To help facilitate adequate planning, budgeting, and implementation, Elara Engineering would like to inform owners and managers of all building types, including commercial, industrial, and educational, of existing NFPA Electrical Code and OSHA requirements to properly label regulated electrical equipment about Arc Flash hazards.
Although required, Elara has observed buildings that may not have proper labeling to inform workers of an Arc Flash hazard and what type of Personal Protective Equipment (PPE) is needed before opening or operating electrical equipment.
What is an Arc Flash?
- An Arc Flash is a sudden, powerful release of electrical energy through the air, typically between two conductors or a conductor and ground.
- It’s caused by a fault in the electrical system, such as a short circuit, that allows the current to flow through the air instead of its intended path.
- Potential root causes of the fault include:
- Electrical equipment failure due to moisture content, damaged or degraded insulation.
- Poor maintenance of electrical equipment.
- Unsafe work conditions.
What Will Happen?
- Severe Burns: Extreme heat and light can ignite clothing and cause severe burns to the skin.
- Fire: The intense heat can start fires.
- Arc Blast: The rapid expansion of air and vaporization of materials can create a Pressure Wave (Arc Blast), causing physical injuries and damaging equipment.
- Eye Damage: The intense ultraviolet light can damage eyesight.
- Hearing Damage: A loud explosion can damage hearing.
How can it be Prevented?
- Safety measures include using the proper personal protective equipment (PPE) as indicated by the Arc Flash warning label.
- Safe work practices.
- Preventive maintenance and proper maintenance of electrical equipment.
Applicable Electrical Codes and Rules
- NFPA 70, Sections 10.16 and 130.5.H
- OSHA Rule, 29 CFR Parts 1910 & 1926
Arch Flash Warning Label
The following minimum information is required in each Arc Flash warning label:
- Nominal System Voltage
- Arc Flash Boundary
- Available Incident Energy and the Corresponding Working Distance
- The Arc Flash PPE Category
- Minimum Arc Rating of Clothing
- Site Specific Level of PPE
What Should Building Owners do Next?
Elara Engineering suggests that building owners/managers work with a qualified electrical engineer and electrical contractor to perform the requisite study to identify regulated electrical equipment within their building, calculate the Arc Flash Energy of each piece of equipment (see next section to see what the study entails), and develop the appropriate Arc Flash labels for application.
What is Needed to Calculate Arc Flash Energy?
To calculate Arc Flash energy, the following two calculations are required:
- Short circuit
- Circuit breaker or fuse protection coordination
The following information is required to perform the above calculations:
- Available fault current information from the utility company.
- Each service conduit and wire size, conduit material, and total length.
- Each feeder conduit and wire size, conduit material, and total length.
- Each switchboard and panelboard circuit breaker or fuse size and type.
- A complete building single-line diagram.
For more information about Arc Flash hazards, proper labeling, and ways to facilitate a path toward compliance please reach out to Bhupendra Tailor (btailor@elaraeng.com).
Bhupendra Tailor
Principal
Electrical Practice Leader
btailor@elaraeng.com
