Outer-layer garments worn over arc-rated clothing must also be arc-rated.

• A. True
• B. False
• C. Not Applicable
• D. Only when rain gear is worn

Answer: (A)

The protection from arc-rated clothing comes from the entire clothing system, not just the base layer. An arc flash can cause fabrics to ignite or melt, and the heat transfer can go through or around inner layers if an outer layer isn’t arc-rated. If you wear arc-rated underwear or underlayers with a non-arc-rated outer garment, that outer layer can ignite or fail, compromising the whole protection level. Therefore, any outer garment worn over arc-rated clothing must also be arc-rated to preserve the intended protection of the ensemble. This applies regardless of weather—outerwear should be arc-rated when used in an arc flash hazard area.