Journeyman Electrician Practice Test Questions and
Answers with Solutions UPDATED!!!
Conductors with _____ marked on the insulation are NOT
approved for use in a wet location. - ANSWER THHN
conductors with THHN insulation are approved for use in dry
and damp locations only and conductors with THWN, THHW,
and THW insulation are recognized for use in dry and wet
locations.
Given: A one-family dwelling unit with a demand load of 200
amperes is supplied with a 120/240 volt, single-phase, electrical
system from the local utility company. What is the MINIMUM
size aluminum THW conductors required for use as service-
entrance conductors for this residence? - ANSWER 4/0 AWG
one-family dwelling 120/240 volt, single-phase, service-
entrance conductors to be sized at an ampacity of not less than
83% of the service rating. Therefore, 200 amperes x 83% = 166
amperes; size 4/0 AWG THW aluminum conductors with an
allowable ampacity of 180 amperes should be selected for this
dwelling.
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Where a 150 kVA, single-phase transformer having a secondary
voltage of 120/240 is installed at a multi-family dwelling, the
full-load current rating, in amperes, of the secondary is _____. -
ANSWER 625 amperes
To find the full-load current rating of the single-phase
transformer apply the single-phase current formula as shown:I
= (150 kVA x 1000) / 240 volts = 15,000/240 = 625 amperes
Which one of the following listed circuit breakers is NOT a
standard ampere rating? - ANSWER 75 amperes
the standard ampere ratings for fuses and circuit breakers. A
circuit breaker with an ampere rating of 75 amperes is not a
standard ampere rating.
The MINIMUM length of free conductor to be left at each
junction box for the purpose of splicing conductors, or making
connections to illuminares or devices shall be _____ . - ANSWER
6 inches
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free conductor is to be left at each junction box for splices or
the connection of luminaires or devices. The intent of this rule
is to ensure enough conductor slack for the terminal
connections or splices to be made easily.
In general, overhead service-drop conductors shall NOT be
smaller than _____. - ANSWER 8 AWG copper
overhead service-drop conductors to be not smaller than 8
AWG copper or 6 AWG aluminum or copper-clad aluminum. Do
not get service-drop conductors, the overhead conductors
between the utility electric supply system and the service point,
confused with the service-entrance conductors, the conductors
from the service point from the utility company to the service
disconnecting means.
When a galvanized eye-bolt is to be used as the point of
attachment for an electrical service, the NEC requires the eye-
bolt to be installed NOT less than _____ above finished grade. -
ANSWER 10 ft.
provide adequate vertical clearance of the conductors and
prevent physical damage to the conductors and prevent