Summary
Arc Flash is a sudden release of energy caused by an electrical fault. It can generate intense heat, light, pressure, sound, projection of materials and serious risks to people and equipment.
What is an Arc Flash
An Arc Flash occurs when an electrical current circulates through air between energized conductors or between a conductor and ground. This phenomenon can occur during failures, maneuvers, maintenance, insulation deterioration or operational errors.
It should not be seen only as an “electrical explosion.” Technically, one of the most important concepts is the incident energy, which represents the thermal energy that a person located at a certain distance from the arc could receive.
Typical causes
An Arc Flash can be caused by:
- Insulation failures.
- Poorly used tools.
- Dust, humidity or contamination.
- Animals or strange elements on boards.
- Poor maintenance.
- Errors during maneuvers.
- Loose connections.
- Deteriorated equipment.
- Internal short circuits.
Incident energy
Incident energy is normally expressed in cal/cm². The higher it is, the greater the risk for the worker and the greater the protective measures required.
The value depends on variables such as fault current, arc current, clearance time, working distance, type of equipment, voltage level, cabinet configuration and protection settings.
Arc Flash Limit
The Arc Flash limit is the distance from which the incident energy decreases to a level defined by the methodology used. This limit helps establish work zones and safety requirements.
Relationship with short circuit and protections
An Arc Flash study is not done in isolation. First, it is necessary to know the electrical system, calculate short circuit levels and review the operating times of the protections.
Coordination of protections is especially important, because clearance time directly affects incident energy.
What is an Arc Flash studio for?
A study allows:
- Calculate incident energy.
- Determine limits of approach.
- Define warning labels.
- Review PPE requirements.
- Identify areas of greatest risk.
- Evaluate mitigation measures.
- Improve work procedures.
- Train staff.
Risk reduction measures
Some possible measures are:
- Reduce clearing times.
- Use maintenance modes.
- Implement relays with fast detection.
- Apply interlocks.
- Remotely operate certain equipment.
- Perform preventive maintenance.
- Update old boards.
- Limit energized work.
common mistake
A common misconception is that studying Arc Flash is just about sticking labels on boards. Labels are important, but they are the visible result of deeper technical analysis.
Conclusion
Arc Flash is a technical and human risk. Evaluating it allows you to protect people, improve operational safety and reduce equipment damage.
The Arc Flash assessment transforms an invisible risk into concrete information to operate, intervene and maintain facilities with greater control.
If you need to evaluate electrical risks, protections and operating conditions to reduce exposure to Arc Flash, review our service. study and review of projects and built electrical networks.