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NEC Quiz
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NEC Quiz

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Questions and Answers

Which of the following is NOT considered a receptacle outlet required by 210.52?

  • Switched receptacle
  • Wall switch
  • Controlled receptacle outlet
  • Occupancy sensor (correct)
  • Where should at least one lighting outlet controlled by a listed wall-mounted control device be installed?

  • In kitchens, laundry areas, and bathrooms
  • On the exterior side of outdoor entrances or exits with grade-level access
  • In hallways, stairways, attached garages, and detached garages (correct)
  • In the basement interior within 1.5 m (5 ft) horizontally of the bottommost stairway riser
  • In which areas are occupancy sensors permitted to be used for switching lighting outlets?

  • Attached garages and detached garages
  • Habitable rooms, kitchens, and bathrooms (correct)
  • Hallways and stairways
  • Kitchens and bathrooms
  • Which conductors need to be identified by polarity at termination, connection, and splice points in a feeder supplied from a dc system operating at more than 60 volts?

    <p>Ungrounded conductors of 4 AWG or larger</p> Signup and view all the answers

    Where should the documentation or permanent posting of the conductor method be located?

    <p>At each feeder panelboard or similar feeder distribution equipment</p> Signup and view all the answers

    What is the purpose of marking tape or ta in a dc system?

    <p>To indicate the direction of current flow</p> Signup and view all the answers

    Which type of systems are covered by the ground-fault protection requirement mentioned in the text?

    <p>Wye-connected systems operating over 150 volts to ground and not more than 600 volts phase-to-phase</p> Signup and view all the answers

    Under what condition is ground-fault protection of feeder equipment not required?

    <p>If protection is provided on an upstream feeder or at the service</p> Signup and view all the answers

    What is the purpose of additional levels of ground-fault protection for feeders?

    <p>To ensure that a single ground fault does not deenergize the whole electrical system</p> Signup and view all the answers

    What is the purpose of identifying ungrounded feeder conductors by system and phase?

    <p>To ensure consistent identification throughout the premises</p> Signup and view all the answers

    What is the demand factor permitted for the neutral load in excess of 200 amperes on a 3-phase, 4-wire system?

    <p>70 percent</p> Signup and view all the answers

    When calculating the maximum unbalanced load for feeders supplying clothes dryers, household ranges, wall-mounted ovens, and counter-mounted cooking units, what percentage of the load on the ungrounded conductors is required to be considered?

    <p>70 percent</p> Signup and view all the answers

    When does a neutral conductor need to be counted as a current-carrying conductor?

    <p>When it serves a load consisting of harmonic currents</p> Signup and view all the answers

    What type of circuits are permitted to be tapped from the ungrounded conductors of circuits having a grounded neutral conductor?

    <p>Both two-wire dc circuits and AC circuits of two or more ungrounded conductors</p> Signup and view all the answers

    According to the text, where is a listed wall-mounted control device required for lighting outlets in an interior stairway with six or more risers between floor levels?

    <p>At each floor level and at each landing level</p> Signup and view all the answers

    According to the text, when is dimmer control of lighting outlets in an interior stairway permitted?

    <p>Only when the control devices can provide dimming control to maximum brightness</p> Signup and view all the answers

    According to the text, what is the exception to the requirement of a lighting outlet in a guest room or guest suite?

    <p>Receptacles controlled by a listed wall-mounted control device</p> Signup and view all the answers

    According to the text, where should a lighting outlet containing a switch or controlled by a wall switch or listed wall-mounted control device be installed in attics and underfloor spaces, utility rooms, and basements?

    <p>At each entry that permits access to the attic and underfloor space, utility room, or basement</p> Signup and view all the answers

    Which formula can be used to determine the voltage drop in a 3-wire ac single-phase circuit with a balanced load at 100 percent power factor?

    <p>$VD = 0.866 \times L \times R \times I$</p> Signup and view all the answers

    What is the relationship between the voltage drop in a 3-phase circuit and the voltage drop calculated by the formula for a 3-wire ac single-phase circuit?

    <p>The voltage drop in a 3-phase circuit is 0.866 times the voltage drop calculated by the formula.</p> Signup and view all the answers

    What is the minimum size of the feeder circuit grounded conductor required by the code?

    <p>The size of the feeder circuit grounded conductor shall not be smaller than the equipment grounding conductor size required by 250.122.</p> Signup and view all the answers

    What is the minimum ampacity of the feeder conductor in relation to the service conductors for a feeder carrying the total load supplied by service conductors with an ampacity of 55 amperes or less?

    <p>The feeder conductor ampacity shall be equal to that of the service conductors.</p> Signup and view all the answers

    Which type of conductors are required to be sized based on 125 percent of the continuous load?

    <p>Feeder phase conductors</p> Signup and view all the answers

    What is the maximum unbalanced load on a feeder neutral if the maximum unbalanced load on the ungrounded conductors is 200 amperes and the load is considered continuous?

    <p>200 amperes</p> Signup and view all the answers

    What is the maximum allowable voltage drop at the farthest outlet of power, heating, and lighting loads for feeders and branch circuits?

    <p>5 percent</p> Signup and view all the answers

    What is the effect of an applied voltage of 10 percent below rating on fluorescent light output?

    <p>15 percent decrease</p> Signup and view all the answers

    According to the text, what is the purpose of Exception No. 3?

    <p>To exempt feeder grounded/neutral conductors from being sized based on 125 percent of the continuous load</p> Signup and view all the answers

    According to the text, how should the ampacity of the intervening segment be determined?

    <p>By using the ampacity parameters that apply over the length of the segment</p> Signup and view all the answers

    According to the text, what is the purpose of sizing the two segments at the terminations of the feeder?

    <p>To accommodate the effects of continuous loading on the termination devices</p> Signup and view all the answers

    According to the text, what is the purpose of sizing the intervening segment in accordance with the ampacity requirements for the conductor?

    <p>To accommodate the maximum current, whether or not any portion of that current is continuous</p> Signup and view all the answers

    Which type of occupancy has a demand factor of 35% for the lighting load over 120,000 volt-amperes?

    <p>Hotels and motels</p> Signup and view all the answers

    For show-window lighting, what is the minimum load required per linear meter?

    <p>660 volt-amperes</p> Signup and view all the answers

    What is the demand factor for the lighting load over 100,000 volt-amperes in hotels and motels?

    <p>35%</p> Signup and view all the answers

    Which of the following is NOT an approved means of identifying positive ungrounded conductors of 6 AWG or smaller in a dc system?

    <p>A continuous red stripe on the insulation</p> Signup and view all the answers

    What is the maximum interval for repeating the imprinted plus signs or the word POSITIVE on the insulation of positive ungrounded conductors of 6 AWG or smaller in a dc system?

    <p>610 mm (24 in.)</p> Signup and view all the answers

    Where should the identification methods for conductors originating within each feeder panelboard or similar feeder distribution equipment be documented or permanently posted?

    <p>At each feeder panelboard or similar feeder distribution equipment</p> Signup and view all the answers

    According to the text, where should a surge-protective device (SPD) be installed?

    <p>In or adjacent to distribution equipment</p> Signup and view all the answers

    According to the text, what type of surge-protective device (SPD) is required?

    <p>Type 1 or Type 2</p> Signup and view all the answers

    According to the text, what is the minimum nominal discharge current rating (In) for surge-protective devices (SPDs)?

    <p>10kA</p> Signup and view all the answers

    According to the text, where should barriers be placed to prevent inadvertent contact with energized busbars or terminals?

    <p>In panelboards, switchboards, switchgear, or motor control centers</p> Signup and view all the answers

    Which of the following is NOT considered a general lighting load by non-dwelling occupancy type according to Table 220.42(A)?

    <p>Club</p> Signup and view all the answers

    In office buildings, how should the receptacle loads be calculated?

    <p>The larger of the two options</p> Signup and view all the answers

    According to the text, when is ground-fault protection of feeder equipment not required?

    <p>When the feeder is supplying a 3-phase, 4-wire system</p> Signup and view all the answers

    What is the maximum allowable voltage drop at the farthest outlet of power, heating, and lighting loads for feeders and branch circuits?

    <p>5%</p> Signup and view all the answers

    Which of the following appliances are load calculations permitted for as specified in 220.54 and 220.55?

    <p>All of the above</p> Signup and view all the answers

    What is the minimum load calculation for heavy-duty lampholders?

    <p>600 volt-amperes</p> Signup and view all the answers

    How should the load calculation for show windows be determined?

    <p>Both A and B</p> Signup and view all the answers

    What is the minimum load calculation for fixed multioutlet assemblies used in other than dwelling units or the guest rooms or guest suites of hotels or motels?

    <p>All of the above</p> Signup and view all the answers

    Which of the following is NOT a requirement for calculating branch-circuit loads according to the text?

    <p>Using the total watts of lamps to calculate the load for lighting units with ballasts or transformers</p> Signup and view all the answers

    What is the maximum load allowed on a branch circuit under the conditions specified in the text?

    <p>The sum of the maximum loads specified in 220.11(A) through (C)</p> Signup and view all the answers

    What is the minimum load required for each outlet for general-use receptacles and outlets not used for general illumination in all occupancies?

    <p>The load calculated in 220.14(A) through (K)</p> Signup and view all the answers

    What is the purpose of rounding calculations to the nearest whole ampere with decimal fractions smaller than 0.5 dropped according to the text?

    <p>To simplify the load calculation process</p> Signup and view all the answers

    According to the text, what is the minimum unit load for one-family, two-family, and multifamily dwellings?

    <p>33 volt-amperes/m2</p> Signup and view all the answers

    Which outlets are included in the minimum unit load calculation for one-family, two-family, and multifamily dwellings?

    <p>All of the above</p> Signup and view all the answers

    According to the text, how should the load calculation for other outlets not covered in 220.14(A) through (J) be determined?

    <p>180 volt-amperes per outlet</p> Signup and view all the answers

    What is the minimum nominal discharge current rating (In) for surge-protective devices (SPDs) according to the text?

    <p>20 kiloamperes</p> Signup and view all the answers

    According to the text, what is the minimum unit load for one-family dwellings?

    <p>33 volt-amperes/m2</p> Signup and view all the answers

    According to the text, what is the maximum number of receptacle outlets permitted on a 15-ampere branch circuit in dwelling occupancies?

    <p>10 outlets</p> Signup and view all the answers

    According to the text, what is the calculated load from 220.14(I) for receptacle outlets in office buildings?

    <p>11 volt-amperes/m2</p> Signup and view all the answers

    According to the text, what is the minimum ampacity of the feeder conductor in relation to the service conductors for a feeder carrying the total load supplied by service conductors with an ampacity of 55 amperes or less?

    <p>Not less than the sum of the loads on the branch circuits supplied</p> Signup and view all the answers

    According to the text, what is the minimum load calculation for heavy-duty lampholders?

    <p>100 percent of the first 2.2 kW</p> Signup and view all the answers

    According to the text, how should the load calculation for show windows be determined?

    <p>Based on the number of outlets in the show window area</p> Signup and view all the answers

    According to the text, where should a surge-protective device (SPD) be installed?

    <p>At the service entrance</p> Signup and view all the answers

    According to Table 220.54, what is the demand factor for 13 household electric clothes dryers?

    <p>47%</p> Signup and view all the answers

    What is the maximum demand in kilowatts (kW) for 6 household electric cooking appliances with a rating of 31/2 kW through 83/4 kW?

    <p>21 kW</p> Signup and view all the answers

    What is the demand factor for 5 household electric ranges individually rated over 12 kW but not more than 27 kW?

    <p>80%</p> Signup and view all the answers

    What is the maximum demand in kilowatts (kW) for 22 household electric cooking appliances with a rating of 61 and over?

    <p>32 kW</p> Signup and view all the answers

    According to Table 220.56, what is the demand factor for 6 units of other kitchen equipment in a commercial setting?

    <p>80%</p> Signup and view all the answers

    For commercial electric cooking appliances, what is the demand factor applied to the appliance nameplate rating?

    <p>90%</p> Signup and view all the answers

    According to 220.57, how is the load for Electric Vehicle Supply Equipment (EVSE) calculated?

    <p>Nameplate rating</p> Signup and view all the answers

    When calculating the total load of a feeder or service, what should be used for a motor or air-conditioning load that is not the largest of the noncoincident loads?

    <p>125% of the motor load</p> Signup and view all the answers

    According to the text, what is the demand factor for household electric clothes dryers in a dwelling unit(s)?

    <p>75%</p> Signup and view all the answers

    How should the load calculation for small-appliance circuit loads in a dwelling unit be determined?

    <p>At 100% of the total connected load</p> Signup and view all the answers

    What is the minimum load calculation for each 2-wire small-appliance branch circuit in a dwelling unit?

    <p>1500 volt-amperes</p> Signup and view all the answers

    According to the text, what is the purpose of applying a demand factor of 75% to the nameplate rating load of four or more appliances rated 1/4 hp or greater, or 500 watts or greater, that are fastened in place and served by the same feeder or service in a dwelling unit?

    <p>To reduce the number of small motor-operated appliance loads</p> Signup and view all the answers

    Which of the following is true regarding the demand factors for household cooking appliances?

    <p>The demand factors are based on the diversified use of household appliances</p> Signup and view all the answers

    When should Column C be used for calculating the branch-circuit load for household cooking appliances?

    <p>When the demand factors specified in Column A or Column B are not applicable</p> Signup and view all the answers

    What is the branch-circuit load for one wall-mounted oven or one counter-mounted cooking unit?

    <p>The equivalent of one range</p> Signup and view all the answers

    Under what conditions can the nameplate ratings of multiple appliances be added together for calculating the branch-circuit load?

    <p>When the appliances are located in the same room and supplied from a single branch circuit</p> Signup and view all the answers

    Which of the following is NOT a condition where the capacity of a neutral or grounded conductor of a feeder or service is not permitted to be reduced?

    <p>The load of the electric-discharge lighting, data-processing, or similar equipment on the feeder neutral consists of less than half the total load</p> Signup and view all the answers

    What is the maximum unbalanced load on a feeder neutral if the maximum unbalanced load on the ungrounded conductors is 200 amperes and the load is considered continuous?

    <p>410 amperes</p> Signup and view all the answers

    What is the demand factor for the lighting load over 100,000 volt-amperes in hotels and motels?

    <p>50%</p> Signup and view all the answers

    What is the purpose of rounding calculations to the nearest whole ampere with decimal fractions smaller than 0.5 dropped according to the text?

    <p>To prevent overloading of conductors</p> Signup and view all the answers

    According to the text, how much additional load is required for every 600 mm (2 ft) of lighting track for track lighting in other than dwelling units or guest rooms or guest suites of hotels or motels?

    <p>150 volt-amperes</p> Signup and view all the answers

    According to the text, how should the load be considered if multicircuit track is installed for track lighting in other than dwelling units or guest rooms or guest suites of hotels or motels?

    <p>The load shall be considered to be divided equally between the track circuits.</p> Signup and view all the answers

    According to the text, what is the exception to the requirement of a lighting outlet in a guest room or guest suite?

    <p>If the guest room or guest suite is equipped with a device that limits the current to the lighting outlet.</p> Signup and view all the answers

    Which of the following is NOT a requirement for calculating branch-circuit loads according to the text?

    <p>Consideration of track lighting</p> Signup and view all the answers

    What is the minimum nominal discharge current rating (In) for surge-protective devices (SPDs) according to the text?

    <p>1000 amperes</p> Signup and view all the answers

    According to the text, where should barriers be placed to prevent inadvertent contact with energized busbars or terminals?

    <p>Around the perimeter of the electrical room</p> Signup and view all the answers

    According to the text, what is the maximum interval for repeating the imprinted plus signs or the word POSITIVE on the insulation of positive ungrounded conductors of 6 AWG or smaller in a dc system?

    <p>Every 3 feet</p> Signup and view all the answers

    According to the text, what is the minimum size of the feeder circuit grounded conductor required by the code?

    <p>6 AWG</p> Signup and view all the answers

    According to the text, where should at least one lighting outlet controlled by a listed wall-mounted control device be installed?

    <p>In every room</p> Signup and view all the answers

    Which of the following is NOT included in the calculation of the heating and air-conditioning load in kVA?

    <p>65% of nameplate rating of electric space heating</p> Signup and view all the answers

    What is the additional load required for each 2-wire, 20-ampere small-appliance branch circuit and each laundry branch circuit in volt-amperes?

    <p>1500 volt-amperes</p> Signup and view all the answers

    What is the formula for calculating the total load in kVA?

    <p>Total load = 0 kVA + 40% of remainder + 1500 volt-amperes + nameplate rating of appliances</p> Signup and view all the answers

    According to Table 220.84(B), what is the demand factor for a multifamily dwelling unit with 9 dwelling units?

    <p>44%</p> Signup and view all the answers

    What is the calculated load for general lighting and general-use receptacles in a school building with a total area of 500 square meters?

    <p>16,500 volt-amperes</p> Signup and view all the answers

    According to Table 220.86, what is the demand factor for feeders and service conductors for schools with a connected load of 250,000 volt-amperes per square meter?

    <p>25%</p> Signup and view all the answers

    When two dwelling units are supplied by a single feeder or service, which load should be used if the calculated load for three identical units exceeds the calculated load under Part III of Article 220?

    <p>The load for the smaller unit</p> Signup and view all the answers

    According to Table 220.83(A), what is the percentage of load for the remainder of load after the first 8 kVA for existing and additional new loads without additional air-conditioning or electric space-heating equipment?

    <p>40%</p> Signup and view all the answers

    According to Table 220.83(B), what is the percentage of load for the remainder of all other loads after the first 8 kVA for existing and additional new loads with additional air-conditioning or electric space-heating equipment?

    <p>40%</p> Signup and view all the answers

    According to 220.84(A)(2), what is the maximum calculated load that can be used when the calculated load for multifamily dwellings without electric cooking exceeds that calculated under Part IV for the identical load plus electric cooking?

    <p>The lesser of the two calculated loads</p> Signup and view all the answers

    According to 220.84(A)(3), how is the neutral load determined for feeders and service conductors when the load is calculated using the optional calculation for multifamily dwellings?

    <p>By using 220.61</p> Signup and view all the answers

    According to Table 220.110(1), what is the demand factor for receptacles in Category 2 patient care spaces with a load of 8000 volt-amperes?

    <p>25%</p> Signup and view all the answers

    According to Table 220.103, how should the total load of a farm be calculated if there are two farm equipment buildings with loads having the same function?

    <p>Combine the loads and calculate as a single load</p> Signup and view all the answers

    According to Table 220.120, what is the demand factor for shore power receptacle loads in marinas with 10-14 receptacles?

    <p>70%</p> Signup and view all the answers

    According to 220.110, what is the demand factor for receptacles in Category 4 patient care spaces with a load of 15,000 volt-amperes?

    <p>75%</p> Signup and view all the answers

    According to the text, when is ground-fault protection of feeder equipment not required?

    <p>When the feeder has overcurrent protection in accordance with 240.4</p> Signup and view all the answers

    According to the text, what is the maximum demand in kilowatts (kW) for 6 household electric cooking appliances with a rating of 3 1/2 kW through 8 3/4 kW?

    <p>20.5 kW</p> Signup and view all the answers

    According to Table 220.88, what is the permitted load calculation for service and feeder conductors for new restaurants with a total connected load of 326-800 kVA?

    <p>50% (amount over 325) + 172.5 kVA</p> Signup and view all the answers

    According to the text, how should the load calculation for small-appliance circuit loads in a dwelling unit be determined?

    <p>By multiplying the total connected load by a demand factor</p> Signup and view all the answers

    Which of the following is NOT an example of an outside feeder or branch circuit, as mentioned in the text?

    <p>Conductors supplying a residential building</p> Signup and view all the answers

    According to the text, what is the minimum size of copper conductors for overhead spans up to 15 m (50 ft) in length?

    <p>10 AWG</p> Signup and view all the answers

    According to the text, what is the insulation requirement for open individual (aerial) overhead conductors within 3.0 m (10 ft) of any building or structure other than supporting poles or towers?

    <p>Insulated for the nominal voltage</p> Signup and view all the answers

    What is the purpose of the messenger wire in overhead spans, as mentioned in the text?

    <p>To provide mechanical strength to support the weight of the conductors</p> Signup and view all the answers

    Which of the following is NOT an approved means of attaching festoon lighting to buildings or structures?

    <p>Messenger wire</p> Signup and view all the answers

    Which of the following is NOT a permitted method for installing outside wiring on surfaces of buildings or other structures?

    <p>Type UF cable</p> Signup and view all the answers

    Feeder and branch-circuit conductors entering or exiting buildings or structures shall be installed in accordance with which section?

    <p>225.11</p> Signup and view all the answers

    According to 225.14(A), how much separation is required between open conductors of other circuits or systems?

    <p>100 mm (4 in.)</p> Signup and view all the answers

    According to 225.16(B), what is the minimum separation required for conductors on poles if they are not placed on racks or brackets?

    <p>300 mm (1 ft)</p> Signup and view all the answers

    According to 225.18(3), what is the minimum clearance required for overhead spans of open conductors and open multiconductor cables over residential property and driveways, where the voltage does not exceed 300 volts to ground?

    <p>3.0 m (10 ft)</p> Signup and view all the answers

    According to 225.19(D), what are the requirements for clearances from windows, doors, fire escapes, and similar areas where overhead conductors are subject to contact by persons?

    <p>3.0 m (10 ft)</p> Signup and view all the answers

    According to the text, what is the purpose of staggering the connections to the circuit wires when attaching outdoor lampholders as pendants?

    <p>To reduce the risk of shock hazards</p> Signup and view all the answers

    According to the text, what type of conductors should be used when attaching lampholders with terminals that puncture the insulation and make contact with the conductors?

    <p>Stranded conductors</p> Signup and view all the answers

    According to the text, why should vegetation such as trees not be used for support of overhead conductor spans?

    <p>To prevent chafing or degradation of the conductor insulation</p> Signup and view all the answers

    According to the text, how should a raceway entering a building or structure from outside be sealed?

    <p>With sealants identified for use with cable insulation, conductor insulation, bare conductor, shield, or other components</p> Signup and view all the answers

    According to the text, what is the minimum vertical clearance required above a roof surface for overhead spans of open conductors and open multiconductor cables?

    <p>2.6 m (8 ft 6 in.)</p> Signup and view all the answers

    According to the text, what is the minimum clearance required from signs, chimneys, radio and television antennas, tanks, and other nonbuilding or nonbridge structures for overhead spans of open conductors and open multiconductor cables?

    <p>3 ft</p> Signup and view all the answers

    According to the text, what is the minimum horizontal clearance required for overhead spans of open conductors and open multiconductor cables?

    <p>3 ft</p> Signup and view all the answers

    According to the text, what is the minimum vertical clearance required above or within 900 mm (3 ft) horizontally of platforms, projections, or surfaces that will permit personal contact for final spans of feeders or branch circuits?

    <p>2.6 m (8 ft 6 in.)</p> Signup and view all the answers

    According to the text, where are additional feeders or branch circuits permitted to supply electric vehicle power transfer systems?

    <p>Docking facilities and piers</p> Signup and view all the answers

    According to the text, how many feeders are permitted where feeder conductors originate in the same panelboard, switchboard, or other distribution equipment, and each feeder terminates in a single disconnecting means?

    <p>Not more than six feeders</p> Signup and view all the answers

    According to the text, under what conditions are additional feeders or branch circuits permitted for multiple-occupancy buildings?

    <p>When there is no space available for supply equipment accessible to all occupants</p> Signup and view all the answers

    According to the text, where are additional feeders or branch circuits permitted for different voltages, frequencies, or phases, or for different uses?

    <p>Systems designed for connection to multiple sources of supply for the purpose of enhanced reliability</p> Signup and view all the answers

    According to the text, how many switches or circuit breakers are allowed in a single enclosure for the disconnecting means of each supply permitted by 225.30?

    <p>Not more than six</p> Signup and view all the answers

    According to the text, what type of disconnecting means is required for a feeder or branch circuit?

    <p>Circuit breaker, molded case switch, general-use switch, snap switch, or other approved means</p> Signup and view all the answers

    According to the text, how should the disconnects permitted in 225.33 be grouped?

    <p>They should be marked to indicate the load served</p> Signup and view all the answers

    According to the text, where should the supply disconnecting means be accessible in a multiple-occupancy building?

    <p>Accessible to each occupant</p> Signup and view all the answers

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