gear is being protected by molded case 200A rated circuit breaker (MCCB). Incident Energy at working distance of 500mm, Flash Protection Boundary and Personal Protective Equipment (PPE) Category will be calculated based on IEEE 1584 Guide for Performing Arc-Flash hazard Calculations formulae for calculating arc flash energies (Low Voltage Circuit Breaker Equations).

We start with specifying Working Distance, Available 3-Phase Bolted Current, System Voltage, breaker instantanenous trip current and selecting Breaker Type. For cases where voltage is beyond 208 to 480 and 575 to 690V ranges, or available fault current and gap is outside the range of the model, the IEEE 1584 Empirically Derived Model can be applied and it is included in the Arc Flash Analytic v4.1 calculator.

Figure 1 - Circuit Breaker Equations Front Screen

System Summary and Calculation Results screen will be displayed by hitting [Next] button.

Figure 2 - Circuit Breaker Equations Results Screen

By pressing [Save Results] button, the results will 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 ( see Figure 1 above) you can open an existing results file, inspect its current content, do simple editing operations including Cut, Copy and Paste to and from the clipboard, Save and Print. If you need more complex editing, import the file into your favorite text manipulation processor ( MS Word as an example ) and do what you need to do.

Warning Label can be generated by clicking on [Create Label] button. The label can be saved on local drive and printed on system printer. The program allows saving of the generated warning labels in JPG, BMP and PDF electronic formats for ease of scaling and for printing multiple labels on standard label stock directly, or from Word, Page Maker or other word processor. You will be able to assign a unique equipment name for each label before you save it on the hard drive.

Figure 3 - Label Preview

You can click on Label from Options menu ( see Figure 1 above) to select the equipment, arc flash hazards and creation date information displayed on warning label. You can also select label type (Color or Black and White), label language ( English, French or Spanish ) and add in few more lines of text information onto the label.

Figure 4 - Label Options