Codes and Regulations
IEEE Standard 1584, IEEE Guide for Performing Arc Flash Hazard Calculations: the industry accepted standard in calculating incident energy at a specific location within the power distribution. This method calculates the equivalent arcing short circuit current and uses it to develop the time current characteristic of the overcurrent protective device that would interrupt an arc flash. The arcing current and clearing times are then used in the IEEE 1584 method to calculate the incident energy.
OSHA 29 CFR 1910.132 (d) requires employers to assess the workplace to determine if hazards are present, or likely to be present, and select and have each employee use the types of PPE that will protect them.
OSHA 29 CFR 1910.333 requires employees who are exposed to electrical shock hazard to be qualified for the specific task they are performing. This involves not only safe work practices but using the appropriate Personal Protection Equipment (PPE).
OSHA 29 CFR 1910.335 (a)(1)(i) states that employees working in areas where there are potential electrical hazards shall be provided with, and shall use, electrical protective equipment that is appropriate for the specific parts of the body to be protected and for the work to be performed.
OSHA 29 CFR 1910.335 (a)(2)(i) states that when working near exposed energized conductors or circuit parts, each employee shall use insulated tools or handling equipment if the tools or handling equipment might make contact with such conductors or parts. If the insulating capability of insulated tools or handling equipment is subject to damage, the insulating material shall be protected.
OSHA 29 CFR 1910.335 (a)(2)(ii) states that protective shields, protective barriers, or insulating materials shall be used to protect each employee from shock, burns, or other electrical related injuries while the employee is working near exposed energized parts which might be accidentally contacted or where dangerous electric heating or arcing might occur. When normally enclosed live parts are exposed for maintenance or repair, they shall be guarded to protect unqualified persons from contact with the live parts.
NEC® 110.16 states that equipment must be marked to warn qualified persons of potential electrical Arc-Flash Hazards. “Switchboards, Powerboards, Control Panels and Motor Control Centers shall be field marked to warn of potential arc flash hazards”.
NEC® 110.9 states that the equipment intended to interrupt current at fault levels shall have an interrupting rating sufficient for the nominal circuit voltage and the current that is available at the line terminals of the equipment.
NEC® 110.10 states that the electrical characteristics of the circuit must be known to properly select and coordinate protective devices used to clear a fault. The characteristics of the system are source impedance, individual component impedances, connected loads, and short-circuit current ratings. Protective devices must be coordinated so as to protect people, equipment, and isolate the least affected part of the system.
NFPA-70E® 2015 Standard for Electrical Safety in the Workplace, Article 130.5 states “An arc flash hazard risk assessment shall be performed and shall:
- Determine if an arc flash hazard exists. If an arc flash hazard exists, the risk assessment shall determine:
- Appropriate safety-related work practices
- The arc flash boundary
- The PPE to be used within the arc flash boundary
- Be updated when a major modification or renovation takes place. It shall be reviewed periodically, at intervals not to exceed 5 years, to account for changes in the electrical distribution system that could affect the results of the arc flash risk assessment.
- Take into consideration the design of the overcurrent protective device and its opening time, including its condition of maintenance.”