Article 130 of NFPA 70E provides the requirements for work involving electrical hazards. All of Art. 130 (except Sec. 130.7) addresses such things as work practices and approach boundaries. Section 130.7, which comprises most of Art. 130 and includes several large tables, addresses PPE requirements.
Energized Work: What Are the PPE Requirements?
PPE is your last line of defense against electrical hazards; correct selection is critical.