ULTIMATE CALIFORNIA C-10 ELECTRICAL
LICENSE TEST BANK [UPDATED ACTUAL
QUESTIONS]
Unlock your pathway to passing the California electrical licensing
exam with this comprehensive master practice test bank. Expertly
curated to match the official CSLB blueprint, this guide features
real exam-style questions covering the National Electrical Code
(NEC), California Electrical Code (CEC), and state business law.
Every question is paired with precise, italicised answers and bold
italicised rationales to ensure deep conceptual understanding and
rapid study retention.
1. According to NEC Section 110.26(A)(1), what
is the minimum clear working space depth
required in front of a 120/208V panelboard where
there are grounded parts or concrete walls on
the opposite side of the working space
(Condition 2)?
A) 30 inches
B) 36 inches
C) 42 inches
D) 48 inches
Rationale: NEC Section 110.26(A)(1) and Table
110.26(A)(1) specify that for systems operating at
0 to 150 volts to ground, the minimum clear
working depth for Condition 2 (grounded
surfaces opposite the live parts) is 3 feet (36
,inches). 30 inches is the minimum required
width, not depth.
2. Per NEC Table 300.5, what is the minimum
burial depth for a Type UF direct-burial cable
supplying a residential 120V branch circuit under
a residential lawn or flower bed not subject to
vehicular traffic?
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Rationale: NEC Table 300.5 Column 1 dictates
that direct-burial cables (like Type UF) buried
under general areas not subject to commercial
vehicular traffic must have a minimum earth
cover of 24 inches. Column 4 allows 12 inches
only if the circuit is GFCI-protected and rated
20A or less.
3. According to NEC Section 210.52(A)(1), what
is the maximum horizontal distance that any
point along the floor line in a habitable room wall
space can be from a receptacle outlet?
A) 4 feet
B) 6 feet
,C) 8 feet
D) 12 feet
Rationale: NEC Section 210.52(A)(1) states that
receptacles must be installed such that no point
measured horizontally along the floor line in any
wall space is more than 6 feet from an outlet.
This establishes the standard 12-foot maximum
spacing rule between receptacles in residential
rooms.
4. When two or more ground rods are driven to
form a grounding electrode system per NEC
Section 250.53(A)(3), what is the minimum
required distance they must be spaced apart?
A) 4 feet
B) 6 feet
C) 8 feet
D) 10 feet
Rationale: NEC Section 250.53(A)(3) requires that
rod, pipe, or plate electrodes be spaced at least 6
feet apart. Spacing them closer than 6 feet
reduces their cumulative efficiency because their
earth-resistance shells overlap.
5. A branch circuit supplies a continuous
commercial load of 48 Amperes. What is the
, minimum overcurrent protection device (OCPD)
size required for this circuit?
A) 50 Amperes
B) 60 Amperes
C) 70 Amperes
D) 80 Amperes
Rationale: NEC Section 210.20(A) requires the
overcurrent protection device for continuous
loads to be sized at no less than 125% of the
continuous load. Calculating 48A × 1.25 = 60
Amperes. Therefore, a 60A breaker is the
minimum required.
6. According to NEC Table 310.15(C)(1), what
adjustment factor (derating) must be applied to
the allowable ampacity of conductors when 4 to
6 current-carrying conductors are installed in a
single raceway?
A) 90%
B) 80%
C) 70%
D) 50%
Rationale: NEC Table 310.15(C)(1) outlines
ampacity adjustment factors for bundles of
current-carrying conductors. For 4 to 6 current-
carrying conductors in a single raceway or
LICENSE TEST BANK [UPDATED ACTUAL
QUESTIONS]
Unlock your pathway to passing the California electrical licensing
exam with this comprehensive master practice test bank. Expertly
curated to match the official CSLB blueprint, this guide features
real exam-style questions covering the National Electrical Code
(NEC), California Electrical Code (CEC), and state business law.
Every question is paired with precise, italicised answers and bold
italicised rationales to ensure deep conceptual understanding and
rapid study retention.
1. According to NEC Section 110.26(A)(1), what
is the minimum clear working space depth
required in front of a 120/208V panelboard where
there are grounded parts or concrete walls on
the opposite side of the working space
(Condition 2)?
A) 30 inches
B) 36 inches
C) 42 inches
D) 48 inches
Rationale: NEC Section 110.26(A)(1) and Table
110.26(A)(1) specify that for systems operating at
0 to 150 volts to ground, the minimum clear
working depth for Condition 2 (grounded
surfaces opposite the live parts) is 3 feet (36
,inches). 30 inches is the minimum required
width, not depth.
2. Per NEC Table 300.5, what is the minimum
burial depth for a Type UF direct-burial cable
supplying a residential 120V branch circuit under
a residential lawn or flower bed not subject to
vehicular traffic?
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Rationale: NEC Table 300.5 Column 1 dictates
that direct-burial cables (like Type UF) buried
under general areas not subject to commercial
vehicular traffic must have a minimum earth
cover of 24 inches. Column 4 allows 12 inches
only if the circuit is GFCI-protected and rated
20A or less.
3. According to NEC Section 210.52(A)(1), what
is the maximum horizontal distance that any
point along the floor line in a habitable room wall
space can be from a receptacle outlet?
A) 4 feet
B) 6 feet
,C) 8 feet
D) 12 feet
Rationale: NEC Section 210.52(A)(1) states that
receptacles must be installed such that no point
measured horizontally along the floor line in any
wall space is more than 6 feet from an outlet.
This establishes the standard 12-foot maximum
spacing rule between receptacles in residential
rooms.
4. When two or more ground rods are driven to
form a grounding electrode system per NEC
Section 250.53(A)(3), what is the minimum
required distance they must be spaced apart?
A) 4 feet
B) 6 feet
C) 8 feet
D) 10 feet
Rationale: NEC Section 250.53(A)(3) requires that
rod, pipe, or plate electrodes be spaced at least 6
feet apart. Spacing them closer than 6 feet
reduces their cumulative efficiency because their
earth-resistance shells overlap.
5. A branch circuit supplies a continuous
commercial load of 48 Amperes. What is the
, minimum overcurrent protection device (OCPD)
size required for this circuit?
A) 50 Amperes
B) 60 Amperes
C) 70 Amperes
D) 80 Amperes
Rationale: NEC Section 210.20(A) requires the
overcurrent protection device for continuous
loads to be sized at no less than 125% of the
continuous load. Calculating 48A × 1.25 = 60
Amperes. Therefore, a 60A breaker is the
minimum required.
6. According to NEC Table 310.15(C)(1), what
adjustment factor (derating) must be applied to
the allowable ampacity of conductors when 4 to
6 current-carrying conductors are installed in a
single raceway?
A) 90%
B) 80%
C) 70%
D) 50%
Rationale: NEC Table 310.15(C)(1) outlines
ampacity adjustment factors for bundles of
current-carrying conductors. For 4 to 6 current-
carrying conductors in a single raceway or
