Arc flash labels must be placed on any piece of electrical equipment where workers might need to perform work while the equipment is still energized. This typically includes equipment such as Panelboards, Switchboards, MCCs, etc.
Arc Flash Label Format
Label format should conform to the ANSI Z535.4 Products Safety Signs and Labels standard requirements, which include the WARNING or DANGER signal word and corresponding colors, symbols, and text. Generally, WARNING (with an orange background) is used for arc ash labels to indicate a serious hazard exists. The term DANGER should only be used when a life-threatening situation is imminent; sometimes businesses use DANGER when the incident energy is higher than 40 cal/cm2.
Label Field Details
The following fields are required to be shown on the arc flash label. Arc flash calculation and related fields are calculated per IEEE 1584-2018.
Incident Energy and Working Distance: Incident Energy is a measure of thermal energy at a working distance from an arc fault (measured in cal/cm2). The working distance is the distance from where the worker stands to the flash location.
OR PPE Category: The Arc Flash PPE Category is determined by consulting the PPE tables in Article 130.7 of NFPA 70E. PPE categories range from 1 to 4 (with four having the highest incident energy rating and requiring the most protective gear). PPE Category is not depicted on this sample label because the available incident energy and corresponding work distance are listed. Both cannot appear on the same label.
Arc Flash Boundary: An approach limit located at the distance from exposed live parts within which a person could receive second-degree burns if an arc flash occurred.
Shock Hazard/Nominal System Voltage: Shock Hazard, measured in VAC, is a dangerous electrical condition associated with the possible release of energy caused by contact with or approach to energized parts. This number also represents the nominal system voltage and could be labeled as such.
Glove Class: Electrical safety gloves are categorized by the level of voltage protection they provide and whether they’re resistant to ozone. Voltage protection is broken down into six classes. Class 00 is the least protective, while class 4 provides the most protection.
Assessment Date: Arc flash risk assessments must be reviewed at least every 5 years or when a major modification occurs. Including a documented date is helpful for this reason.
Arc Flash & Shock Approach Boundaries
While the Limited Approach and Restricted Approach boundaries listed on the sample label do not apply directly to arc flash, it is helpful to see where these boundaries are located. Any workers who must enter these boundaries should receive appropriate training and wear required protective equipment. Depending on the situation, the arc flash boundary can be located inside or outside the limited approach boundary.
Limited Approach: The Limited Approach Boundary indicates where an electric shock could occur. It should be entered only by qualified persons or unqualified persons that have been advised and are escorted by a qualified person.
Restricted Approach: A heightened risk of electric shock exists inside the Restricted Approach Boundary. Only qualified persons should enter this space. Requires the use of shock protection techniques and PPE.