CALFORNIA C10 ELECTRICAL COMPREHENISVE EXAMS
2025/2026 QUESTIONS WITH ANSWERS RATED A+
✔✔On a 240-volt, single-phase, 3-wire system, the neutral conductor will _____.
A-never carry current even when the other conductors carry a different amount
B-never carry current larger than the difference between the current in the two
ungrounded (hot) conductors
C-carry current equal to the current between phases
D-carry current equal to one-half the current between phases - ✔✔The Correct Answer
Is B
On a 240-volt, single-phase, 3-wire system, the neutral conductor will never carry
current larger than the difference between the current in the two ungrounded (hot)
conductors.
✔✔The minimum allowable current rating of 3-wire service-entrance conductors for a
one-family dwelling is _____.
A-60 amperes
B-100 amperes
C-125 amperes
D-150 amperes - ✔✔The Correct Answer Is B
NEC Section 230.42 states that the ungrounded conductors for specific installations not
be smaller than the disconnecting means. NEC 230.79(C) requires the service
disconnecting means for a one-family dwelling not be less than 100 amperes.
✔✔The minimum allowable current rating of 3-wire service-entrance conductors for a
one-family dwelling with an initial net computed load of 10 kVA or more is _____.
A-60 amperes
B-100 amperes
C-125 amperes
D-150 amperes - ✔✔The Correct Answer Is B
Regardless of the computed load or the number of circuits, a one-family dwelling shall
have a minimum service size of 100 amperes.
✔✔What is the smallest copper wire size allowed for service-entrance conductors?
A-No. 10 AWG
B-No. 8 AWG
C-No. 12 AWG
D-No. 4 AWG - ✔✔The Correct Answer Is B
Service-entrance conductors shall not be smaller than No. 8 copper or No. 6 aluminum.
✔✔The smallest grounded or neutral conductor for an electric service using 1100 kcmil
copper conductors is _____.
A-2/0 copper
B-3/0 copper
C-1/0 copper
,D-1/0 copper - ✔✔The Correct Answer Is A
For service-entrance conductors, the grounded conductor shall not be smaller than
indicated in NEC Table 250-66. NEC Section 250.24(B)(1)
✔✔What is the smallest aluminum or copper-clad wire size allowed for service-entrance
conductors?
A-No. 10 AWG
B-No. 12 AWG
C-No. 6 AWG
D-No. 4 AWG - ✔✔The Correct Answer Is C
The smallest size wire that can be used as service-entrance conductor is No. 8 copper
or No. 6 aluminum NEC 230.31(B)
✔✔The name given to a system or circuit conductor that is intentionally grounded is
_____.
A-grounding conductor
B-bonding conductor
C-high-leg conductor
D-grounding or neutral conductor - ✔✔The Correct Answer Is D
An intentionally grounded conductor is a grounded conductor as explained in NEC
Article 100, Definitions.
✔✔What is the smallest copper wire size allowed for service-entrance conductors
supplying loads consisting of limited loads of a single branch circuit?
A-No. 10 AWG
B-No. 12 AWG
C-No. 4 AWG
D-No. 6 AWG - ✔✔The Correct Answer Is B
For limited loads of a single branch circuit, No. 12 copper may be used, but in no case
can they be smaller than the branch-circuit conductors.
✔✔The allowable number of service disconnects can consist of up to _____ circuit
breakers.
A-three
B-four
C-five
D-six - ✔✔The Correct Answer Is D
The service disconnection means shall consist of not more than six circuit breakers.
NEC Section 230.71(A).
✔✔Multiconductor cables used for service drops must be attached to buildings or other
structures by _____.
A-tie wires
B-fittings approved for the purpose
C-16d nails or larger
, D-tapcons - ✔✔The Correct Answer Is B
An approved fitting, such as an insulator, is required for all such installations.
✔✔Service heads for overhead service-entrance conductors must be _____.
A-explosion-proof
B-raintight
C-waterproof
D-dust-proof - ✔✔The Correct Answer Is B
Service heads must be constructed and protected to prevent rain from interfering with
the successful operation of the service-entrance conductors. NEC Section 230.54(A).
✔✔Service-entrance cable must be supported within what distance from the service
head?
A-12 inches
B-18 inches
C-24 inches
D-36 inches - ✔✔The Correct Answer Is A
An SE cable strap or other approved fitting must be installed within 12 inches of the
service head.
✔✔Service-entrance cable must also be supported at intervals of _____.
A-2 feet
B-2-1/2 feet
C-3 feet
D-4-1/2 feet - ✔✔The Correct Answer Is B
Type SE cable must be supported at least every 2-1/2 feet (30 inches) to prevent sag or
collapse of the cable.
✔✔What clearance must service conductors have from windows, doors, porches, fire
escapes, or similar locations?
A-1 foot
B-2 feet
C-3 feet
D-4 feet - ✔✔The Correct Answer Is C
Service conductors installed as open conductors or multi-conductor cable without an
overall outer jacket shall have a clearance of not less than 3 feet from windows, doors,
porches, fire escapes, or similar locations. Conductors run above the top level of a
window, however, shall be permitted to be less than 3 feet. NEC Section 230.9
✔✔When installing a service head, the conductors of different potential should be
_____.
A-brought out through seperately bushed openings
B-brought out through the same bushed openings
C-brought out through the same unbushed openings
D-brought out through separately unbushed openings - ✔✔The Correct Answer Is A
2025/2026 QUESTIONS WITH ANSWERS RATED A+
✔✔On a 240-volt, single-phase, 3-wire system, the neutral conductor will _____.
A-never carry current even when the other conductors carry a different amount
B-never carry current larger than the difference between the current in the two
ungrounded (hot) conductors
C-carry current equal to the current between phases
D-carry current equal to one-half the current between phases - ✔✔The Correct Answer
Is B
On a 240-volt, single-phase, 3-wire system, the neutral conductor will never carry
current larger than the difference between the current in the two ungrounded (hot)
conductors.
✔✔The minimum allowable current rating of 3-wire service-entrance conductors for a
one-family dwelling is _____.
A-60 amperes
B-100 amperes
C-125 amperes
D-150 amperes - ✔✔The Correct Answer Is B
NEC Section 230.42 states that the ungrounded conductors for specific installations not
be smaller than the disconnecting means. NEC 230.79(C) requires the service
disconnecting means for a one-family dwelling not be less than 100 amperes.
✔✔The minimum allowable current rating of 3-wire service-entrance conductors for a
one-family dwelling with an initial net computed load of 10 kVA or more is _____.
A-60 amperes
B-100 amperes
C-125 amperes
D-150 amperes - ✔✔The Correct Answer Is B
Regardless of the computed load or the number of circuits, a one-family dwelling shall
have a minimum service size of 100 amperes.
✔✔What is the smallest copper wire size allowed for service-entrance conductors?
A-No. 10 AWG
B-No. 8 AWG
C-No. 12 AWG
D-No. 4 AWG - ✔✔The Correct Answer Is B
Service-entrance conductors shall not be smaller than No. 8 copper or No. 6 aluminum.
✔✔The smallest grounded or neutral conductor for an electric service using 1100 kcmil
copper conductors is _____.
A-2/0 copper
B-3/0 copper
C-1/0 copper
,D-1/0 copper - ✔✔The Correct Answer Is A
For service-entrance conductors, the grounded conductor shall not be smaller than
indicated in NEC Table 250-66. NEC Section 250.24(B)(1)
✔✔What is the smallest aluminum or copper-clad wire size allowed for service-entrance
conductors?
A-No. 10 AWG
B-No. 12 AWG
C-No. 6 AWG
D-No. 4 AWG - ✔✔The Correct Answer Is C
The smallest size wire that can be used as service-entrance conductor is No. 8 copper
or No. 6 aluminum NEC 230.31(B)
✔✔The name given to a system or circuit conductor that is intentionally grounded is
_____.
A-grounding conductor
B-bonding conductor
C-high-leg conductor
D-grounding or neutral conductor - ✔✔The Correct Answer Is D
An intentionally grounded conductor is a grounded conductor as explained in NEC
Article 100, Definitions.
✔✔What is the smallest copper wire size allowed for service-entrance conductors
supplying loads consisting of limited loads of a single branch circuit?
A-No. 10 AWG
B-No. 12 AWG
C-No. 4 AWG
D-No. 6 AWG - ✔✔The Correct Answer Is B
For limited loads of a single branch circuit, No. 12 copper may be used, but in no case
can they be smaller than the branch-circuit conductors.
✔✔The allowable number of service disconnects can consist of up to _____ circuit
breakers.
A-three
B-four
C-five
D-six - ✔✔The Correct Answer Is D
The service disconnection means shall consist of not more than six circuit breakers.
NEC Section 230.71(A).
✔✔Multiconductor cables used for service drops must be attached to buildings or other
structures by _____.
A-tie wires
B-fittings approved for the purpose
C-16d nails or larger
, D-tapcons - ✔✔The Correct Answer Is B
An approved fitting, such as an insulator, is required for all such installations.
✔✔Service heads for overhead service-entrance conductors must be _____.
A-explosion-proof
B-raintight
C-waterproof
D-dust-proof - ✔✔The Correct Answer Is B
Service heads must be constructed and protected to prevent rain from interfering with
the successful operation of the service-entrance conductors. NEC Section 230.54(A).
✔✔Service-entrance cable must be supported within what distance from the service
head?
A-12 inches
B-18 inches
C-24 inches
D-36 inches - ✔✔The Correct Answer Is A
An SE cable strap or other approved fitting must be installed within 12 inches of the
service head.
✔✔Service-entrance cable must also be supported at intervals of _____.
A-2 feet
B-2-1/2 feet
C-3 feet
D-4-1/2 feet - ✔✔The Correct Answer Is B
Type SE cable must be supported at least every 2-1/2 feet (30 inches) to prevent sag or
collapse of the cable.
✔✔What clearance must service conductors have from windows, doors, porches, fire
escapes, or similar locations?
A-1 foot
B-2 feet
C-3 feet
D-4 feet - ✔✔The Correct Answer Is C
Service conductors installed as open conductors or multi-conductor cable without an
overall outer jacket shall have a clearance of not less than 3 feet from windows, doors,
porches, fire escapes, or similar locations. Conductors run above the top level of a
window, however, shall be permitted to be less than 3 feet. NEC Section 230.9
✔✔When installing a service head, the conductors of different potential should be
_____.
A-brought out through seperately bushed openings
B-brought out through the same bushed openings
C-brought out through the same unbushed openings
D-brought out through separately unbushed openings - ✔✔The Correct Answer Is A
