Electrical safety audits can be utilized in industrial facilities to identify hazards, review protective equipment and determine if the electrical system is compliant with applicable requirements. Understanding the risks involved with arc flash incidents is a major aspect of this preparation. The heat, light and pressure generated by an arc flash can cause serious injury and damage. An arc flash study can be performed to determine these risks, determine the incident energy levels, and then adopt suitable protection before any electrical maintenance or inspection work is done.
1.Check Your Electrical System Data.
To make the assessment of safety meaningful, the information about the electrical systems is required to be accurate. Prior to an audit, facilities should check their electrical drawings, equipment specifications, and check records of past changes.
Important information includes:
- Single line diagram of electrical distribution network.
- Details on transformer ratings, cable information and equipment specifications.
- The settings for circuit breakers and protective relays.
- How to obtain short-circuit current data, if available.
- Documentations of electrical system upgrades and maintenance.
The reliability of the assessment may be compromised by old drawings and/or the incorrect information on equipment. These records can be a great benefit in determining an accurate representation of the electrical network by engineers.
2. Assess Arc Flash Risk
An arc flash study involves consideration of the possibility of an arc flash occurring at a specific piece of electrical equipment and the estimation of the incident energy if an arc flash does occur under specific operating conditions. This information is used to estimate the risk to which a worker can be exposed when undertaking certain electrical activities.
Typically, the available fault current, device clearing time, equipment characteristics and distances are taken into account. These factors will affect the severity of an arc flash event.
It is important that before an electrical audit is conducted, the facility management personnel have verified that the assessment includes the necessary equipment and is based on the current electrical system configuration. The outcomes can be used to pinpoint areas where extra risk controls could be required.
3. Inspect Protective Devices and Coordination
Protective devices like circuit breakers or relays can help to reduce fault duration. If they run slow or if they are not set up properly, incident energy can be raised.
Check protective device settings and ensure they are consistent with approved coordination study and equipment configuration. When looking at the assessment, it is important to take into account any changes to transformers, switchgear or electrical distribution arrangements.
Short circuit analysis and protective device coordination are inputs that are crucial to an Arc Flash Study as it relies on accurate fault currents and realistic device operating times.
4. Check Arc Flash Labels and Safety Procedures
Electrical safety audits can assess a worker’s ability to identify hazards and to take proper safety precautions. Labels for arc flash should provide meaningful arc flash hazard information based on the applicable arc flash boundary or incident energy, as determined by the applicable arc flash assessment method and standard.
Verify that labels are available and are legible and do not conflict with the latest research findings. Check electrical work procedures, access limitations, training records and training requirements for appropriate personal protective equipment (PPE).
An employee should know what to read on labels and be familiar with safety practices. Labels cannot substitute for safe work practices and don’t remove hazards.
5. Maintain documentation and assessments.
A safety audit can also help outline areas for document deficiencies and follow-up activities. Keep study reports, electrical drawings, equipment data, protection settings and corrective measures reports in an accessible area.
Re-evaluate study when major changes are made in electrical systems or when applicable standards and assessment requirements for the study dictate it. Review time is dependant on the governing requirements and system changes and site conditions.
Conclusion
Knowing how to prepare for an electrical safety audit is a much bigger task than inspecting equipment and paperwork. Accurate electrical system data, reliable hazard assessments, appropriate settings and clear procedures for protective devices are necessary for facilities. An arc flash study helps this process by enabling engineers to identify potential hazards and make recommendations for appropriate risk control measures. When combined with study and maintenance records, labels, and operating procedures, these can assist facilities in identifying gaps prior to an audit and help to create a safer working environment for electrical personnel.
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