What feature must all clothing used for arc flash protection possess?

All clothing used for arc flash protection must possess the feature of being arc-rated. This means that the clothing is specifically tested and certified to provide protection against the thermal effects of an arc flash, which can generate extreme heat and can potentially cause serious injuries. Arc-rated clothing is designed to prevent igniting and to insulate the wearer from the intense heat produced during an arc flash incident.

The arc-rating is quantified in terms of ATPV (Arc Thermal Performance Value) or EBT (Energy Breakopen Threshold), which indicates the level of protection afforded by the fabric. This is crucial in ensuring the safety of electrical workers who may be exposed to potential arc flash hazards during their work.

While fire-retardant properties are important in protective clothing, they do not necessarily qualify the fabric for arc flash protection specifically. Similarly, being waterproof or having reflective materials may serve other safety functions but do not address the specific hazards associated with an arc flash. Thus, an arc-rated feature is paramount in ensuring safety against these particular risks.