Download Journeyman Electrician Exercise Quiz: Electrical Code and Safety Practices and more Exams Electrical Engineering in PDF only on Docsity!
Journeyman Electrician Exercise Quiz
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 _____. - Correct Ans: โโ6 inches
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 _____. - Correct Ans: โโ8 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. - Correct Ans: โโ10 ft.
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? - Correct
Ans: โโTo 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. - Correct Ans: โโ20 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.
"overcurrent devices shall not be located over steps of a stairway." This requirement address a serious safety issue. No one should be required to stand on different treads on a stairway to replace, repair, maintain, install, troubleshoot, or reset overcurrent devices in a panelboard or switchboard located in a stairway.
Where a permanently installed outdoor swimming pool is located on residential or commercial properties, at least one (1) single-phase, 125-volt, 15- or 20-ampere receptacle shall be located not less than _____ from and not more than _____ from the inside wall of the
swimming pool. - Correct Ans: โโ6 feet - 20 feet
apply to the installation of wiring methods and equipment in or adjacent to permanently installed swimming pools.
each permanently installed swimming pool is to be provided with at least one (1) single-phase, 15- or 20-ampere, 125-volt, receptacle placed not closer than six (6) feet from the pool and not more than twenty (20) feet from the pool.
This requirement allows ordinary appliances such as a radio, to be safely plugged in and used near the pool, but avoids the need for extension cords in the pool vicinity. Be advised the receptacles must be provided with
Metal water pipes installed in or attached to a building or structure shall be bonded to _____.
a. the service equipment enclosure
b. the grounded conductor at the service
c. the grounding electrode conductor
d. any of the above - Correct Ans: โโAny of the above
requires metal water piping systems to be bonded to any of (1) the service entrance enclosure, (2) the grounded conductor at the service, (3) the grounding electrode conductor.Where mechanical and electrical connections are within equipment, a failure of electrical insulation can result in the connected piping systems becoming energized. For example, an insulation failure in an electrical circuit of a water heater could energize the metal water piping.Metal water piping systems must be bonded so that when a fault occurs between an ungrounded (hot) conductor and the piping, the potential difference between the two is minimized, thereby reducing the risk of electrical shock.Also, note where installed in or attached to a building or structure, all metal piping systems, including gas piping, that is likely to become energized shall be bonded to a grounded source.
When armored cable, Type AC, is installed in an accessible attic and is run parallel to the sides of rafters, studs, or floor joists, _____.
a. the cable shall be protected with running boards
b. the cable shall be protected by guard strips at least as high as the cable
c. either A or B
Single-conductor cable such as _____ and single-conductor cable listed and identified as solar photovoltaic (PV) wire are permitted for
use in PV source circuits within the PV array. - Correct Ans: โโUSE- 2
690 covers the wiring methods specified for use on solar photovoltaic (PV) systems arrays.
indicates open, single-conductors such as Type USE-2 and single- conductor cable listed and identified as PV wire are permitted foruse in PV source circuits within the PV array.
These conductors are evaluated and listed for use where exposed to sunlight and wet conditions.
For dwelling units, GFCI protection is required for all single-phase, 125-volt, 15- and 20-ampere receptacles installed within six (6) feet of the top inside edge of the bowl of sinks located in _____.
a. laundry rooms
b. bathrooms
c. garages
d. all of these areas - Correct Ans: โโAll of these areas
no matter what the location or room in a dwelling, where the 15- or 20-ampere, 125-volt eceptacles are installed within six (6) feet from
the top inside edge of the bowl of the sink, GFCI protection must be provided to prevent a ground-fault shock hazard.
For a building or structure where the meter enclosure is adjacent to the service disconnecting means, it is permitted to ground the meter enclosure to the _____ conductor on the load side of the service
disconnect if ground-fault protection is not provided. - Correct Ans:
โโGrounded
The meter enclosure to be grounded by connection on the load side of the service disconnect where (1) no ground-fault protection is installed, (2) the meter enclosure is adjacent to the service disconnecting means, and (3) the grounded service conductor is not smaller than the size specified
In a dwelling unit where a 125-volt, 15- or 20-ampere receptacle is located under the counter for an in-sink waste disposer, the receptacle must be provided with _____.
a. AFCI protection only
b. GFCI protection only
c. both AFCI and GFCI protection
d. neither AFCI nor GFCI protection - Correct Ans: โโBoth AFCI and GFCI protection
Because of the presence of water and grounded surfaces that contributes to a potential shock hazard
the permitted installation of busways. For busways in industrial establishments only, providing overcurrent protection at the point where the busway size is changed is not required if the busway having the smaller ampacity does not exceed fifty (50) feet in length and has an ampacity of at least one-third the rating of the overcurrent protection of the larger usway. 1/3 of 600 amperes = 200 amperes
When installing nonmetallic sheathed cable enclosed in an underground buried PVC conduit, the cable _____.
a. must be Type NMC
b. must be Type NMS
c. must be Type NMW
d. is prohibited - Correct Ans: โโIs prohibited
he inside of all raceways and enclosures located underground is classified as a wet location. The conductors and cables installed in underground installations must be of a type listed for use in wet locations.Restrictions of the use of non-metallic sheathed cable
NMC is permitted in dry, moist, and damp locations, but wet locations are not included in this list.
According to the NEC, fixed outdoor deicing and snow melting
equipment is to be considered as a _____ load. - Correct Ans:
โโContinuous
a continuous load is a load expected to continue for three (3) hours or more.The installation requirements for fixed outdoor electric deicing and snow melting equipment, fixed outdoor electric deicing and snow melting equipment shall be considered a continuous load.When sizing conductors and overcurrent protection for the fixed outdoor equipment you must take into consideration the equipment can operate over 3 hours, so it is considered a continuous load.
In regard to a commercial building, where a service-entrance conduit having a length of six (6) feet contains four (4) size 2 AWG THWN insulated copper current-carrying conductors, each of the
conductors have an allowable ampacity of _____. - Correct Ans:
โโ92 amperers
To solve this problem first locate the conductor size,and look under the copper THWN column with a temperature rating of 75ยฐC and note the ampacity of the conductors is 115 amperes. The table is based on an ambient temperature of 86ยฐC and not more than 3 current-carrying conductors in the raceway.
in this situation there are 4 current-carrying conductors in the raceway therefore, we must apply the correct adjustment factor (derating value)
R = 3.6 / 18 = 0.2 ohms
When an electrical circuit tested with ohmmeter, a short circuit is
indicated by a reading of ...................... - Correct Ans: โโZero
For stationary small motors rated less than .................., the branch
circuit over current device may serve as a controller. - Correct Ans:
โโ1/ 8 horse power
What is the demand factor applied in calculating feeder or service conductor load for a commercial kitchen having four electrical
equipment - Correct Ans: โโ80 %
Demand factor for kitchen equipment in other than dwelling unit shall be applied according to 220.56 table.
A 440 volts motor has a full load current of 34 amperes. what size
disconnecting means is required? - Correct Ans: โโ40 amperes
The rating of disconnecting means is 115% of full load current.34 * 1.15 = 39.1 amperes.The nearer rating is 40 amperes.
If two 4 ohm resistors are connected in series which are powered by 240 volts power source, what is the current flow across one 4 ohm
resistor? - Correct Ans: โโ30 amperes
Total resistance of the circuit = 4 + 4 = 8 ohms
Current flow in the circuit = 240 /8 = 30 amperes
In series circuit flow in the circuit elements is same. so 30 amperes current will flow in both series resistors.
What is the minimum size of THWN conductors required for single
phase 10 HP motor connected to 240 volts supply? - Correct Ans:
โโ6 AWG THWN Copper
FLI current of single phase 10 HP motor at 230 volts = 50 amperes
Minimum conductor ampacity = 50 * 125% = 62.5 amperes
6 AWG THWN Copper with 65 amperes capacity at 75 0C is suitable conductor for the motor
In a metal wire-ways, the distance between supports shall not
exceed .............. ft. - Correct Ans: โโ 10
Underground wiring shall be installed in which of the following conduit
a.)Threaded rigid metal
If a 230 volts load is connected to 240 volts power source, what is the minimum voltage that can be supplied to load as recommended
by NEC? - Correct Ans: โโ228 volts
When the single phase air conditioner rating is less than .......... at 240 volts can be considered as single motor unit in determining
branch circuit conditions. - Correct Ans: โโ40 amperes
What is the low voltage contact limit for sinusoidal AC? - Correct
Ans: โโ15 Volts RMS
Flexible cards may not be used in the following locations .......... -
Correct Ans: โโTo replace a fixed wiring of a structure
What is the minimum percentage rated voltage that a storage
battery should supply the emergency load? - Correct Ans: โโ87 1/ %
The vertically run metal wire-ways shall be surely supported at intervals not exceeding ............. ft of wire way and shall not have
more than one joint between supports. - Correct Ans: โโ 15
The interior of any dip tank can be considered as ...................
location - Correct Ans: โโClass1, Division
Should ungrounded ducts or conduits should be sealed before
entering buildings? - Correct Ans: โโyes, to prevent unwanted gases entry in buildings
A continuous load is load where the maximum current is expected to
continue for ............ hours or more. - Correct Ans: โโ 3
Conductors with _____ marked on the insulation are NOT approved
for use in a wet location. - Correct Ans: โโTHHN
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? - Correct Ans: โโ4/0 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
