Electrical workers are required to wear arc rated/flame resistant clothing when doing energized electrical work. A majority of workers wear AR/FR pants with long sleeved shirts tucked into the pants. However, some workers prefer wearing AR/FR bib overalls with an AR/FR long sleeved shirt. This leaves open the question of whether it matters if the shirt is worn underneath or over the bib overalls. The new 2015 NFPA 70E will have a requirement to tuck the shirt into the pants but the wording will not likely cover a bib overall.
It is important to consider two factors when deciding whether or not to tuck the shirt into the bib overalls when working in an energized electrical environment.
First, the worker may be wearing an AR t-shirt tucked into the bib and adding a long sleeved shirt when working in an energized area. If this is the case, it probably doesn’t make a difference whether the shirt is tucked in or not. The energy coming up under the shirt would likely hit the bib and if it came up from the back would not ignite the t-shirt.
Second, the worker could be wearing a non-FR t-shirt or no t-shirt at all under the bib, with the long sleeved shirt over the bib for energized work. This is a different animal. Here, the t-shirt can possibly ignite if energy comes underneath, or the skin can be burned from energy under the shirt. This is less likely in the front than in the back. While this might not be specifically mentioned in the new rules, it is something to consider when working in an electrically energized environment.
Regarding t-shirts, it is important to note AR t-shirts pose a low risk if any at all. However, non-AR t-shirts pose a little risk but less with bib overalls than with pants. In training we remind workers to “Tuck, button and roll down the sleeves before doing energized work. This will reduce the risk of ignition of undergarments and protect better than allowing energy under a shirt in those odd circumstances.