Arc flash working distance

Intensity - How much power the arc has. The working distance is in reference to the arc flash incident energy and it is actually the distance that you are assumed to be standing at while working.

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Arc flash time-current coordination example.

Arc flash working distance. The working distance is in reference to the arc flash incident energy and it is actually the distance that you are assumed to be standing at while working. You see distance is a key component to calculating an arc flash so the engineer needs to make an educated guess as to where someone might be when an arc flash happens. Arc-flash design protection is normally based the incident energy level of the working persons head and torso at the working distance.

Typical working distances can be found in the Table below based on the class of equipment. The working distance is used in calculating the incident energy. Alternate working distances may be used depending on the task being performed.

Classes of equipment and typical bus. This assumes the person is standing at a specific distance from the source of the arc known as the working distance. Depending on the type of equipment this working distance as it is called is typically defined as either 18 or 36 inches however other distances may be used.

Basically the working distance is the distance between you and the point of origin of an arc flash. The point of origin for an arc flash will typically be inside a piece of electrical equipment at an energized conductor or bus. A typical working distance for low voltage equipment might be 18 inches.

To globally change the working distances for several buses highlight the working distance cells in the Arc Flash Evaluation window. Right-click to display the menu and select Global Change. You may now enter a new value for the working distance.

This can only be. An arc flash can cause second- and third-degree burns if the victim is several feet from the arc. Staged tests have shown temperatures of up to 437 degrees F on the hands and neck of an individual standing at a distance of 10 feet from an arc blast.

Or From My HandsWhat part of you is considered the opposite end of the. Working distance inch or mm. The working distance from the arc location.

This field is pre-populated with typical distances from IEEE 1584 2018 which is based on the Equipment Type. The Equipment Type is used to pre-populate the following distances and sizes with typical values from the IEEE 1584 2002. It should be noted that at the normal working distance of 18 inches average arm length of a human the arc flash energy is 48 Calcm2 calories per centimeter squared.

If the worker steps back to a working distance of 48 inches the arc flash energy drops to 12 Calcm2. An arc flash boundary is the distance at which an electrical arc can flash outward and endanger employees working on electrical equipment. Additional boundary requirements include.

Conductive Articles of Jewelry and Clothing. The working distance is an important component of the arc flash hazard analysis and is frequently listed on arc flash warning labels and in the arc flash report. IEEE 1584IEEE Guide for Performing Arc Flash Hazard Calculations 2002 defines the working distance as the dimension between the possible arc point and the head and body of the worker positioned in place to perform the assigned.

Clothing curves based on ARCPRO results with a 4-in 10-cm arc length and a 15-in 38-cm working distance. Arc flash time-current coordination example. As an overcurrent protection problem two related assumptions are made.

1 The incident energy increases linearly with time. If you double the duration the incident energy doubles. Arc-flash protection is always based on the incident energy level on the persons face and body at the working distance not the incident energy on the hands or arms.

The degree of injury in a burn depends on the percentage of a persons skin that is burned. Working distance is described in IEEE 1584 a guide commonly used for performing arc flash incident energy and boundary calculations. IEEE 1584 defines working distance as the dimension between the possible arc point and the head and body of the.

The calculator has limitations. It cannot be applied to every situation is suitable for systems having. Voltage range 50 volts to 30000 volts.

Working Distances between 305 mm and 900 mm. Grounding of all types and Ungrounded. 1 to 250 mm.

Use this convenient tool to view a sampling of arc flash hazard calculations and the impact of various system changes on arc flash energy levels and personal protective equipment PPE requirements. Select the Equipment Type from. Working Distance - Enter the working distance from energized equipment in mm.

Enclosure Type - Enter the enclosure type in which incident energy is calculated. This gives a simple representation of whats involved in arc flash calculations. Always consult with an engineer before doing more complex arc flash calculations.

Incident energy working distance and hazard risk category. Incident energy is the measure of the severity of the hazard to workers. This quantity is defined as the energy density in caloriescm 2 or Joulescm 2 to which the workers face or body is exposed in an arc flash event at the working distance.

The working distance is the typical distance between a potential source of the arc in the equipment. Understanding Arc Flash Simply put an arc flash is a phenomenon where a flashover of electric current leaves its intended path and travels through the air from one conductor to another or to ground. The results are often violent and when a human is in close proximity to.

An arc flash boundary is the distance at which the incident energy equals 12 calcm2 and arc-rated PPE is required for any employee within the arc flash boundary. The working distance is the distance from a persons face and chest to the prospective arc source. Arc Flash Boundary While the other two boundaries deal with shock hazard the arc flash boundary refers specifically to arc flash hazards and explains that 12 caloriescm2 of incident energy is the distance at which a worker will receive second-degree burns in the event of an arc flash incident without appropriate arc rated personal protective equipment.

Determine working distances 7. Calculate arcing current 8. Calculate arc duration through OCPD 9.

Calculate Incident energy IE 10. Determine arc flash boundary for all equipment Note. Blacknew for study engineer Rednew for software Source.

In most cases arc flash incident energy depends on three elements. Intensity - How much power the arc has. This is calculated using the system voltage and the maximum available fault current.

Distance - How far away a from the arc worker will be. Also known as the working distance this measurement is estimated to be 18 inches.