Journeyman Electrician (2024/25Nec)
With complete solution | Latest.
Conductors with _____ marked on the insulation are NOT approved for use in a wet II II II II II II II II II II II II II II
location.
II
a. THW II
b. THHW II
c. THHN II
d. THWN - THHN
II II II II II
As shown in Table 310.104(A), conductors with THHN insulation are approved for use in
II II II II II II II II II II II II II
dry and damp locations only and conductors with THWN, THHW, and THW insulation are
II II II II II II II II II II II II II II
recognized for use in dry and wet locations.
II II II II II II II II
Given: A one-family dwelling unit with a demand load of 200 amperes is supplied with a
II II II II II II II II II II II II II II II II II
120/240 volt, single-phase, electrical system from the local utility company. What is the
II II II II II II II II II II II II II
MINIMUM size aluminum THW conductors required for use as service-entrance
II II II II II II II II II II
conductors for this residence?
II II II II
a. 1/0 AWGII II
b. 4/0 AWGII II
c. 3/0 AWGII II
d. 2/0 AWG - 4/0 AWG
II II II II II II II
Section 310.15(B)(7)(1) permits one-family dwelling 120/240 volt, single-phase, service-
II II II II II II II II
entrance conductors to be sized at an ampacity of not less than 83% of the service rating.
II II II II II II II II II II II II II II II II
Therefore, 200 amperes x 83% = 166 amperesTable 310.15(B)(16) indicates size 4/0
II II II II II II II II II II II II
AWG THW aluminum conductors with an allowable ampacity of 180 amperes should be
II II II II II II II II II II II II II
selected for this dwelling.
II II II II
Where a 150 kVA, single-phase transformer having a secondary voltage of 120/240 is
II II II II II II II II II II II II II II
installed at a multi-family dwelling, the full-load current rating, in amperes, of the
II II II II II II II II II II II II II
secondary is _____.
II II II
a. 625 amperes
II II
b. 265 amperes
II II
c. 526 amperes
II II
d. 1250 amperes - 625 ampreres
II II II II II II II
To find the full-load current rating of the single-phase transformer apply the single-phase
II II II II II II II II II II II II
current formula as shown:
II II II II
I = (150 kVA x 1000) / 240 volts = 15,000/240 = 625 amperes
II II II II II II II II II II II II II
Which one of the following listed circuit breakers is NOT a standard ampere rating?a. 75
II II II II II II II II II II II II II II II II
amperes
II
b. 90 amperes
II II
c. 110 amperes
II II
d. 225 amperes - 75 amperes
II II II II II II II
, Table 240.6(A) illustrates the standard ampere ratings for fuses and circuit breakers. A
II II II II II II II II II II II II
circuit breaker with an ampere rating of 75 amperes is not a standard ampere rating.
II II II II II II II II II II II II II II II
The MINIMUM length of free conductor to be left at each junction box for the purpose of
II II II II II II II II II II II II II II II II II II
splicing conductors, or making connections to luminaires or devices shall be _____ .a. 4
II II II II II II II II II II II II II II
inches
II
b. 10 inches
II II
c. 8 inches
II II
d. 6 inches - 6 inches
II II II II II II II
As per Section 300.14 at least 6 in. of free conductor is to be left at each junction box for
II II II II II II II II II II II II II II II II II II II
splices or the connection of luminaires or devices. The intent of this rule is to ensure
II II II II II II II II II II II II II II II II
enough conductor slack for the terminal connections or splices to be made easily.
II II II II II II II II II II II II II
In general, overhead service-drop conductors shall NOT be smaller than _____.
II II II II II II II II II II II II
a. 2 AWG copper
II II II
b. 4 AWG copper
II II II
c. 6 AWG copper
II II II
d. 8 AWG copper - d. 8 AWG copper
II II II II II II II II II II
Section 230.23(B) requires overhead service-drop conductors to be not smaller than 8
II II II II II II II II II II II
AWG copper or 6 AWG aluminum or copper-clad aluminum. Do not get service-drop
II II II II II II II II II II II II II
conductors, the overhead conductors between the utility electric supply system and the
II II II II II II II II II II II II
service point, confused with the service-entrance conductors, the conductors from the
II II II II II II II II II II II
service point from the utility company to the service disconnecting means.
II II II II II II II II II II II
When a galvanized eye-bolt is to be used as the point of attachment for an electrical
II II II II II II II II II II II II II II II II II
service, the NEC requires the eye-bolt to be installed NOT less than _____ above finished
II II II II II II II II II II II II II II II
grade.
II
a. 8 ft.II II
b. 10 ft.
II II
c. 12 ft.
II II
d. 15 ft. - 10 Ft
II II II II II II II
The intent of Section 230.26 is to provide adequate vertical clearance of the conductors
II II II II II II II II II II II II II
and prevent physical damage to the conductors and prevent persons from making
II II II II II II II II II II II II
accidental contact with the conductors which may create a shock hazard or electrocution.
II II II II II II II II II II II II II
In no case shall the point of attachment of the service-drop conductors to be less than 10
II II II II II II II II II II II II II II II II II
ft. above finished grade.
II II II II
Why is electrical continuity required for metallic conduit?
II II II II II II II II II
a. To reduce voltage drop.
II II II II
b. To limit galvanic corrosion.
II II II II
c. To establish an effective ground-fault path and facilitate the operation of the overcurrent
II II II II II II II II II II II II II
protective device.
II II
d. To reduce electrolysis. - To establish an effective ground-fault path and facilitate the
II II II II II II II II II II II II II II II
operation of the overcurrent protective device.
II II II II II II
With complete solution | Latest.
Conductors with _____ marked on the insulation are NOT approved for use in a wet II II II II II II II II II II II II II II
location.
II
a. THW II
b. THHW II
c. THHN II
d. THWN - THHN
II II II II II
As shown in Table 310.104(A), conductors with THHN insulation are approved for use in
II II II II II II II II II II II II II
dry and damp locations only and conductors with THWN, THHW, and THW insulation are
II II II II II II II II II II II II II II
recognized for use in dry and wet locations.
II II II II II II II II
Given: A one-family dwelling unit with a demand load of 200 amperes is supplied with a
II II II II II II II II II II II II II II II II II
120/240 volt, single-phase, electrical system from the local utility company. What is the
II II II II II II II II II II II II II
MINIMUM size aluminum THW conductors required for use as service-entrance
II II II II II II II II II II
conductors for this residence?
II II II II
a. 1/0 AWGII II
b. 4/0 AWGII II
c. 3/0 AWGII II
d. 2/0 AWG - 4/0 AWG
II II II II II II II
Section 310.15(B)(7)(1) permits one-family dwelling 120/240 volt, single-phase, service-
II II II II II II II II
entrance conductors to be sized at an ampacity of not less than 83% of the service rating.
II II II II II II II II II II II II II II II II
Therefore, 200 amperes x 83% = 166 amperesTable 310.15(B)(16) indicates size 4/0
II II II II II II II II II II II II
AWG THW aluminum conductors with an allowable ampacity of 180 amperes should be
II II II II II II II II II II II II II
selected for this dwelling.
II II II II
Where a 150 kVA, single-phase transformer having a secondary voltage of 120/240 is
II II II II II II II II II II II II II II
installed at a multi-family dwelling, the full-load current rating, in amperes, of the
II II II II II II II II II II II II II
secondary is _____.
II II II
a. 625 amperes
II II
b. 265 amperes
II II
c. 526 amperes
II II
d. 1250 amperes - 625 ampreres
II II II II II II II
To find the full-load current rating of the single-phase transformer apply the single-phase
II II II II II II II II II II II II
current formula as shown:
II II II II
I = (150 kVA x 1000) / 240 volts = 15,000/240 = 625 amperes
II II II II II II II II II II II II II
Which one of the following listed circuit breakers is NOT a standard ampere rating?a. 75
II II II II II II II II II II II II II II II II
amperes
II
b. 90 amperes
II II
c. 110 amperes
II II
d. 225 amperes - 75 amperes
II II II II II II II
, Table 240.6(A) illustrates the standard ampere ratings for fuses and circuit breakers. A
II II II II II II II II II II II II
circuit breaker with an ampere rating of 75 amperes is not a standard ampere rating.
II II II II II II II II II II II II II II II
The MINIMUM length of free conductor to be left at each junction box for the purpose of
II II II II II II II II II II II II II II II II II II
splicing conductors, or making connections to luminaires or devices shall be _____ .a. 4
II II II II II II II II II II II II II II
inches
II
b. 10 inches
II II
c. 8 inches
II II
d. 6 inches - 6 inches
II II II II II II II
As per Section 300.14 at least 6 in. of free conductor is to be left at each junction box for
II II II II II II II II II II II II II II II II II II II
splices or the connection of luminaires or devices. The intent of this rule is to ensure
II II II II II II II II II II II II II II II II
enough conductor slack for the terminal connections or splices to be made easily.
II II II II II II II II II II II II II
In general, overhead service-drop conductors shall NOT be smaller than _____.
II II II II II II II II II II II II
a. 2 AWG copper
II II II
b. 4 AWG copper
II II II
c. 6 AWG copper
II II II
d. 8 AWG copper - d. 8 AWG copper
II II II II II II II II II II
Section 230.23(B) requires overhead service-drop conductors to be not smaller than 8
II II II II II II II II II II II
AWG copper or 6 AWG aluminum or copper-clad aluminum. Do not get service-drop
II II II II II II II II II II II II II
conductors, the overhead conductors between the utility electric supply system and the
II II II II II II II II II II II II
service point, confused with the service-entrance conductors, the conductors from the
II II II II II II II II II II II
service point from the utility company to the service disconnecting means.
II II II II II II II II II II II
When a galvanized eye-bolt is to be used as the point of attachment for an electrical
II II II II II II II II II II II II II II II II II
service, the NEC requires the eye-bolt to be installed NOT less than _____ above finished
II II II II II II II II II II II II II II II
grade.
II
a. 8 ft.II II
b. 10 ft.
II II
c. 12 ft.
II II
d. 15 ft. - 10 Ft
II II II II II II II
The intent of Section 230.26 is to provide adequate vertical clearance of the conductors
II II II II II II II II II II II II II
and prevent physical damage to the conductors and prevent persons from making
II II II II II II II II II II II II
accidental contact with the conductors which may create a shock hazard or electrocution.
II II II II II II II II II II II II II
In no case shall the point of attachment of the service-drop conductors to be less than 10
II II II II II II II II II II II II II II II II II
ft. above finished grade.
II II II II
Why is electrical continuity required for metallic conduit?
II II II II II II II II II
a. To reduce voltage drop.
II II II II
b. To limit galvanic corrosion.
II II II II
c. To establish an effective ground-fault path and facilitate the operation of the overcurrent
II II II II II II II II II II II II II
protective device.
II II
d. To reduce electrolysis. - To establish an effective ground-fault path and facilitate the
II II II II II II II II II II II II II II II
operation of the overcurrent protective device.
II II II II II II
