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Journeyman Electrician Practice Test
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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/ 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? - ANSWER 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.
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 d. neither guard strips nor running boards shall be required - ANSWERneither guard strips nor running boards shall be required where the armored cable is installed parallel to the sides of rafters, studs or floor joists, neither guard strips nor running boards shall be required to protect the cable in accessible attics. if the cables run across the top of the floor joists in an attic that is not accessible by permanent studs or ladders, protection of the cable is required where within six (6) feet of the nearest edge of the scuttle hole or attic entrance. 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 - ANSWERAny of the above Generally, in a movie theater the manual switch for controlling the emergency lighting systems is permitted to be located _____. - ANSWERin an accessible location in the lobby apply buildings used as a theater or for a similar purpose. Section 520.8 mandates the control of emergency systems in theaters to comply with the rules set forth in Article 700; Part V of Article 700 applies to the control of emergency lighting circuits. Section 700.21 does not permit a manual control switch for emergency lighting to be placed in a motion picture projection booth or on a stage or platform; the switch shall be located in the lobby or at a convenient accessible location.Emergency lighting systems are designed and installed to maintain a specific degree of illumination for means of egress of the building in the event of fire, or similar emergency, or if the normal power supply fails. 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. - ANSWERUSE- 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 - ANSWERAll of these areas
In industrial establishments only, when a 200-ampere rated busway is tapped from a 600-ampere rated busway, what is the maximum permitted length of the 200-ampere busway where overcurrent protection is not provided for the 200-ampere busway? - ANSWER50 ft 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 - ANSWERIs 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. - ANSWERContinuous 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 _____. - ANSWER92 amperers
To solve this problem first locate the conductor size,and look under the copper THWN column with a temperature rating of 75°C and note the ampacity of the conductors is 115 amperes. The table is based on an ambient temperature of 86°C 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) 2 AWG THWN ampacity = 115 amperes (before derating)115 amperes x 80% (adjustment factor) = 92 amperes What material should not be used for Grounding electrodes. - ANSWERAluminum For a 300 ampere electrical circuit, what is the minimum size copper equipment grounding conductor as per NEC? - ANSWER4 awg 4 AWG is the minimum size wire for a 300 ampere circuit What is the minimum size secondary conductor required for a 2 wire 480 volts/ 120 volts transformer rated at 2.3 KVA with 750C temperature at terminals? - ANSWER14 AWG Secondary transformer current = 2300 / 120 = 19.16 amperes The suitable conductor is 14 AWG with 20 amperes capacity at 750C What is the resistance of the conductor if the conductor voltage drop is 3.6 volts and current flowing through conductor is 18 amperes? - ANSWER0.2 ohms Conductor voltage drop = 3.6 volts I R = 3.6 volts R = 3.6 / 18 = 0.2 ohms
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. - ANSWER Underground wiring shall be installed in which of the following conduit a.)Threaded rigid metal b.)Threaded steal intermediate metal c.)All options are correct .)PVC - ANSWERAll options are correct What is the resistance of 80 watt Light bulb rated at 120 volts? - ANSWER180 ohms When branch circuits used at outside, the size of overhead conductors for 600 volts or less, for spans upto 50 feet, shall not be less than ............. copper. - ANSWERNO 10 For Copper it is NO.10for aluminum it is NO 8 All 15,20 amperes receptacle outlets installed in bathrooms of dwelling units shall always require ........................................... - ANSWERGround fault circuit interceptor If the panel board rating is 100 amperes, what shall be the over current device rating located in panel board? - ANSWERless than 100 amperes The over current device rating must not be greater than panel board rating in which it is located 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? - ANSWER228 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. - ANSWER40 amperes
What is the low voltage contact limit for sinusoidal AC? - ANSWER15 Volts RMS Flexible cards may not be used in the following locations .......... - ANSWERTo replace a fixed wiring of a structure What is the minimum percentage rated voltage that a storage battery should supply the emergency load? - ANSWER87 1/2 % 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. - ANSWER The interior of any dip tank can be considered as ................... location - ANSWERClass1, Division Should ungrounded ducts or conduits should be sealed before entering buildings? - ANSWERyes, to prevent unwanted gases entry in buildings A continuous load is load where the maximum current is expected to continue for ............ hours or more. - ANSWER
