NEC Safety Procedures & Code Compliance 2 — Questions and Answers
Question 1: What is the minimum working clearance depth in front of electrical equipment rated 0-150V to ground operating at 600V or less, Condition 1?
- 3 feet (Correct answer)
- 3.5 feet
- 4 feet
- 2 feet
Correct answer: 3 feet
NEC Table 110.26(A)(1) requires 3 feet of clear working space for Condition 1 at 0-150V.
Question 2: Per NEC 110.26, what is the minimum headroom of working spaces about service equipment, switchboards, and panelboards?
- 5 feet
- 6 feet
- 6.5 feet (Correct answer)
- 7 feet
Correct answer: 6.5 feet
NEC 110.26(E) requires minimum 6.5 ft headroom or the height of the equipment, whichever is greater.
Question 3: What does a Ground-Fault Circuit Interrupter (GFCI) primarily protect against?
- Overcurrent
- Electric shock to people (Correct answer)
- Short circuits
- Voltage surges
Correct answer: Electric shock to people
GFCIs protect people by quickly opening the circuit when ground-fault current is detected.
Question 4: At what level of ground-fault current does a Class A GFCI trip?
- 2 milliamps
- 4-6 milliamps (Correct answer)
- 15 milliamps
- 30 milliamps
Correct answer: 4-6 milliamps
A Class A GFCI trips at 4-6 mA of ground-fault current.
Question 5: Which color is required for the grounded (neutral) conductor of sizes 6 AWG or smaller per NEC 200.6?
- Green
- White or gray (Correct answer)
- Black
- Red
Correct answer: White or gray
NEC 200.6 requires grounded conductors 6 AWG and smaller to be white or gray.
Question 6: What is the maximum allowable voltage drop recommended by NEC for branch circuits (informational note)?
- 1%
- 3% (Correct answer)
- 5%
- 8%
Correct answer: 3%
NEC recommends a maximum 3% voltage drop on branch circuits (5% combined feeder and branch).
Question 7: Before working on a circuit, which procedure verifies de-energization in lockout/tagout?
- Visual inspection only
- Test for absence of voltage with a meter (Correct answer)
- Asking a coworker
- Checking the panel label
Correct answer: Test for absence of voltage with a meter
Safe procedure requires testing for the absence of voltage with a properly rated meter.
NEC Safety Procedures & Code Compliance 2
What is the minimum working clearance depth in front of electrical equipment rated 0-150V to ground operating at 600V or less, Condition 1?