The best protection against arc blast is "don’t be there." This, however, isn't always possible. The next best precaution is to minimize your exposure (do as much as possible outside the hazardous area) and wear the proper PPE.
You may need to wear protective sleeves, a blast suit, or other protective clothing. Don't fall into the trap of asking, "What can I get by with?" Instead, ask what you must do to protect yourself against the highest energy hazard available in this location.
Thoroughly assess the situation before making PPE decisions.
Avoid "calculation obsession." Protection calculations determine the minimum protection. You aren't required to downgrade protection to fit those calculations.
Remember that there is always enough time to perform the proper safety analysis prior to commencing work. You may not get a second chance.