2/20/2023 0 Comments Arc flash boundary![]() ![]() The only practical way of determining this boundary is to calculate the magnitude of the arc (a function of the available short circuit current), estimate how long the arc will last (a function of the interrupting time of the fuse or circuit breaker), and then calculate how far away an individual must be to avoid receiving an incident energy of 1.2 cal/cm2. This distance (boundary) cannot be determined by casual survey of electrical equipment. Research has shown that permanent injury results from an arc-flash that causes an incident energy of 1.2 calories/centimeter2 (cal/cm2) or greater at the skin's surface. ![]() The arc-flash boundary is a distance at which a person working any closer at the time of an arc-flash may receive permanent injury (the onset of a second degree burn or worse) if not properly protected by flame-resistant (FR) clothing. Equipment energized below 240V need not be considered unless fed by a 112.5KVA transformer or larger. This includes conducting activities such as examination, adjustment, servicing, maintenance or troubleshooting. Arc-Flash BoundaryĪrc-flash boundaries are required around electrical equipment such as switchboards, panelboards, industrial control panels, motor control centers, and similar equipment when an individual works on or in the proximity of exposed energized (energized and not enclosed, shielded, covered, or otherwise protected from contact) components. Although 70E does not explain how to conduct an analysis it does say the analysis shall determine a flash protection boundary and the personal protective equipment (PPE) requirements when working within that boundary. On the subject of arc-flash, 70E requires a flash hazard analysis. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |