Journeyman Electrician Practice Test
100% ACCURATE!!
Conductors with _____ marked on the insulation are NOT approved for use in a wet location. -
ANSWERTHHN
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? -
ANSWER4/0 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.
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 _____. -
ANSWER625 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? - ANSWER75
amperes
provide adequate vertical clearance of the conductors and prevent physical damage to the
conductors and prevent persons from making accidental contact with the conductors which may
create a shock hazard or electrocution. In no case shall the point of attachment of the service-drop
conductors to be less than 10 ft. above finished grade.
Why is electrical continuity required for metallic conduit? - ANSWERTo establish an effective ground-
fault path and facilitate the operation of the over-current protective device.
, Electrical continuity is required for metallic conduit to establish an effective ground-fault path and
facilitate the operation of the overcurrent protective device.
In dwelling units, receptacle outlets installed for countertop surfaces, must be located above, but
NOT more than _____ above the countertop or work surface. - ANSWER20 inches
receptacle outlets installed for countertop or work surfaces in dwelling units may be located on or
above, but not more than 20 in. above the countertop or work surface. The intent of this rule is to
eliminate the use of unsightly extension cords (which reduces the amount of usable countertop
space) on the countertop or work surface to supply cord-and-plug connected appliances. Also,
receptacles located more than 20 inches above countertops or work surfaces may interfere with the
cabinetry to be installed.
When conductors are installed in a conduit or tubing nipple of _____ or less in length, the ampacity
adjustment factors for more than three (3) current-carrying conductors in the raceway, are not
required to be applied. - ANSWER24 inches
adjustment factors for more than three (3) current-carrying conductors in raceways shall not apply
where the raceway is not more than 24 inches in length. Where more than 3 current-carrying
conductors are installed in short lengths of conduit or tubing, the heating effect caused from the
additional conductors is insignificant therefore, the allowable ampacity of the conductors is not
greatly reduced.
In compliance with the NEC, the total marked rating of a 120-volt, cord-and-plug-connected room air
conditioner shall not exceed _____ of the rating of a branch circuit when lighting units, general-use
receptacles, or other appliances are supplied from the branch circuit. - ANSWER50%
the special provisions for room air conditioners which are (1) rated not over 250-volts ac, single-
phase and (2) which are cord-and-attachment plug connected. In order to prevent overloading the
branch circuit, as per Section 40.62(C), the total rating of the A/C unit shall not exceed 50% of the
rating of a branch circuit where lighting units, general-use receptacles or appliances are also
supplied.
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.
100% ACCURATE!!
Conductors with _____ marked on the insulation are NOT approved for use in a wet location. -
ANSWERTHHN
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? -
ANSWER4/0 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.
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 _____. -
ANSWER625 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? - ANSWER75
amperes
provide adequate vertical clearance of the conductors and prevent physical damage to the
conductors and prevent persons from making accidental contact with the conductors which may
create a shock hazard or electrocution. In no case shall the point of attachment of the service-drop
conductors to be less than 10 ft. above finished grade.
Why is electrical continuity required for metallic conduit? - ANSWERTo establish an effective ground-
fault path and facilitate the operation of the over-current protective device.
, Electrical continuity is required for metallic conduit to establish an effective ground-fault path and
facilitate the operation of the overcurrent protective device.
In dwelling units, receptacle outlets installed for countertop surfaces, must be located above, but
NOT more than _____ above the countertop or work surface. - ANSWER20 inches
receptacle outlets installed for countertop or work surfaces in dwelling units may be located on or
above, but not more than 20 in. above the countertop or work surface. The intent of this rule is to
eliminate the use of unsightly extension cords (which reduces the amount of usable countertop
space) on the countertop or work surface to supply cord-and-plug connected appliances. Also,
receptacles located more than 20 inches above countertops or work surfaces may interfere with the
cabinetry to be installed.
When conductors are installed in a conduit or tubing nipple of _____ or less in length, the ampacity
adjustment factors for more than three (3) current-carrying conductors in the raceway, are not
required to be applied. - ANSWER24 inches
adjustment factors for more than three (3) current-carrying conductors in raceways shall not apply
where the raceway is not more than 24 inches in length. Where more than 3 current-carrying
conductors are installed in short lengths of conduit or tubing, the heating effect caused from the
additional conductors is insignificant therefore, the allowable ampacity of the conductors is not
greatly reduced.
In compliance with the NEC, the total marked rating of a 120-volt, cord-and-plug-connected room air
conditioner shall not exceed _____ of the rating of a branch circuit when lighting units, general-use
receptacles, or other appliances are supplied from the branch circuit. - ANSWER50%
the special provisions for room air conditioners which are (1) rated not over 250-volts ac, single-
phase and (2) which are cord-and-attachment plug connected. In order to prevent overloading the
branch circuit, as per Section 40.62(C), the total rating of the A/C unit shall not exceed 50% of the
rating of a branch circuit where lighting units, general-use receptacles or appliances are also
supplied.
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.
