Personal Protective Equipment (PPE) provides protection after an arc flash incident has occurred and should be viewed as the last line of protection. Arc flash rated clothing / PPE is required when the worker may be exposed to this risk when equipment is open for maintenance (energized or when establishing an Electrically Safe Work Condition), or even when a risk assessment has determined that switching or operation of closed equipment poses risk to the worker. The arc rated clothing requirements for various electrical equipment shall be determined by an arc flash risk assessment as stated in the NFPA 70E.