CSLB C-10 Electrical ContractorSafety and TestingMedium
A qualified electrical worker is installing a new 277V lighting circuit. To comply with Cal/OSHA regulations for electrical installations, which of the following is a fundamental requirement regarding guarding of live parts?
- AOnly exposed live parts in public areas require guarding.
- BAll live parts must be guarded to prevent accidental contact by unqualified persons.
- CLive parts operating at 50V or less are not required to be guarded.
- DGuarding is only required for voltages exceeding 600V.
Show answer & explanationAnswer & explanation
Correct answer: B. All live parts must be guarded to prevent accidental contact by unqualified persons.
Cal/OSHA, consistent with NEC/CEC, requires all live parts of electrical equipment operating at 50 volts or more to be guarded against accidental contact by persons. The 277V circuit clearly falls into this category.
Why the other options are wrong
- A. Guarding is required in all locations where unqualified persons might come into contact, not just public areas, and also for qualified persons in certain scenarios.
- C. Cal/OSHA requires guarding for live parts operating at 50V or more, making this statement incorrect.
- D. Guarding is required for voltages much lower than 600V, specifically 50V and above.
Cal/OSHA Live Part Guarding
Requirement by Cal/OSHA to protect against accidental contact with energized electrical components operating at 50 volts or more.
- Applies to 50V and above
- Prevents accidental contact
- Achieved by enclosures, barriers, isolation, or elevation
Memory trick: Guard 50V and UP!