You see, distance is a key component to calculating an arc flash, so the engineer needs to make an educated guess as to where someone might be when an arc flash happens. The working distance is in reference to the arc flash incident energy and it is actually the distance that you are assumed to be standing at while working. If the engineer followed the recommendations in CSAZ462 workplace electrical safety then each label should have listed the working distance, arc flash boundary, limited approach boundary, and the restricted approach boundary. Most industrial facilities have gotten around to completing an arc flash incident energy analysis and posted labels (or stickers) on all of the electrical equipment. In this article, we will go over what each of these distances actual mean and why they are important to you or anyone who is working on or near exposed energized electrical parts.
In fact, if they are ignored or misinterpreted then the risk of injury is definitely going to go up. In my experience, these distances seem to take a back seat to the incident energy level of an arc flash or the voltage level of a potential shock hazard but they are critical in determining one's safety. If you work with electricity then you are probably well aware of the hazards (arc flash and shock) but something you might not be so comfortable with is the safe limits of approach and what is referred to as the working distance.
