Last August I wrote a blog about using the hierarchy of risk controls when the policy is to establish an electrically safe work condition (ESWC). That blog closed out by asking why go through the additional steps of the hierarchy when the hazard will be removed. The example provided was that I am aware of situations where equipment has an incident energy higher than what currently available PPE is rated to provide protection from. Hopefully, this situation will not occur at your facility for any newly installed equipment since you plan to address this hazard early on. But I have been asked what should be done in the cases where equipment is already installed and installation practices cannot be employed to reduce the hazard or risk. In other words elimination, substitution and engineering controls from the hierarchy cannot be employed (at this time.) The work has to be conducted but it is not possible to safely establish an ESWC.
Many simply use the “theory” that since the policy is to eliminate the hazard through an ESWC that the hierarchy need not be used to lower the risk or hazard. The equipment is installed and nothing can be done regarding the installation. They will use this “theory” every time the employee is put at risk of injury performing that same task on that installed piece of equipment. Safe installation and normal operation of the equipment does not have a limit on the voltage, current, or energy levels present in that equipment. Those levels are generally a concern once an employee is exposed to them under conditions that are not normal operation. After all these years I do not condone ignoring electrical safety of the employee during design and installation. Every case is different and this blog should in no way be used as a basis for a policy. Some of the examples may seem extreme but remember, this is about not injuring the employee. This will discuss establishing an ESWC when hazards are excessive since very few situations actually qualify as justified energized work.
If the work can be delayed, a full electrical shutdown by the utility during a facility closure is an option. Even if the facility does not normally close there may be slow times when it is ideal to have the electric supply removed to protect the employee. The utility has policies, practices and procedures that deal with electrical hazards beyond what is typically present on the load side of the service point. Remember this is for the purpose of establishing an ESWC. This typically does not take days or even hours. Once the ESWC is established for that equipment, the remainder of the facility could be brought back online. If this is not an option, the individual equipment may provide guidance on how to perform the task. All loads should be removed. Although non-contact methods are not permitted to verify an ESWC at lower voltages, they may be used to indicate that the voltage has not been properly interrupted thereby avoiding an unexpected outcome. Higher incident energies may also be associated with higher voltages where non-contact methods are acceptable. With arc-flash boundaries at higher incident energies often exceeding 10 feet, it is difficult to remain outside the arc-flash boundary when verifying an ESWC. However, it may be possible to use probes while not standing directly in front of the equipment and away from the arc-flash direction. This could be via remote control or special probes. It may be possible to design a mobile arc-flash barrier to allow closer approach while verifying the ESWC. I would brainstorm solutions with a group. I would exhaust all possible ideas, concepts, and approaches to verifying the ESWC in these cases. I would not condone having an employee don an 80 calorie rated suit while subjected to a possible 200 calorie incident energy. Whatever solution I came up with to deal with this situation, I would probably perform the task myself. If I was not comfortable with the solution I would never put another person at risk.
This goes back to my blog discussing installation and electrical safety of future employees. These should not be independent considerations. I would use this out of the ordinary solution once. Now is the time to use the hierarchy of risk controls to mitigate this dangerous situation in the future. As a safety professional I would feel obligated to better protect the employee the next time this task must be conducted. This may involve modification of the installation. If not now, when? It would be remiss to not correct a known hazard exposure for the employee. At the very least, I would work to have the voltage and incident energy values lowered to ones where appropriate protection is available. At the best, I would strive to have the levels lowered to the least practicably possible. I might also consider installing a permanently mounted test device.
No matter what you decide to do in these situations consider the outcome. If an employee is injured or killed under the current policy permitting high incident energy levels, how will you justify why you had them do what they did? If an injury happens the third or fourth time that you expose them to these elevated levels, what will be your reason for not addressing it the first time? For that matter, you might want to use this concept anytime an employee is put at risk. What will you say you did to protect that employee from a hazard you had the possibility of mitigating?
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