California Electrical Contractor (C-10) License
Exam | COMPREHENSIVE EXAM WITH
CORRECT VERIFIED ANSWERS AND
RATIONALES. ALREADY GRADED A+
1. The primary purpose of the National Electrical Code
(NEC) is to:
A. Ensure electrical installations are energy efficient
B. Provide safety standards for electrical installations ✅
C. Regulate electrical labor wages
D. Standardize electrical equipment prices
Rationale: NEC sets minimum safety standards to protect
people and property.
2. Electrical contractors must obtain permits before:
A. Installing or altering electrical systems ✅
B. Cleaning circuit breakers
C. Ordering materials
D. Training electricians
Rationale: Permits ensure work complies with state and
local codes.
3. Grounding an electrical system is important because it:
,A. Reduces energy consumption
B. Protects against electrical shock ✅
C. Increases voltage
D. Eliminates maintenance
Rationale: Grounding safely directs fault currents to the
earth.
4. The minimum wire size for a 20-amp residential circuit is:
A. 14 AWG ✅
B. 12 AWG
C. 10 AWG
D. 8 AWG
Rationale: NEC specifies 14 AWG for 15–20 amps to prevent
overheating.
5. Electrical contractors must provide which type of
insurance for employees?
A. Health insurance only
B. Life insurance only
C. Workers’ compensation ✅
D. Liability insurance only
Rationale: Workers’ compensation protects employees from
workplace injuries.
,6. The maximum number of outlets on a 15-amp, 120V
branch circuit is:
A. 10 ✅
B. 12
C. 15
D. 20
Rationale: NEC recommends 10 outlets to prevent overload.
7. A GFCI (Ground Fault Circuit Interrupter) protects:
A. Appliances only
B. People from electrical shock ✅
C. Wiring from overheating
D. Only motors
Rationale: GFCI detects ground faults and interrupts the
circuit to prevent shocks.
8. Conduit fill calculations are required to:
A. Determine wire lengths
B. Ensure wires are not overcrowded ✅
C. Calculate voltage drop
D. Estimate installation time
, Rationale: Proper fill prevents overheating and allows
maintenance.
9. Electrical contractors must maintain which records for
audits?
A. Contracts, payments, and inspection logs ✅
B. Marketing materials
C. Employee resumes
D. Equipment brochures
Rationale: Documentation ensures accountability and
regulatory compliance.
10. Electrical service panels must have:
A. Proper labeling of circuits ✅
B. Color-coded wires only
C. Only one main breaker
D. Multiple unprotected circuits
Rationale: Labeling ensures safe identification and
maintenance.
Exam | COMPREHENSIVE EXAM WITH
CORRECT VERIFIED ANSWERS AND
RATIONALES. ALREADY GRADED A+
1. The primary purpose of the National Electrical Code
(NEC) is to:
A. Ensure electrical installations are energy efficient
B. Provide safety standards for electrical installations ✅
C. Regulate electrical labor wages
D. Standardize electrical equipment prices
Rationale: NEC sets minimum safety standards to protect
people and property.
2. Electrical contractors must obtain permits before:
A. Installing or altering electrical systems ✅
B. Cleaning circuit breakers
C. Ordering materials
D. Training electricians
Rationale: Permits ensure work complies with state and
local codes.
3. Grounding an electrical system is important because it:
,A. Reduces energy consumption
B. Protects against electrical shock ✅
C. Increases voltage
D. Eliminates maintenance
Rationale: Grounding safely directs fault currents to the
earth.
4. The minimum wire size for a 20-amp residential circuit is:
A. 14 AWG ✅
B. 12 AWG
C. 10 AWG
D. 8 AWG
Rationale: NEC specifies 14 AWG for 15–20 amps to prevent
overheating.
5. Electrical contractors must provide which type of
insurance for employees?
A. Health insurance only
B. Life insurance only
C. Workers’ compensation ✅
D. Liability insurance only
Rationale: Workers’ compensation protects employees from
workplace injuries.
,6. The maximum number of outlets on a 15-amp, 120V
branch circuit is:
A. 10 ✅
B. 12
C. 15
D. 20
Rationale: NEC recommends 10 outlets to prevent overload.
7. A GFCI (Ground Fault Circuit Interrupter) protects:
A. Appliances only
B. People from electrical shock ✅
C. Wiring from overheating
D. Only motors
Rationale: GFCI detects ground faults and interrupts the
circuit to prevent shocks.
8. Conduit fill calculations are required to:
A. Determine wire lengths
B. Ensure wires are not overcrowded ✅
C. Calculate voltage drop
D. Estimate installation time
, Rationale: Proper fill prevents overheating and allows
maintenance.
9. Electrical contractors must maintain which records for
audits?
A. Contracts, payments, and inspection logs ✅
B. Marketing materials
C. Employee resumes
D. Equipment brochures
Rationale: Documentation ensures accountability and
regulatory compliance.
10. Electrical service panels must have:
A. Proper labeling of circuits ✅
B. Color-coded wires only
C. Only one main breaker
D. Multiple unprotected circuits
Rationale: Labeling ensures safe identification and
maintenance.
