CEI Safety & Compliance Regulations 2 — Questions and Answers
Question 1: Under OSHA 29 CFR 1910.333, which condition requires electrical workers to use lockout/tagout procedures before working on energized equipment?
- When voltage exceeds 50V and unexpected energization could cause injury (Correct answer)
- Only when voltage exceeds 480V
- Whenever any electrical panel is open regardless of voltage
- Only in commercial occupancies with more than 20 circuits
Correct answer: When voltage exceeds 50V and unexpected energization could cause injury
OSHA 1910.333 requires LOTO when unexpected energization, startup, or release of stored energy could cause injury, specifically referencing equipment operating above 50 volts.
Question 2: Which NEC article specifically governs the installation of electrical systems in hazardous (classified) locations for Class I, Division 1 environments?
- Article 500 (Correct answer)
- Article 410
- Article 230
- Article 480
Correct answer: Article 500
NEC Article 500 covers electrical installations in hazardous classified locations including Class I (flammable gases/vapors), Class II (combustible dust), and Class III (ignitable fibers).
Question 3: A CEI inspector finds a commercial building with no arc flash hazard labels on switchgear. Which standard primarily requires these labels?
- NFPA 70E (Correct answer)
- NFPA 101
- IEEE 519
- ANSI Z535
Correct answer: NFPA 70E
NFPA 70E (Standard for Electrical Safety in the Workplace) requires arc flash hazard warning labels on electrical equipment to warn workers of potential arc flash energy.
Question 4: When inspecting a temporary power distribution system at a construction site, the NEC requires GFCI protection for all 120V, 15A and 20A receptacle outlets. Which NEC section covers this requirement?
- 590.6(A) (Correct answer)
- 406.4(D)
- 210.8(B)
- 300.5(D)
Correct answer: 590.6(A)
NEC 590.6(A) requires GFCI protection for all 120V, single-phase, 15A and 20A receptacle outlets on construction sites used for temporary power.
Question 5: Which of the following is the correct approach boundary distance for a 480V, three-phase system according to NFPA 70E?
- Restricted approach boundary is closer to the energized part than the limited approach boundary (Correct answer)
- Limited approach boundary is closer than the restricted approach boundary
- Both boundaries are equal at 480V
- Approach boundaries only apply above 600V
Correct answer: Restricted approach boundary is closer to the energized part than the limited approach boundary
NFPA 70E defines approach boundaries where restricted boundary (requiring PPE and training) is always closer to the energized conductor than the limited approach boundary.
Question 6: An electrical inspector observes that a contractor has installed EMT conduit in a concrete slab without using anti-short bushings where wires exit the conduit ends. Which NEC requirement is violated?
- Section 358.46 requires insulating bushings or equivalent protection at conduit ends where conductors might be abraded (Correct answer)
- Section 300.4 requires bushings only for rigid metal conduit, not EMT
- Section 230.54 requires weatherproof protection at all conduit entries
- Section 410.30 requires bushings only on luminaire feed conduits
Correct answer: Section 358.46 requires insulating bushings or equivalent protection at conduit ends where conductors might be abraded
NEC 358.46 requires that where EMT enters a box or fitting, a bushing or equivalent fitting must protect conductors from abrasion.
Question 7: During inspection of a hospital, an inspector finds that the essential electrical system was not separated into three branches as required. Which NFPA standard specifically mandates this branch separation?
- NFPA 99 (Correct answer)
- NFPA 70
- NFPA 101
- NFPA 110
Correct answer: NFPA 99
NFPA 99 (Health Care Facilities Code) requires the Essential Electrical System in hospitals to be divided into the Life Safety Branch, Critical Branch, and Equipment System.
CEI Safety & Compliance Regulations 2
Under OSHA 29 CFR 1910.333, which condition requires electrical workers to use lockout/tagout procedures before working on energized equipment?