IEC NEC Code General Requirements 3 — Questions and Answers
Question 1: According to NEC 110.26(B), what is the minimum width of the working space in front of electrical equipment?
- The width of the equipment or 24 inches, whichever is greater
- The width of the equipment or 30 inches, whichever is greater (Correct answer)
- 36 inches regardless of equipment width
- The width of the equipment or 36 inches, whichever is greater
Correct answer: The width of the equipment or 30 inches, whichever is greater
NEC 110.26(B) requires the working space width to be the width of the equipment or 30 inches, whichever is greater.
Question 2: Under NEC 110.16, electrical equipment in other than dwelling units must be marked to warn qualified persons of potential arc flash hazards. Where must this warning label be located?
- On the service entrance equipment only
- On the field wiring side of the equipment
- On the equipment so it is visible before examination, adjustment, servicing, or maintenance (Correct answer)
- Posted on the wall adjacent to the equipment
Correct answer: On the equipment so it is visible before examination, adjustment, servicing, or maintenance
NEC 110.16 requires arc flash warning labels to be field-applied to the equipment so the label is visible before examination, adjustment, servicing, or maintenance.
Question 3: What does NEC 110.2 state about the approval of conductors and equipment?
- All equipment must be approved by Underwriters Laboratories
- Conductors and equipment required or permitted by the NEC shall be acceptable only if approved (Correct answer)
- All equipment must carry a UL label to be installed
- Approval is required only for equipment rated over 600 volts
Correct answer: Conductors and equipment required or permitted by the NEC shall be acceptable only if approved
NEC 110.2 states that conductors and equipment required or permitted by the Code shall be acceptable only if approved by the authority having jurisdiction.
Question 4: NEC 110.26(C)(2) requires two entrances/exits from working spaces around electrical equipment under what condition?
- All equipment rated over 200 amperes
- Equipment rated 1200 amperes or more and over 6 feet wide (Correct answer)
- Any switchboard or panelboard over 400 amperes
- Equipment rated over 600 volts regardless of ampacity
Correct answer: Equipment rated 1200 amperes or more and over 6 feet wide
NEC 110.26(C)(2) requires two means of entrance/exit when the equipment is rated 1200 amperes or more and the working space is 6 feet wide or more.
Question 5: According to NEC 110.13, electrical equipment shall be firmly secured to the surface on which it is mounted. What exception exists for this requirement?
- Temporary wiring installations
- Plug-in type equipment (Correct answer)
- Equipment mounted on concrete walls
- Equipment rated under 15 amperes
Correct answer: Plug-in type equipment
NEC 110.13(A) requires firm securement, but plug-in type equipment that is designed to be connected by attachment plugs is exempted from this requirement.
Question 6: What is the NEC definition of 'Qualified Person' as it relates to electrical work under Article 100?
- A licensed master electrician in the jurisdiction
- One who has skills and knowledge related to the construction and operation of electrical equipment and installations and has received safety training (Correct answer)
- Any person who has completed an apprenticeship program
- A person certified by a nationally recognized testing laboratory
Correct answer: One who has skills and knowledge related to the construction and operation of electrical equipment and installations and has received safety training
NEC Article 100 defines a Qualified Person as one with the skills, knowledge, and safety training to work on electrical equipment and installations.
Question 7: Under NEC 110.26(E), where electrical equipment that could require examination, adjustment, or maintenance is installed above a suspended ceiling, what is required?
- A permanent ladder must be installed for access
- Access panels shall be provided and the working space requirements of 110.26(A) still apply above the ceiling (Correct answer)
- The equipment is exempt from working clearance requirements if behind an access panel
- Only equipment rated under 150 volts may be installed above suspended ceilings
Correct answer: Access panels shall be provided and the working space requirements of 110.26(A) still apply above the ceiling
NEC 110.26(E) requires that electrical equipment above suspended ceilings still meet working space requirements and have access panels provided.
IEC NEC Code General Requirements 3
According to NEC 110.26(B), what is the minimum width of the working space in front of electrical equipment?