Energized Electrical Work
Electrical Qualified Persons
Only “qualified persons” may work on or near exposed energized electrical systems or conductors. Unqualified persons assisting in the work must be under the direct supervision of a qualified person for the duration of the exposure.
The routine acceptance of working a system energized should not be a risk that Virginia Tech, the department, the electrical worker, or anyone else routinely accepts. Energized parts greater than 50 volts to which an employee might be exposed shall be put into an electrically safe work condition before an employee works on or near them, unless work on energized components can be justified.
Note: Tasks that are considered to be diagnostic in nature (i.e. troubleshooting or testing where the equipment/system must be energized in order to perform such tests) are considered to be justified by their nature and do not require documentation via the Energized Electrical Work Assessment. Safe work practices, including appropriate personal protective equipment and tools as determined by the hazard analysis, must be used.
Work that is not diagnostic in nature, where the equipment or system cannot be put into an electrically safe work condition, must be justified in writing via the Energized Electrical Work Assessment . Justification means that the employer can demonstrate that de-energizing introduces additional or increased hazards, or is infeasible due to equipment design or operational limitations. A qualified person may perform work on or near exposed live parts under the following conditions:
- De-energizing the conductors or equipment would result in an increased or additional hazard. Examples include: the loss of electrical power to life support equipment, loss of electrical power which could result in an environmental spill, deactivation of emergency alarm systems in an occupied building, or the shutdown of hazardous location ventilation equipment that is in use.
- Note: Lack of illumination is not justification for live work. Temporary lighting must be installed, where necessary.
- De-energizing the conductors or equipment is infeasible due to equipment design or operational limitations. Examples include: performing diagnostics and testing (e.g. start-up or troubleshooting) that can only be performed with the circuit energized, or work on circuits that form an integral part of a continuous process that would otherwise need to be completely shut down in order to permit work on one circuit or piece of equipment. This condition is typical of chemical processing plants.
There is a significant difference between infeasible and inconvenient, and the two terms should not be used interchangeably. Inconvenience cannot serve to justify work on or near exposed live parts.
- Note: For voltages less than 50 volts, the decision to de-energize should include consideration of the capacity of the source and any overcurrent protection between the energy source and the worker. Sources of electrical energy less than 50 volts can be hazardous, for instance, control circuits that operate at less than 50 volts could impact process conditions and result in a release of another kind of energy. Even if the capacity of the energy source is limited, the integrity of the circuit could be critical.
Energized Electrical Work Assessment
Experience suggests that if managers and supervisors are advised that a significant risk of injury exists, they are reluctant to accept that increased risk, and he or she will be more critical of the plan to execute the work. An Energized Electrical Work Assessment must be completed for all work on or near exposed electrical conductors greater than 50 volts, with the exception of diagnotic testing as described above, where an electrically safe work condition cannot be established. This assessment provides guidance on required analysis and establishes written justification and authorization for live work. It also provides a means of communication between the supervisor and the employees performing the work. View the flow chart for more information.
Elements of the Work Assessment
Section I - Work Request: This section is to be completed by the department being requested to perform the work live. (Typically, a Work Order will be requested of Facilities stating the scope of the work and a request to perform it live. The department who will be conducting the work will then initiate the Energized Electrical Work Assessment.) It must provide a description of the circuit and equipment to be worked on and its location. It also indicates that the equipment has been requested to be shut down, either until the work has been completed or temporarily while barriers are installed.
Section II - Hazard Analysis: This section is to be completed by the electrical qualified person who will be performing the live work. It includes detailed information regarding the hazards expected to be encountered and protective measures that must be implemented prior to beginning work.
- Results of the shock hazard analysis - A shock hazard analysis determines the voltage to which personnel will be exposed, the boundary requirements, and the personal protective equipment necessary to minimize the possibility of electrical shock. As voltage increases, so does the degree of risk.
- Results of the flash hazard analysis - A flash hazard analysis determines if flame-retardant clothing must be worn by the worker (and the appropriate rating of the clothing), and the location of the arc-flash boundary. If the flash hazard analysis suggests that the intensity of the arc flash could expose a worker to 40 calories per square centimeter (cal/cm2), the work must not be performed unless an electrical safe work condition has be established. If the intensity is greater than 40 cal/cm2, no protective equipment exists that can protect the worker from the intense pressure that also will be produced by the arcing fault.
Section III - Review of Proposed Energized Electrical Work: Once the electrical qualified person has signed the Hazard Analysis section indicating that live work is requested and justified, final review must be performed by the supervisor, designated safety representative, and departmental management. (Where the department does not have a designated safety representative, contact EHS.)
If review signatures are not obtained for all three levels, or if all parties are not in agreement, the request to work live is denied. The work must then be performed in an electrically safe work condition (i.e. de-energized) and the date and time for shut down must be coordinated between the department and the electrical qualified person(s) performing the work.
Note: As tasks are evaluated (i.e. an Energized Electrical Work Assessment is completed), file them for future reference so that the information can be used again, provided the work task conditions remain consistant.