What is an arc flash study?
IEEE 1584 and NFPA 70E, in plain terms
The problem an arc flash study solves
An arcing fault releases explosive energy — heat, pressure, molten metal. An arc flash study calculates how much of that energy a worker would be exposed to at each piece of equipment, so the hazard is known, labeled, and planned for before anyone opens a panel. NFPA 70E requires an arc flash risk assessment as part of an electrical safety program, and the calculations follow IEEE 1584.
What the work actually involves
- Data collection — utility fault contribution, transformer and conductor data, protective device types and settings. Much of it comes from drawings and photographs; field verification is planned around your operations.
- System model — a short-circuit and protective-device-coordination model of the studied system.
- Incident energy calculations — energy and arc flash boundary at each studied bus, per IEEE 1584.
- Labels — print-ready warning labels with incident energy, boundary, and PPE requirements.
- Recommendations — often, protective device setting changes that reduce the hazard without replacing equipment.
Questions we hear most
Is it required by law? OSHA requires employers to protect workers from electrical hazards; NFPA 70E is the consensus standard used to meet that duty, and it calls for the risk assessment. Many owners and insurers simply require the study outright.
How often does it need updating? NFPA 70E calls for review at intervals not exceeding five years, and sooner when system changes — a new transformer, different utility fault data, revised settings — could affect the results.
What does one cost? Ask the site assistant for the current unofficial planning range, or read how the planning estimate works. The actual fee depends on the number of buses studied and the state of your documentation.
This page is educational. It is not engineering advice for your installation, and it is not legal advice — practice acts and code requirements change, and the authority having jurisdiction decides how they apply to a specific project.