Special relays have now been developed by companies to specifically reduce the risks from an arc flash.
These units are designed to operate extremely quickly in the event of a fault. They work by detecting the side effect of an arc flash, the most popular is detecting an increase in light. Some units also can combine this with a current module to prevent false trips due to a light sensor picking up a torch or camera flash.
These systems have the potential to reduce the total tripping time down to under 100mS and consequently reduce the arc energy to under 4 cal/cm² or NFPA class 1.