Understand the severity of arc flash injuries based on proximity, explosion size, and exposure time. This comprehensive program combines two critical areas:Arc Flash & Low Voltage Safety and Electrical Switching Safety for Operators.Įxplore arc flash hazards, boundaries, and appropriate PPE. Print labels,The following labels can be printed on plastic stock through most laser printers, or via commercially available label printers.Welcome to our 2-day Electrical Safety and Arc Flash Awareness Course, meticulously crafted for operators seeking to enhance their expertise in electrical safety. Going much lower than this may result in current values that cannot be realistically maintained.ĥ) Compare the incident energies of the case selected in task 4 above with the high impedance values with of the same case.

Note: A good starting place is 80% of the calculated arcing current. This will lower the arcing current, which may cause longer trip times and result in higher incident energies. Take the case with the highest values (there may be multiple cases for different parts of the system) and modify the arcing current to reflect a high impedance arcing current. SummaryĢ) Switch to different operating modes as defined in Scenario Manager.ģ) Run arc-flash calculations for each operating mode to determine highest arc hazard.Ĥ) Compare the highest incident energies from the base case and scenarios. This scenario is common to plants where an accurate protective device coordination study has never been performed, or where workers unfamiliar with protection system requirements make changes to protective device settings. This increases the PPE requirement from 3 to 4, significantly increasing costs, and the probability workers may try and bypass the higher PPE clothing requirements.

In Figure-8, the substation secondary main breaker provides selective coordination using either setting, however, the arc-flash incident energy is increased from 11 cal/cm to 29 cal/cm for the higher short time delay setting. Obviously, the head, and chest areas are more critical to survival that fingers or arms. The degree of injury depends on the percentage of the person’s skin that is burned, and the critical nature of the burn. Working Distance: The arc flash boundary and associated protection requirements are based on the incident energy levels available to the persons chest or face, not the hands or arms. These include, working distances, units of measurement, threshold boundaries, and the calculation standard or the “equations” for the analysis. Step-3 Working Distance and Threshold Boundariesīefore running the actual analysis portion of the study, the user should determine the parameters on which the study will be based.

In summary, Arc Flash assessment should include each operating mode for the power system to insure correct incident energies are calculated for all system conditions. The examples above consider a double ended utility tie system, but the application applies to low voltage systems with tie breakers or where emergency generation provides stand alone power or works in parallel with the normal system. Both utility sources are on line and the switchgear tiebreaker is open, reducing the available short circuit current on each bus. In Figure-3, an example system with minimum short circuit current is shown. These changes can have a significant impact on the arc-flash hazard and the PPE requirements for each piece of equipment. What is important to realize is that each one of these conditions may change the level of short circuit current, which in turn changes the clearing time of the protective devices. Large motors or process sections not in operation.Tie breakers which can be operated open or closed.Parallels feeds to Switchgear or MCC’s.Maintenance conditions where short circuit currents are low and trip time high.This may be with only small backup generators. Multiple generator sources that are operated in parallel or isolated depending on the system configuration.Multiple utility sources that are switched in or out.However, for larger plants, there may be multiple modes of operation. For plants with simple radial service from the utility, only one mode of operation typically exists – normal.

Est Arc Flash boundaries