This boundary is determined by NFPA 70E Table 2-1.3.4 (2000 Addition) and is based upon the voltage of the equipment.Ĭircuit Breaker - A device designed to open and close a circuit by non-automatic means and to open the circuit automatically when a predetermined over current occurs without damage to itself when properly applied within its rating.ĭead Front - Without live parts exposed to a person on the operating side of the equipment.ĭisconnecting Means - A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply.Įlectrical Hazard - A dangerous condition such that contact or equipment failure can result in electric shock, arc flash burn, thermal burn or blast.Įxposed (as applied to live parts) - Capable of being inadvertently touched or approached nearer than a safe distance by a person. Therefore, personnel must obtain a risk assessment before the prohibited boundary is crossed. Only qualified personnel wearing appropriate personal protective equipment (PPE), having specified training to work on energized conductors or components, and a documented plan justifying the need to perform this work may cross the boundary and enter the Prohibited Space. Prohibited Approach Boundary-A shock protection boundary to be crossed by only qualified persons (at a distance from a live part) which, when crossed by a body part or object, requires the same protection as if direct contact is made with a live part. This boundary is determined from NFPA Table 2-1.3.4 (2000 Edition) and is based on the voltage of the equipment. Also, he must have a written approved plan for the work that they will perform and plan the work to keep all parts of the body out of the Prohibited Space. To cross the Restricted Approach Boundary into the Restricted Space, the qualified person, who has completed required training, must wear appropriate personal protective equipment (PPE). Restricted Approach Boundary-A shock protection boundary to be crossed by only qualified persons (at a distance from a live part) which, due to its proximity to a shock hazard, requires the use of shock protection techniques and equipment when crossed. No untrained personnel may approach any closer to the energized item than this boundary. The limited approach boundary is the minimum distance from the energized item where unqualified personnel may safely stand. Limited Approach Boundary - a shock protection boundary to be crossed by only qualified persons (at a distance from a live part) which is not to be crossed by unqualified persons unless escorted by a qualified person". Arc rating is normally expressed in cal/cm2. This guidance should be used unless there is a detailed arc hazard analysis and Hazard Mitigation Plan that has calculated arc flash energy and established PPE requirements for the specific equipment being worked on. Equipment has started to be labeled with a label such that pictured below (note: This is an on going labeling process by FOC and not all equipment has been labeled as of today).Īrc Rating - The maximum incident energy resistance demonstrated by a material (or a layered system of materials) prior to break open or at the onset of a second-degree skin burn. Refer to NFPA 70E for additional information. This document will summarize key provisions of NFPA 70E as they apply to work conducted by SUNY NP FOC employees. This guidance is derived from the National Fire Protection Association's (NFPA) recommended standard NFPA 70E, Standard for Electrical Safety in the Workplace. With sufficient energy, an arc flash may become an arc blast producing a dangerous shock wave. The magnitude of the energy and other factors will determine the severity of the arc flash. Occurring in a fraction of a second, it produces a brilliant flash, intense heat, and a shock wave. The arc flash creates electrically conductive superheated plasma that can reach temperatures of 5000° F and above. An arc flash may also occur during movement of energized electrical contactors, such as switches. PPE is not required when in proximity to electrical equipment in enclosed panels with no exposed connectors, where electrical work is not being performed and where no high voltage switch is being operated.Īn arc flash may occur when electrical current "short circuits," that is, flows from energized wires or equipment to ground, or between energized wires or equipment with different phases or potential. This guidance applies to situations in which staff may be exposed to arc flash from high voltage switches or live unguarded electrical wires, parts or equipment with voltages above 50 Volts. This guidance document provides guidelines on selection of Personal Protective Equipment (PPE) for protection from electric arc flash from equipment for which detailed arc hazard analysis has not been performed.
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