This week’s question is part of the ongoing series about trust/confidence with various electrical protection equipment/scenarios. Here comes another one.

It is about how confident are you that arc rated clothing/PPE will protect the worker as expected in the event of an arc flash? This question assumes everything has been correctly selected.

There may be additional factors to discuss regarding this subject such as hands or other parts of the body being closer than the working distance, etc.

Here is this week’s question:
How confident are you that arc rated clothing/PPE will protect from an arc flash as expected?
-High Confidence
-Moderate/Reasonable Confidence
-Low Level of Confidence
-Not at all

If we look at ASTM F1959 - [2014] Standard Test Method for Determining the Arc Rating of Materials for Clothing, 3.1.7, the arc thermal performance value of clothing materials corelates with a 50% probability that sufficient heat transfer though the material is predicted to cause the onset of 2nd degree skin burns, ... So I guess I should be 50% confident that my 12 cal shirt will protect me from a 12 cal exposure, and 50% confident that the same exposure will cause 2nd degree burns.