Often when I reiterate that the primary protection scheme must be establishing an electrically work condition (ESWC), a comment is made that a worker is put at risk during this process. The maker of that comment often continues on to defend why they do not require ESWCs in their facility. NFPA 70E® requires that you to conduct risk assessments to determine the hazard, and the risk and severity of possible injury. The standard then requires that you to exhaust the hierarchy of risk controls to protect the worker. This is true whether you intend justify energized work or require that an ESWC be established. If you have determined that there are no hazards, there is nothing to protect the worker from.
If there are hazards, the worker must be protected from injury. Getting to the PPE level in the hierarchy of risk controls means that you have done everything you can to minimize the hazard and the risk of injury. IT DOES NOT MEAN THAT ENERGIZED WORK IS JUSTIFIED. It means that you have determined that there is still a hazard present which requires the worker to wear protective gear when interacting with the equipment under proper justification. The hazard could be shock, arc-flash or both. You will either justify energized work or require that an ESWC be established. I hope the following will clarify the difference of what I mean when an ESWC and justified energized electrical work are mentioned in my blog.
The first reason I make the distinction is for brevity. The reason for and act of establishing an ESWC should be well understood. That a worker is put at risk, must wear protective gear, and must follow work practices are inherently included in this task. To explain this every time is unnecessary. There is no way to establish an ESWC without some risk of exposure to a potential hazard. Until you know for sure that there is no energy present you have to assume that there is energy present. By right, with a proper risk assessment and under the conditions which permit normal operation, establishing an ESWC should remove the hazard before the voltage measurement is made. The ESWC voltage measurement should always be zero. Although establishing an ESWC condition must be considered energized work it actually should not be exposing the worker to an energized circuit. The process is to protect the worker if something has gone wrong.
The second reason is to differentiate between the ESWC tasks and other similar energized work tasks. A voltage measurement may be made for the sole purpose of establishing an ESWC. A voltage measurement may also be made to verify operation of equipment without any intent to put it into an ESWC. Both tasks are exempt from a work permit but there are obvious differences in the two. When establishing an ESWC, the risk of an arc-flash, electrical shock or unanticipated equipment outage is greatly reduced as compared to other tasks. For the ESWC, the worker has limited exposure to the hazard (see first paragraph) whereas for other tasks there is an unlimited exposure to the known hazard or risk of injury. For conditions other than the ESWC the worker is constantly at risk of having an incident occur. Without an ESWC you are using the PPE to protect the worker from a known and present hazard while energized work is being performed. That is a substantial difference from the ESWC task.
The last reason for the distinction is that after the ESWC has been established the worker can remove the PPE. They could conduct the remainder of the work bare handed, wearing every day work clothes without a visibility or hearing impediment. For the other types of energized tasks all the PPE must be worn while the worker is “working” on the equipment (see my two previous blogs regarding the burden of wearing PPE.) The PPE must be worn until the equipment is put back into a normal operating condition. Anyone entering the arc-flash boundary or a shock protection boundary is put at risk and must be protected. The distinction is also made because many voltage measurements for the operation or troubleshooting of equipment evolve into other tasks. Unfortunately this sometimes occurs without generating a new energized work permit covering the new hazard, risk or task. Establishing an ESWC cannot evolve into another task.
I understand that establishing an ESWC is considered to be energized work. Until the task is completed a worker is exposed to hazards and potential injury since there is no assurance that the equipment is properly de-energized. I also understand that establishing an ESWC is justified under infeasibility and that the voltage verification would be included in the work permit exemptions. Up to this point there really is no difference between establishing an ESWC and conducting a voltage measurement. There is a HUGE difference after the voltage measurement is made. Hopefully you see the difference between a worker establishing an ESWC and a worker performing tasks, including other voltage measurements, on energized equipment. Your primary safe work procedure must be to establish an ESWC. Doing otherwise places a worker at risk of injury.
Next time: A rumor that NFPA 70E has a preference on how to conduct a risk assessment.