Electrical Safety Practices Flashcards

Per OSHA 1910.333, what is the minimum approach distance for an unqualified person near exposed energized parts at 300 volts to ground?

Answer: 10 feet

OSHA 1910.333(c)(3) Table S-5 specifies that unqualified persons must maintain at least 10 feet from exposed energized parts operating at 300V to 750V.

What is the primary purpose of an energized electrical work permit per NFPA 70E?

Answer: To formally evaluate the hazard and justify why de-energizing is infeasible

An energized electrical work permit per NFPA 70E 130.2 documents the justification for not de-energizing and ensures proper safety measures are in place.

What does the term 'lockout/tagout' (LOTO) refer to in electrical safety?

Answer: Applying a physical lock and warning tag to energy-isolating devices to prevent re-energization

LOTO involves physically locking energy-isolating devices in the off position and attaching a warning tag to prevent accidental re-energization during maintenance.

Per NFPA 70E, what must be done to verify an electrically safe work condition after de-energizing equipment?

Answer: Test with a voltmeter to verify absence of voltage

NFPA 70E requires testing each conductor with an adequately rated voltage detector to verify absence of voltage before establishing an electrically safe work condition.

What class of fire extinguisher is required for electrical fires?

Answer: Class C

Class C fire extinguishers are rated for fires involving energized electrical equipment. The extinguishing agent is non-conductive.

What is the minimum arc flash PPE category for work on a 480V motor control center with the doors open per NFPA 70E Table 130.7(C)(15)(a)?

Answer: Category 2

NFPA 70E Table 130.7(C)(15)(a) typically assigns PPE Category 2 for working on 480V MCCs with doors open under normal conditions.