CSLB C10 EXAM 1-3 ACTUAL TEST 2026/2027 WITH
COMPLETE ACCURATE QUESTIONS AND CORRECT
DETAILED ANSWERS (CORRECT VERIFIED
SOLUTIONS) A NEW UPDATED VERSION
|GUARANTEED PASS A+
1. What is the primary purpose of reviewing electrical plans before beginning installation?
A. To determine the color of the electrician's tools
B. To identify system requirements, locations, and installation details
C. To eliminate the need for inspections
D. To determine the contractor's insurance premium
Answer: B
Rationale: Electrical plans communicate system layout, equipment locations, circuits, and
installation requirements. Reviewing them before work reduces errors and rework.
2. Which formula is used to calculate electrical power in a basic DC circuit?
A. P = V × I
B. P = V ÷ I
C. P = I ÷ R
D. P = R ÷ V
Answer: A
Rationale: Power in watts equals voltage multiplied by current: P = VI.
3. A 120-volt load draws 10 amperes. Approximately how much power does it consume?
A. 12 W
B. 120 W
C. 1,200 W
D. 12,000 W
Answer: C
Rationale: P = VI = 120 × 10 = 1,200 watts.
,4. What is the purpose of an electrical load calculation?
A. To select appropriate system and conductor capacities
B. To determine the paint color of equipment
C. To calculate employee wages
D. To identify the building owner
Answer: A
Rationale: Load calculations help determine the required capacity of feeders, services,
overcurrent protection, and related equipment.
5. Before selecting replacement electrical equipment, the contractor should primarily verify
the equipment's:
A. Manufacturer logo only
B. Electrical ratings and compatibility
C. Packaging color
D. Purchase location
Answer: B
Rationale: Replacement equipment must be electrically compatible and appropriately rated for
the system.
6. What does voltage represent in an electrical circuit?
A. Opposition to current
B. Electrical potential difference
C. Quantity of electrons only
D. Heat produced by a conductor
Answer: B
Rationale: Voltage is the electrical potential difference that drives current through a circuit.
7. What is the relationship described by Ohm's law?
, A. V = IR
B. V = I/R
C. R = V × I
D. I = V × R
Answer: A
Rationale: Ohm's law is V = IR, where V is voltage, I is current, and R is resistance.
8. A 24-ohm resistance connected to 120 V draws approximately:
A. 2 A
B. 5 A
C. 24 A
D. 2,880 A
Answer: B
Rationale: I = V/R = 120/24 = 5 A.
9. What should be considered when estimating electrical material quantities?
A. Only the number of workers
B. Plans, specifications, installation method, and material requirements
C. Only the building's age
D. Only the contractor's vehicle size
Answer: B
Rationale: Accurate estimating requires review of drawings, specifications, installation
conditions, and required materials.
10. Why is an existing electrical system evaluated before adding new equipment?
A. To determine whether the existing system can safely support the additional load
B. To avoid obtaining materials
C. To eliminate grounding
D. To eliminate circuit protection
Answer: A
COMPLETE ACCURATE QUESTIONS AND CORRECT
DETAILED ANSWERS (CORRECT VERIFIED
SOLUTIONS) A NEW UPDATED VERSION
|GUARANTEED PASS A+
1. What is the primary purpose of reviewing electrical plans before beginning installation?
A. To determine the color of the electrician's tools
B. To identify system requirements, locations, and installation details
C. To eliminate the need for inspections
D. To determine the contractor's insurance premium
Answer: B
Rationale: Electrical plans communicate system layout, equipment locations, circuits, and
installation requirements. Reviewing them before work reduces errors and rework.
2. Which formula is used to calculate electrical power in a basic DC circuit?
A. P = V × I
B. P = V ÷ I
C. P = I ÷ R
D. P = R ÷ V
Answer: A
Rationale: Power in watts equals voltage multiplied by current: P = VI.
3. A 120-volt load draws 10 amperes. Approximately how much power does it consume?
A. 12 W
B. 120 W
C. 1,200 W
D. 12,000 W
Answer: C
Rationale: P = VI = 120 × 10 = 1,200 watts.
,4. What is the purpose of an electrical load calculation?
A. To select appropriate system and conductor capacities
B. To determine the paint color of equipment
C. To calculate employee wages
D. To identify the building owner
Answer: A
Rationale: Load calculations help determine the required capacity of feeders, services,
overcurrent protection, and related equipment.
5. Before selecting replacement electrical equipment, the contractor should primarily verify
the equipment's:
A. Manufacturer logo only
B. Electrical ratings and compatibility
C. Packaging color
D. Purchase location
Answer: B
Rationale: Replacement equipment must be electrically compatible and appropriately rated for
the system.
6. What does voltage represent in an electrical circuit?
A. Opposition to current
B. Electrical potential difference
C. Quantity of electrons only
D. Heat produced by a conductor
Answer: B
Rationale: Voltage is the electrical potential difference that drives current through a circuit.
7. What is the relationship described by Ohm's law?
, A. V = IR
B. V = I/R
C. R = V × I
D. I = V × R
Answer: A
Rationale: Ohm's law is V = IR, where V is voltage, I is current, and R is resistance.
8. A 24-ohm resistance connected to 120 V draws approximately:
A. 2 A
B. 5 A
C. 24 A
D. 2,880 A
Answer: B
Rationale: I = V/R = 120/24 = 5 A.
9. What should be considered when estimating electrical material quantities?
A. Only the number of workers
B. Plans, specifications, installation method, and material requirements
C. Only the building's age
D. Only the contractor's vehicle size
Answer: B
Rationale: Accurate estimating requires review of drawings, specifications, installation
conditions, and required materials.
10. Why is an existing electrical system evaluated before adding new equipment?
A. To determine whether the existing system can safely support the additional load
B. To avoid obtaining materials
C. To eliminate grounding
D. To eliminate circuit protection
Answer: A
