SEO Electrical Systems & Wiring 2 — Questions and Answers
Question 1: Which wire gauge is rated for 20-ampere branch circuits in residential wiring per NEC standards?
- 14 AWG
- 12 AWG (Correct answer)
- 10 AWG
- 8 AWG
Correct answer: 12 AWG
12 AWG copper wire is the minimum size required for 20-ampere branch circuits under NEC Article 310.
Question 2: What is the purpose of a GFCI outlet in a bathroom electrical circuit?
- Increase voltage output
- Protect against ground faults that can cause electrocution (Correct answer)
- Reduce power consumption
- Prevent circuit overloads
Correct answer: Protect against ground faults that can cause electrocution
A GFCI (Ground Fault Circuit Interrupter) detects imbalances in current flow and trips within milliseconds to prevent electrocution.
Question 3: In a standard 120V residential circuit, what color is typically used for the neutral wire?
- Black
- Red
- White or gray (Correct answer)
- Green
Correct answer: White or gray
NEC requires neutral conductors to be identified by white or gray insulation in standard residential wiring.
Question 4: What does the term 'ampacity' refer to in electrical wiring?
- The voltage drop across a conductor
- The maximum current a conductor can carry without exceeding its temperature rating (Correct answer)
- The total wattage a panel can supply
- The resistance of a wire per foot
Correct answer: The maximum current a conductor can carry without exceeding its temperature rating
Ampacity is the maximum current a conductor can continuously carry under specified conditions without damage.
Question 5: Which type of circuit breaker protects against both overloads and arc faults?
- Standard thermal-magnetic breaker
- GFCI breaker
- AFCI breaker (Correct answer)
- Double-pole breaker
Correct answer: AFCI breaker
An AFCI (Arc Fault Circuit Interrupter) breaker detects dangerous arc faults caused by damaged or loose wiring that standard breakers cannot sense.
Question 6: What is the correct method for connecting two conductors in a junction box?
- Tape them together with electrical tape only
- Twist them together and cover with a wire nut or approved connector (Correct answer)
- Solder the connection and leave exposed
- Use any available metal clip
Correct answer: Twist them together and cover with a wire nut or approved connector
NEC requires splices in junction boxes to be made with listed connectors such as wire nuts, and the box must remain accessible.
Question 7: How many conductors are typically found in a standard residential 120V branch circuit cable (Romex)?
- 1
- 2
- 3 (Correct answer)
- 4
Correct answer: 3
Standard NM cable (Romex) for 120V circuits contains 3 conductors: a hot (black), neutral (white), and bare ground wire.
SEO Electrical Systems & Wiring 2
Which wire gauge is rated for 20-ampere branch circuits in residential wiring per NEC standards?