Texas Electrical Contractor Licensing
Examination — Unlimited Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which type of wiring method is most commonly used in residential
construction?
A. Rigid metal conduit
B. Nonmetallic sheathed cable (NM)
C. Armored cable
D. Surface metal raceway
Rationale: NM cable is widely used in residential settings due to ease
of installation and cost efficiency.
2. What is the minimum size grounding conductor for a 100-ampere
service using copper conductors?
, A. 8 AWG
B. 6 AWG
C. 4 AWG
D. 3 AWG
Rationale: NEC Table 250.66 specifies 3 AWG copper for a 100-amp
service.
3. Which device is used to protect against overcurrent in a circuit?
A. Contactor
B. Transformer
C. Circuit breaker
D. Surge suppressor
Rationale: Circuit breakers interrupt current flow when an
overcurrent condition occurs.
4. For a 240V single-phase load, what is the correct calculation for
current if the load is 12 kW?
A. 50 A
B. 50 A
C. 60 A
D. 48 A
Rationale: Current I = P/V = 12,000 W / 240 V = 50 A.
5. Which NEC article covers grounding and bonding?
A. Article 300
B. Article 250
, C. Article 210
D. Article 408
Rationale: NEC Article 250 provides the requirements for grounding
and bonding.
6. What is the maximum distance allowed for a 15-ampere, 120V branch
circuit to a general-use receptacle?
A. 25 ft
B. 30 ft
C. 50 ft
D. 100 ft
Rationale: NEC Section 210.52 allows 50 ft spacing for general-use
receptacles.
7. Which conductor material has the highest conductivity?
A. Aluminum
B. Copper
C. Silver
D. Brass
Rationale: Silver has the highest electrical conductivity of all common
metals.
8. What is the maximum number of 90°C rated conductors in a 4-inch
EMT raceway?
A. 8
B. 10
, C. 12
D. 14
Rationale: NEC Chapter 9, Table 1, and Annex C provide fill
capacities; 10 is the maximum for 90°C conductors.
9. A 3-phase, 480V delta system has a load of 60 kVA. What is the line
current?
A. 50 A
B. 60 A
C. 72.2 A
D. 80 A
Rationale: I_line = S / (√3 × V) = 60,000 / (1.732 × 480) ≈ 72.2 A.
10. Which type of motor requires a capacitor for starting?
A. Synchronous
B. Single-phase induction
C. Three-phase induction
D. DC shunt
Rationale: Single-phase induction motors use a start capacitor to
create a phase shift for starting torque.
11. Which insulation type is rated for 600V and is commonly used in
industrial cable?
A. THWN
B. THHN
C. UF
Examination — Unlimited Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which type of wiring method is most commonly used in residential
construction?
A. Rigid metal conduit
B. Nonmetallic sheathed cable (NM)
C. Armored cable
D. Surface metal raceway
Rationale: NM cable is widely used in residential settings due to ease
of installation and cost efficiency.
2. What is the minimum size grounding conductor for a 100-ampere
service using copper conductors?
, A. 8 AWG
B. 6 AWG
C. 4 AWG
D. 3 AWG
Rationale: NEC Table 250.66 specifies 3 AWG copper for a 100-amp
service.
3. Which device is used to protect against overcurrent in a circuit?
A. Contactor
B. Transformer
C. Circuit breaker
D. Surge suppressor
Rationale: Circuit breakers interrupt current flow when an
overcurrent condition occurs.
4. For a 240V single-phase load, what is the correct calculation for
current if the load is 12 kW?
A. 50 A
B. 50 A
C. 60 A
D. 48 A
Rationale: Current I = P/V = 12,000 W / 240 V = 50 A.
5. Which NEC article covers grounding and bonding?
A. Article 300
B. Article 250
, C. Article 210
D. Article 408
Rationale: NEC Article 250 provides the requirements for grounding
and bonding.
6. What is the maximum distance allowed for a 15-ampere, 120V branch
circuit to a general-use receptacle?
A. 25 ft
B. 30 ft
C. 50 ft
D. 100 ft
Rationale: NEC Section 210.52 allows 50 ft spacing for general-use
receptacles.
7. Which conductor material has the highest conductivity?
A. Aluminum
B. Copper
C. Silver
D. Brass
Rationale: Silver has the highest electrical conductivity of all common
metals.
8. What is the maximum number of 90°C rated conductors in a 4-inch
EMT raceway?
A. 8
B. 10
, C. 12
D. 14
Rationale: NEC Chapter 9, Table 1, and Annex C provide fill
capacities; 10 is the maximum for 90°C conductors.
9. A 3-phase, 480V delta system has a load of 60 kVA. What is the line
current?
A. 50 A
B. 60 A
C. 72.2 A
D. 80 A
Rationale: I_line = S / (√3 × V) = 60,000 / (1.732 × 480) ≈ 72.2 A.
10. Which type of motor requires a capacitor for starting?
A. Synchronous
B. Single-phase induction
C. Three-phase induction
D. DC shunt
Rationale: Single-phase induction motors use a start capacitor to
create a phase shift for starting torque.
11. Which insulation type is rated for 600V and is commonly used in
industrial cable?
A. THWN
B. THHN
C. UF
