By Zarheer Jooma, Contributor
Electrical safety-related work practices are governed by different OSHA regulations for utilities, industry, and construction companies. Utilities follow OSHA 1910.269 (Subpart R), industries follow 1910.331 (Subpart S), and construction companies follow a combination of 1926 Subpart K or 1926 Subpart V (depending on the jobsite).
Utilities spend extensive resources on training that ranges from OSHA classes, NESC installations, and company specific procedures. Some of this training spans beyond electrical training and includes non-electrical and human performance type training. In this complex array of training classes, electrical arc-flash safety training may be overlooked or inadequately covered. The lack of adequate training in this field manifests in dangerous situations as we were recently informed of a utility worker that operated a piece of equipment without wearing the proper personal protective equipment (PPE). Although this may not be a problem in certain limited cases, in this instance the label prohibited any energized work based on the (high) arc flash energy. In this case the workers at this utility failed to realize that switching off is considered energized work.
Switching, racking, inspecting, and cleaning are all examples of interacting with energized equipment and present an arc flash hazard. Testing, repairing (maintaining), and grounding are examples of contact (either direct or indirect) and present both a shock hazard and arc flash hazard. OSHA doesn’t require that the hazard never be present, instead it requires the employer to eliminate the hazardous energy as the first option. If eliminating the hazard is not possible, only then can the employer consider the risk of injury and reduce the risk to a tolerable level. Examples of when energized work is permitted includes troubleshooting that requires voltage or when shutting down creates a greater hazard. Also take note that inconvenience or production inhibiting is NOT considered infeasible by OSHA.
Training on the Arc Flash Study
Having served as an independent safety consultant to various utilities has offered a great deal of insight into similar dangerous operating conditions but has also allowed for implementing and testing what works best in these environments. As mentioned above, training is one area that can be overlooked but it is very critical as it will not only provide the instruction and education where needed, it will also provide the awareness so employees can handle these high-risk tasks in a safe and effective manner.
Arc Flash studies are very important for overall compliance but making sure all of your workers clearly understand the results and data that come from the arc flash study is just as critical. Commercial software will assist with arc flash studies such as SKM PowerTools, ETAP, and EasyPower. These are examples that are used for systems less than 15kV, while ArcPro is used for systems above 15kV, such as HV switchyard modeling. Generating plants are fairly complex due to the multiple layers of redundancy in supply and it can be fairly common to find a circuit breaker that is capable of being supplied from four different upstream sources. Engineers undertaking the arc flash hazard analysis need to work with the plant operations and engineering departments to ensure that the correct information is provided for labeling purposes. It is critical to get the labeling correct as these labels will tell workers what PPE is necessary prior to accessing the electrical equipment.
As an example, a switchboard was calculated to be less than 8cal/cm2 when fed from the utility source and required daily wear. This scenario was common to the remaining generating units and operated regularly. In an unlikely event of a total blackout, a black start generator could be used, however, the energy then increased to above 40cal/cm2. The plant decided to utilize the 8cal/cm2 label and drafted a procedure for black start operating. In that procedure the higher arc flash energy is mentioned. In cases like these, OSHA requires emphasizing the major roles played by training. Workers must be trained, the plant must ensure that all workers understand which operating configuration is mentioned in the label, and where to obtain the correct arc flash information if the operating configuration has changed.
No matter what your role may be with a utility, training is crucial. High voltage electricians, linemen, safety directors, utility managers, meter service workers, and underground network linemen can all benefit from the various training offered. Although these are considered specialist positions, there remains areas in which even they require “specialized” training to meet the minimum requirements. Having training that focuses on key areas such as OSHA 1910.269, elements of the arc flash study, consequences of exposure, the selection, care, and application of arc flash PPE, arc flash and shock boundaries, minimum approach distance, locking, tagging, verifying, and grounding of equipment, and hazard identification and risk assessments are all critical areas for utility workers to be always fully aware of. Training will help ensure all personnel are working safe and staying fully compliant.
Zarheer Jooma conducts nationwide electrical safety training and arc flash studies. He joined e-Hazard U.S. after ten years of managing e-Hazard South Africa and many years of experience with Eskom Generation and ArcelorMittal. He has been regarded as the specialist on arc flash safety in South Africa, having convened and chaired SANS 724, the South African national standard for personal protective equipment and protective clothing against the thermal hazards of electric arc. Jooma has extensively researched and published on arc flash incident investigations and how to implement them in industry (https://e-hazard.com/).