CTE Electrical Systems & Wiring 2 โ Questions and Answers
Question 1: When teaching students about branch circuit protection, which device is specifically designed to protect against both overloads AND arc faults?
- Standard circuit breaker
- AFCI breaker (Correct answer)
- GFCI breaker
- Fuse link
Correct answer: AFCI breaker
Arc Fault Circuit Interrupters (AFCIs) detect dangerous arcing conditions that standard breakers miss, reducing fire risk from damaged wiring.
Question 2: A student measures 120V between the hot and neutral terminals but 0V between the hot and ground. What does this indicate?
- Normal wiring
- Open ground (Correct answer)
- Open neutral
- Reversed polarity
Correct answer: Open ground
An open ground means the ground wire is disconnected or missing, which is a shock hazard since the ground path is broken.
Question 3: In a CTE electrical lab, the NEC requires GFCI protection for all 125V, 15A and 20A receptacles in which location?
- Only outdoors
- Bathrooms only
- All areas within 6 feet of a sink (Correct answer)
- Any location with concrete floors
Correct answer: All areas within 6 feet of a sink
NEC 210.8 requires GFCI protection for receptacles within 6 feet of a sink regardless of room type.
Question 4: Which wiring method uses individual insulated conductors pulled through a metal or PVC conduit, offering the most protection and flexibility?
- Romex (NM cable)
- BX (AC cable)
- Conduit with THHN wire (Correct answer)
- MC cable
Correct answer: Conduit with THHN wire
THHN conductors in conduit allow individual wire replacement, offer mechanical protection, and can be rerouted by pulling new wires.
Question 5: A student is sizing a conductor for a 240V, 30A clothes dryer circuit. What is the minimum wire gauge required by NEC?
- 14 AWG
- 12 AWG
- 10 AWG (Correct answer)
- 8 AWG
Correct answer: 10 AWG
NEC requires 10 AWG copper conductors for 30A circuits, as 12 AWG is only rated for 20A.
Question 6: When demonstrating conduit bending to students, what is the maximum number of degrees of bends allowed between pull points in a conduit run?
- 180 degrees
- 270 degrees
- 360 degrees (Correct answer)
- 540 degrees
Correct answer: 360 degrees
NEC 358.26 limits conduit bends to 360 degrees total between pull boxes to prevent damage to conductors during wire pulling.
Question 7: In teaching Ohm's Law applications, if a circuit has 120V source and a 24-ohm resistive load, what is the current?
- 2A
- 5A (Correct answer)
- 10A
- 144A
Correct answer: 5A
Using I = V/R: 120V รท 24ฮฉ = 5A.
CTE Electrical Systems & Wiring 2
When teaching students about branch circuit protection, which device is specifically designed to protect against both overloads AND arc faults?