The guide says “sustainable arcs are possible, but less likely, in three-phase systems operating at 240 V AC nominal or less with an available short-circuit current less than 2,000 A.” For 208-V AC three-phase electrical equipment at 2,000 A, the available fault current is typically a 45-kVA or higher transformer size and all related panelboards will require calculations. Step 3: Address three-phase electrical equipment. For motor contributions less than or equal to 50 hp-and in some cases with client requirements for motors less than 200 hp-lump the motors. You need to consider single mode or multiple modes when determining both low (minimum) and high (maximum) bolted fault currents. This is different from strictly completing a short circuit analysis. Step 2: Determine the system modes of operation. Configure the ‘software arc flash module’ before starting calculations. With this data, create a digital single line diagram model in power engineering software. Start with an available single line diagram, use specific electrical equipment data sheets and request electrical utility fault data for each service. Step 1: Collect the system and installation data. When calculating arc flash hazard incident energy, IEEE 1584-2018 requires the following steps to be completed. ![]() With both documents, an electrical engineer can substantiate any assumptions/parameter selections and/or disclaimers they may include in reports to their clients. IEEE 1584.1 was first published in 2013-as a companion to IEEE 1584, Guide for Performing Arc-Flash Hazard Calculations-to ensure such incident energy analysis studies were completed correctly, with a detailed report aligned with good engineering practices. This is unfortunate, as the guide explains steps to complete a power system study, calculate arc flash incident energy and boundary and generate a quality engineering report. ARCAD Arc Flash Analytic software automatically selects either IEEE empirical model or Lee method for arc flash calculations based on input system parameters.Not many electrical engineers across Canada seem to be aware of Institute of Electrical and Electronics Engineers (IEEE) 1584.1, Guide for the Specification of Scope and Deliverable Requirements for An Arc-Flash Hazard Calculation Study in Accordance with IEEE Std 1584. For cases where voltage is over 15 kV, or gap is outside the range of the model, the theoretically derived Lee method can be applied. The IEEE procedure is valid for voltages ranging from 208V volts to 15kV with gap ranges between 3 mm. The equations are used to calculate the incident energy and arc flash boundary. IEEE Standard 1584 details the procedure and needed equations for arc flash calculations. The boundary is defined by NFPA 70E as the distance at which the worker is exposed to 1.2 cal/cm 2. In addition, a qualified person must accompany unqualified persons. Persons crossing into the arc flash boundary are required to wear the appropriate Personal Protective Equipment (PPE) as determined by calculating methods contained in NFPA 70E. In some instances, calculations may decrease the boundary distance. NFPA 70E also allows the AFB to be calculated. NFPA 70E establishes the default arc flash boundary at 4 feet for low voltage (< 600V) systems where the total fault exposure is less than 5000 amperes-seconds (fault current in amperes multiplied by the upstream device clearing time in seconds). The AFB is a safe approach distance from energized equipment or parts. The arc flash boundary is based on voltage, the available fault current and the time it takes for the upstream protective device to operate and clear the fault. The arc flash hazard analysis should determine the arc flash boundary (AFB) and level of personal protective equipment (PPE) that the worker must wear. It is important to note that conductors and equipment are considered live when checking for voltage while putting equipment in a safe work condition. Until equipment is placed in a safe work condition (NFPA 70E 2000 Part II 2-1.1.3), it is considered live. Also, NFPA 70E 2000 requires that before a worker approaches exposed electric conductors or circuit parts that have not been placed in a safe work condition, a flash hazard assessment must be performed. The limited, restricted and prohibited approach boundaries are based on the voltage of the energized equipment. There are three shock approach boundaries (limited, restricted and prohibited) required to be observed in NFPA 70E 2000. NFPA 70E has developed requirements to reduce the risk of injury to workers due to shock and arc flash hazards.
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