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NCCER JOURNEYMAN ELECTRICIAN
PRACTICE TEST QUESTIONS WITH
CORRECT ANSWERS LATEST UPDATE
Conductors with _____ marked on the insulation are NOT approved for use in a wet location. - correct 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? - correct 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.
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 _____. - correct 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
- / 240 volts = 15,000/240 = 625 amperes Which one of the following listed circuit breakers is NOT a standard ampere rating? - correct 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 _____. - correct answer- 6 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
Why is electrical continuity required for metallic conduit? - correct answer-To 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 answer-20 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. - correct answer-24 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. - correct answer-50% 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. What shall not be located over the steps of a stairway? - correct answer-overcurrent devices
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 answer-Any 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 d. neither guard strips nor running boards shall be required - correct answer-neither 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. Generally, in a movie theater the manual switch for controlling the emergency lighting systems is permitted to be located _____. - correct answer-in 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
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 answer-All 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 answer-Grounded 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 answer-Both AFCI and GFCI protection Because of the presence of water and grounded surfaces that contributes to a potential shock hazard any 125-volt, 15- or 20-ampere receptacle installed within six (6) feet of a sink is required to be GFCI protected. Section 210.12(A) verifies AFCI protection is required for all 120-volt, 15- or 20- ampere branch-circuits that supply outlets in kitchens in dwellings.AFCI devices are designed to determine resistance to unwanted tripping due to the presence of arcing that occurs in utilization equipment under normal operating conditions or to a loading condition that closely mimics an arcing fault. Where a 125-volt, 15-ampere receptacle is connected to a 120- volt branch circuit supplying two (2) or more receptacles or
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 answer-Is 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 answer- Continuous 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 answer-92 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) amperes x 80% (adjustment factor) = 92 amperes What material should not be used for Grounding electrodes. - correct answer-Aluminum
R = 3.6 / 18 = 0.2 ohms When an electrical circuit tested with ohmmeter, a short circuit is indicated by a reading of ...................... - correct answer-Zero For stationary small motors rated less than .................., the branch circuit over current device may serve as a controller. - correct answer-1/ 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 answer-80 % 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 answer-40 amperes The rating of disconnecting means is 115% of full load current.
- 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 answer-30 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 answer-6 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
All 15,20 amperes receptacle outlets installed in bathrooms of dwelling units shall always require ........................................... - correct answer-Ground fault circuit interceptor If the panel board rating is 100 amperes, what shall be the over current device rating located in panel board? - correct answer- less 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? - correct answer-228 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 answer-40 amperes
What is the low voltage contact limit for sinusoidal AC? - correct answer-15 Volts RMS Flexible cards may not be used in the following locations .......... - correct answer-To replace a fixed wiring of a structure What is the minimum percentage rated voltage that a storage battery should supply the emergency load? - correct answer- 87 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. - correct answer- 15 The interior of any dip tank can be considered as ................... location - correct answer-Class1, Division Should ungrounded ducts or conduits should be sealed before entering buildings? - correct answer-yes, to prevent unwanted gases entry in buildings
