Arc Flash Label Requirements are specified by NFPA 70E, which details how to comply with the OSHA 29 CFR 1910.333(a) regulation. Applying these electrical safety standards in the workplace serves to protect electrical workers around energized electrical equipment with the potential electrical hazards to generate an arc flash explosion.
An arc flash label is used to alert workers of potential arc flash explosion and electrical shock hazard. The Arc Flash label is imprinted with important safety information about the type of threat or hazard in question, so qualified electrical workers can either avoid this area or make sure they understand what minimum arc rating is, and they are wearing the personal protective equipment (PPE) before accessing equipment or stepping inside the arc flash boundaries.
Arc Flash Label Requirements
1. Incident energy
Incident energy, as indicated on the arc flash label, is the level of thermal energy that one would feel at the working distance in the event of an arc flash. This energy is measured in calories per centimeter squared. Commonly noted as cal/cm2.
2. Arc Flash Boundary
The Arc flash boundary is the distance from a possible arc source to where the incident energy drops to 1.2 calories per square centimeter. If a person were standing at this distance from the arc source, they could receive a second-degree burn.
3. Available fault current
The amount of current supplied by the electrical equipment’s upstream device.
4. Recommended PPE
A recommended list of shock and arc flash hazard PPE that shall be worn when performing safe work on equipment that is not placed in an electrically safe condition.
5. Working Distance
The working distance is the distance at which the incident energy is calculated. IEEE 1584 a guide commonly used for performing arc flash incident energy and boundary calculations, 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 task.”
6. Nominal System Voltage
Nominal voltage is a value assigned for conveniently designating a voltage class, such as 120/208V, 277/480V. Many electrical workers have been injured because they used test equipment rated for 1,000 volts on circuits energized at 4,160 volts or higher.
7. Glove Class
Workers must be protected from shock by wearing rubber insulating gloves if their hands enter the restricted approach boundary. Workers must select gloves that have a rating for the level of voltage to which the gloves will be exposed.
8. Limited Approach Boundary
The limited approach boundary is designed to keep unqualified workers safe from shock hazards. Unqualified worker can only cross this boundary if he or she is continuously escorted by a qualified worker.
9. Restricted Approach Boundary
Only qualified persons may cross into the restricted approach boundary. Inside this boundary, accidental movement can put a part of the body or conductive tools in contact with live parts.