Arc flash boundary vs limited approach boundary Two, add some distance to whatever the label says because I wouldn't want anyone standing where they can get a second-degree burn. One, set up barricades to keep bystanders outside of the arc flash hazard boundary limits. There are two important takeaways from this. They used to call it the arc flash protection boundary until someone pointed out that it did not protect anyone from anything (well maybe third-degree burns).īut how do you determine the arc flash boundary? This is where an arc flash study comes in, a study will highlight on each piece of equipment the exact distance to be away from in order to setup the correct arc flash boundary marking.

The arc flash boundary is the distance away from an arc flash where someone would be able to receive a second-degree burn. just kidding) then you would be exposed to an arc flash of much less magnitude. The important thing to remember is that if you were working on a piece of equipment and you were closer than the assumed working distance you would be exposed to a greater arc flash incident energy level than what is posted on the label.Ĭonversely, if you were able to take a few steps back from the equipment and continue your work (maybe with a broomstick.

Since most arc flashes occur when someone is performing work on a prospective piece of equipment it only makes sense to calculate the arc flash at that assumed working distance. 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.

So what is arc flash working distance? 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 following: The CZA Z462 :21 Table 1A is a great resource for both a restricted approach boundary table and a limited approach boundary table. 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.

The Arc Flash Protection Boundary