NCED Electrical Systems & Wiring 2 — Questions and Answers
Question 1: What is the standard color code for the neutral wire in US residential wiring?
- White (Correct answer)
- Black
- Green
- Red
Correct answer: White
In US residential wiring, the neutral wire is white, the hot wire is black (or red), and the ground wire is green or bare copper.
Question 2: A GFCI outlet is required by the NEC in which of the following locations?
- Bathrooms (Correct answer)
- Bedroom closets
- Interior hallways
- Attic lighting circuits
Correct answer: Bathrooms
NEC requires GFCI protection in wet or damp locations including bathrooms, kitchens near sinks, garages, and outdoor areas.
Question 3: Which wire gauge is typically used for a 20-amp branch circuit in US residential wiring?
- 12 AWG (Correct answer)
- 14 AWG
- 10 AWG
- 8 AWG
Correct answer: 12 AWG
12 AWG copper wire is rated for 20 amps, while 14 AWG is used for 15-amp circuits.
Question 4: What does 'overcurrent protection' prevent in an electrical circuit?
- Excessive current that could cause overheating and fire (Correct answer)
- Voltage spikes from lightning strikes
- Power factor imbalance in three-phase systems
- Static buildup on ungrounded equipment
Correct answer: Excessive current that could cause overheating and fire
Overcurrent protection devices (fuses and breakers) interrupt the circuit when current exceeds safe levels, preventing overheating and fire.
Question 5: In a series circuit, if one component fails (open circuit), what happens to the other components?
- All components stop working (Correct answer)
- Remaining components continue to function
- Current increases through remaining components
- Voltage drops to zero across the failure point only
Correct answer: All components stop working
In a series circuit, current has only one path; an open in any component breaks the entire loop, stopping current flow everywhere.
Question 6: What is the purpose of a bonding conductor in an electrical system?
- To electrically connect metal parts so they share the same potential (Correct answer)
- To increase the voltage available to heavy appliances
- To reduce inductance in long wire runs
- To provide a return path for normal operating current
Correct answer: To electrically connect metal parts so they share the same potential
Bonding connects conductive metal parts together so they remain at the same voltage potential, reducing shock hazard if a fault occurs.
Question 7: Which type of conduit is non-metallic and often used in wet or corrosive environments?
- PVC (Schedule 40) (Correct answer)
- EMT (Electrical Metallic Tubing)
- IMC (Intermediate Metal Conduit)
- GRC (Galvanized Rigid Conduit)
Correct answer: PVC (Schedule 40)
PVC conduit is non-metallic, corrosion-resistant, and approved for wet locations, underground runs, and corrosive environments.
NCED Electrical Systems & Wiring 2
What is the standard color code for the neutral wire in US residential wiring?