IEC NEC Code General Requirements 2 — Questions and Answers
Question 1: According to NEC Article 110, what is the minimum working space depth required in front of electrical equipment rated 0-150 volts to ground where there are exposed live parts on one side and no live or grounded parts on the other?
- 2 feet
- 3 feet (Correct answer)
- 4 feet
- 6 feet
Correct answer: 3 feet
NEC 110.26(A)(1) Condition 1 requires a minimum working space depth of 3 feet for equipment rated 0-150 volts to ground.
Question 2: Under NEC 110.12, electrical equipment must be installed in a neat and workmanlike manner. Which of the following would be a violation of this requirement?
- Using conduit straps every 10 feet on a horizontal run
- Leaving excess wire bundled loosely inside a panel (Correct answer)
- Securing cables at required intervals per their article
- Using listed fittings at all enclosure entries
Correct answer: Leaving excess wire bundled loosely inside a panel
NEC 110.12 requires workmanlike installation; bundled excess wire stuffed loosely in a panel is not considered neat or professional.
Question 3: What does NEC 110.3(B) require regarding the installation of listed or labeled equipment?
- Equipment must be installed only by licensed electricians
- Equipment must be installed and used in accordance with any instructions included in the listing or labeling (Correct answer)
- Equipment listing must be verified by the authority having jurisdiction before installation
- Listed equipment may substitute for any NEC requirement
Correct answer: Equipment must be installed and used in accordance with any instructions included in the listing or labeling
NEC 110.3(B) states that listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.
Question 4: NEC 110.26(A)(3) specifies the minimum headroom for working spaces about electrical equipment. What is the minimum headroom required?
- 5 feet 6 inches
- 6 feet (Correct answer)
- 6 feet 6 inches
- 7 feet
Correct answer: 6 feet
NEC 110.26(A)(3) requires a minimum headroom of 6 feet, or the height of the equipment, whichever is greater.
Question 5: According to NEC 110.14, when conductors of different metals are connected in a device, what must the device be suitable for?
- The higher ampacity conductor only
- Use with each metal connected (Correct answer)
- Copper conductors only unless otherwise marked
- Aluminum conductors only in outdoor locations
Correct answer: Use with each metal connected
NEC 110.14 requires that connectors and terminals for conductors of different metals be identified for use with each metal to prevent galvanic corrosion.
Question 6: What is the purpose of the 'interrupting rating' requirement found in NEC 110.9?
- To ensure equipment can handle continuous load currents
- To ensure protective devices can safely interrupt the maximum available fault current (Correct answer)
- To limit the maximum ampere rating of overcurrent devices
- To specify the voltage rating of circuit breakers
Correct answer: To ensure protective devices can safely interrupt the maximum available fault current
NEC 110.9 requires that overcurrent protective devices have an interrupting rating sufficient for the nominal circuit voltage and current that is available at the line terminals.
Question 7: NEC 110.22 requires that each disconnecting means be legibly marked. Which of the following is NOT required by this section?
- The purpose of the disconnecting means
- The manufacturer's name on the disconnect (Correct answer)
- Warning labels on series-rated equipment
- Clear identification on circuit directory for panelboards
Correct answer: The manufacturer's name on the disconnect
NEC 110.22 requires identification of purpose but does not require the manufacturer's name to be marked on the disconnecting means.
IEC NEC Code General Requirements 2
According to NEC Article 110, what is the minimum working space depth required in front of electrical equipment rated 0-150 volts to ground where there are exposed live parts on one side and no live or grounded parts on the other?