IEC YEAR 2 FINAL EXAM 2024-2025, Exams of Nursing

Download IEC YEAR 2 FINAL EXAM 2024-2025 and more Exams Nursing in PDF only on Docsity! 1 | P a g e IEC YEAR 2 FINAL EXAM 2024-2025 WITH ACTUAL CORRECT QUESTIONS AND VERIFIED DETAILED ANSWERS |FREQUENTLY TESTED QUESTIONS AND SOLUTIONS |ALREADY GRADED A+|NEWEST|GUARANTEED PASS|LATEST UPDATE Where installed in conduit, the following colors of insulation or marking are permitted to identify "hot" phase conductors. black, red, blue, brown, orange, yellow, pink, black, and blue You are to install a 20-amp multiwire branch circuit that is fed from the breaker(s) in spaces 2 & 4 in the panelboard shown in Figure 128.182. The circuits supply receptacles in the living room in a house. The breakers can be ___. two 1-pole AFCI breakers with handle ties or one 2-pole AFCI breaker For a 277/480-V, 3-ph, 4-W wiring system, the NEC® permits the insulation for any of the ungrounded conductors to be ___ in color. orange b.black c.brown d.purple any of these (correct) A residential kitchen plan view is shown in Figure 201.62. Which receptacles are required by the NEC® to be GFCI protected? all except 2, 3, 4, 5 & 7 2 | P a g e Harmonic currents occur when ___ loads are connected to the circuit. nonlinear All conductors in a multiwire branch circuit shall originate from the same ___. panelboard What is the maximum allowable voltage between conductors on a branch circuit supplying lighting fixtures (luminaires) in a residence? 120 volts What is the minimum number of 20-ampere branch circuits for small appliances required in a residence? 2 Branch circuits that serve a ___ are required to be rated at 20 amperes where installed in a house. a.bathroom b.kitchen c.laundry room d.all of the above (correct) Branch circuits are rated according to ___. the ampere rating of the overcurrent device Refer to the Article 100 definition for continuous load in the NEC®. According to 210.19(A) the branch- circuit conductors for a continuous load shall be sized at not less than ___ of the current drawn by the load. 125% The smallest permissible wire size for branch circuit conductors supplying other than cooking appliances is ___ AWG according to the NEC®. 14 When several receptacles are connected to a 20-ampere branch circuit, these receptacles are required to be rated ___. 15 or 20 amperes A ___-amp circuit breaker is the largest that can be installed on a 12 AWG copper circuit conductor. The circuit is connected to several receptacles. 5 | P a g e A receptacle under the kitchen counter of a dwelling is used to supply power to a dishwasher. This receptacle is ___ to be connected to one of the two required small-appliance branch circuits. not permitted The plan view of the atrium (foyer) in a large home is shown at the right. The fewest number of convenience receptacles that can be installed per the NEC® is ___. 2 Although not enforceable, a feeder conductor should be sized so that the maximum total voltage drop on both feeders does not exceed ___% to provide reasonable efficiency of operation. 5 When calculating the size of a service, the dryer shall either be ___ volt-amperes or the nameplate rating, whichever is greater. 5,000 Overhead conductors for festoon lighting shall be supported by messenger wire in spans exceeding ___ feet. 40 For a one-family dwelling, the service disconnecting means shall have a rating of not less than ___ amperes, 3-wire. 100 Examples of common calculations can be found ___. in Annex D Each 480-volt, three-phase, wye-connected feeder disconnect with a minimum rating of ___ amperes is required to be ground-fault protected. 1000 A 240/120-V three-wire feeder is to be installed underground from a dwelling unit to a detached garage on the same property. The feeder will be fed from a 90-amp circuit breaker in the dwelling unit panelboard. The feeder will be installed in rigid PVC conduit to the garage. Which of the following best describes Code requirements for installation of this feeder? It must have an equipment grounding conductor. 6 | P a g e The minimum feeder-circuit conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity equal to or greater than the noncontinuous load plus ___ percent of the continuous load. 125 Where installed in a metal raceway, all feeder conductors sharing a common neutral conductor shall be ___. enclosed within the same raceway Ground-fault protection is required for a feeder disconnect if ___. a.the feeder is rated 1,000 amperes or more b.it is a solidly grounded wye system c.the system voltage is 480Y/277 volts d.all of these Feedback all of these Article 210 applies to branch circuits, but branch-circuit calculations for the purpose of determining the size of a service or feeder are covered in ___. Article 220 What Article of the NEC® covers the volt-ampere rating of multioutlet assemblies? 220 The NEC® allows ___ receptacle outlets to be connected on a 120-volt residential lighting or small- appliance branch circuit. an unspecified number of The minimum demand for an electric clothes dryer in a residential load calculation is ___ watts. 5,000 For purposes of calculating a residential service, the general-purpose lighting load is calculated at ___ per square foot of area. 3 volt-amperes Loads, such as heating and air conditioning, that do not operate at the same time are said to be noncoincident loads. While separate circuits must be designed to serve each load, when calculating service load only the ___ of two noncoincident loads needs to be included. larger 7 | P a g e The small-appliance and laundry loads ___ be permitted to be included with the general lighting load and subjected to the demand factors provided in NEC® Table 220.42. shall Using the standard calculation, the demand load for household electric ranges rated in excess of ___ kW is computed per NEC® Table 220.55. 1 3/4 Using the optional calculation method, four or more separately-controlled electric space-heating units are calculated at ___% of their nameplate ratings. 40 Per 220.43(B) in the NEC®, ___ VA must be allocated for the lighting track when determining the calculated load on the service where a 12′ length of lighting track is installed in the conference room in an office building. 900 Loads computed for dwelling unit ___ circuits shall not be permitted to be included with the general lighting load and subjected to the demand factors permitted in Table 220.42 for the general lighting load. appliance For a feeder supplying household cooking equipment and electric clothes dryers, the maximum unbalanced load on the neutral conductor shall be considered as ___ of the load on the ungrounded conductors. 70% A unit load of not less than ___ volt-amperes per square foot shall be included for storage spaces in other than dwellings. 1/4 The NEC® requires the ampacity of a feeder shall be equal to, or greater than ___. the calculated load after demand factors have been applied When calculating the service-entrance conductors for a farm service, the second-largest load of the total load, shall be computed at ___%. 75 When calculating loads to determine the size of a 120/240-volt 1Ø, 3-wire service, the lighting load in amps is calculated by ___ the lighting load in volt-amps by 240 volts. dividing 10 | P a g e The point of attachment of the service-drop conductors to a building must not be less than ___ feet above finish grade. 10 Which of the following is not a standard circuit breaker size? 75 Fixture wire on a 30-amp branch circuit is permitted to be ___. #14 AWG and smaller Type 3 surge protective devices are permitted to be installed ___. in a sub panel 100 feet away from the main distribution panel A conduit contains four dedicated circuits run from a single-phase panel. The circuits are controlled by breakers 1, 3, 5 and 7. How many equipment grounding conductors should be installed in the conduit? One. Based on the overcurrent protective device of the largest circuit in the conduit. Which of the following conduits is not permitted to be used to protect a grounding electrode conductor from physical damage? Schedule 40 PVC Fittings and connectors shall be used only with the specific wiring methods for which they are ___. designed and listed Which of the following conductor arrangements is permitted by the NEC®? a or b only Where installed through wooden studs as shown above in Figure 207.9, which of the installations is permitted by the NEC®? II and III only 11 | P a g e Under which conditions, listed below, does the NEC® permit one conduit to be supported from another as shown above in Figure 207.11? Both conduits contain current-carrying conductors. Where the upper wiring method is EMT and contains circuit conductors to a heating unit and the lower wiring method is Class 2 thermostat cable for the heating unit. Which of the drawings, shown above in Figure 207.12, fails to satisfy the NEC® requirements for conductor length in boxes? II and III only In vertical conduit runs, such as up through a high-rise building, conductors made of aluminum have support requirements that are ___ than for copper conductors. farther apart To avoid heating problems due to induction, the Code generally prohibits installing a single conductor of an alternating-current (ac) system in a metallic raceway. Which of the following single conductors of an ac system is permitted to be installed by itself in a metallic raceway? grounding electrode conductor A metal box or terminal fitting having separately bushed holes for each conductor shall be used whenever change is made from conduit to ___. knob and tube wiring All metal raceways, cable armor, fittings, cabinets, and other metal enclosures for conductors must be ___ joined together to form a continuous electrical conductor. metallically When connections are made in the white wire to receptacles in a multiwire branch circuit, they are required to be ___. made with a pigtail to the silver terminal 12 | P a g e A service lateral is to be installed as direct-buried cable in the bottom of a trench that is 42 inches below finish grade. The trench is to be filled with dirt only. A warning ribbon is required to be installed in the trench at a maximum depth of ___ inches below finish grade. 30 Refer to Figure 207.14. The wiring method is Type USE cable. The minimum distance permitted at Point B is ___ inches. 24 IMC is the wiring method installed beneath the grassy area shown above in Figure 207.15. The minimum dimension permitted for Y is ___ inches. 6 Refer to Figure 207.19, shown above, where luminaires have been installed along a driveway to a single- family ranch home. Type UF cable is the wiring method installed between the luminaires and along the side of the drive. The minimum dimension permitted for Y along the side of the driveway is ___ inches. 24 Conductor sizes are given in AWG or ___. circular mils What is the insulation temperature rating of type THWN wire in a wet location? 75°C XHHW 500 kcmil conductors have an insulation that is ___ mm thick. 1.65 15 | P a g e Chapter 9, Table 8 Which 2 AWG conductor has a lower resistance? copper According to the NEC® an 8 AWG bare stranded copper conductor has a cross-sectional area of ___ square inches. .017 The circular mil area of a 12 AWG conductor is ___. 6530 Except where specifically referenced elsewhere in the Code, Article 312 does not apply to equipment operating at over ___volts. 1000 Where two internal cable clamps are present in a box, a ___ conductor volume allowance will be counted towards the box fill calculation, based on the largest conductor in the box. single How many 12 AWG conductors are permitted to be put in a 4 11/16" × 1 1/2" square box? 9 For straight pulls of 2 AWG conductors through a junction box, the length of the box shall be at least ___ times the size of the largest raceway. 8 According to ___ in the NEC®, unused knockouts and other openings in electrical boxes and cabinets are required to be closed. 312.5(A), 110.12(A), and 314.17(A) Refer to Figure 210.6, shown above. The conductors connected to the terminal lugs are 350 kcmil. The minimum wire bending space required at II is ___ inches. These lugs are NOT removable. 12 Refer to Figure 210.6, shown above. The conductors connected to the terminal lugs are 4/0 AWG. The minimum wire bending space required at II is ___ inches. These lugs are of the lay-in type. 16 | P a g e 6 When making up the branch circuit wires to the breakers in a newly installed panelboard, you found that some of the wires were cut too short. Does the NEC® permit any of these to be spliced with wire nuts so that another piece of wire can be added to be able to reach the breaker or the neutral bar? Yes Cabinets and cutout boxes shall have ___ to accommodate all conductors installed in them without crowding. approved space Enclosures for overcurrent devices in damp or wet locations shall be identified for use in such locations and shall be mounted so there is at least ___ inch airspace between the enclosure and the wall. 1/4 A cabinet or cutout box is constructed of sheet steel, the metal thickness shall not be less than ___ inch uncoated. 8 in. Section ___ of the NEC® permits nonmetallic outlet and device boxes to be installed with nonmetallic sheathed cable. 314.3 In walls or ceilings constructed of ___, it is acceptable to have the front edge of the box set back as much as 1/4 inch from the finish surface. sheetrock In order that the connections inside an outlet box remain accessible, the NEC® permits a surface extension from a flush-mounted device box to be made by installing ___. an extension ring -- shown here → -- with EMT connected to any knockout Calculating and providing the proper volume of a box is not always enough. Section ___ of the NEC® states outlet and device boxes shall be deep enough so that conductors will not be damaged when installing wiring devices or equipment. 314.24 RMC is the wiring method used for the illustration shown below. The conduits are threaded wrenchtight into the entries in the bottom of the "bell" box. No additional support is required for this installation 17 | P a g e (the earth can support the conduits) if the conduit length from the finish surface (dirt here) to the box is ___ inches or less. 18 Does the NEC® permit the installation shown above at X in Figure 208.1? The box is supported only by the conduits. The distance from the top of the head track to the bottom of the 4-SQ box is 2 inches. Both conduits are EMT and are attached to the box with steel compression connectors (not visible in drawing). No A wall-mounted luminaire, such as a sconce, that weighs 4 pounds is permitted to be mounted to and supported by a ___. switch box, a 4″ Sq box with a single-gang plaster ring, or a 4/0 box ___ boxes shall not be used where conduits or connectors requiring the use of locknuts or bushings are to be connected to the side of the box. Round Nonmetallic boxes shall be suitable for the lowest ___ conductor entering the box. temperature-rated Non combustible surfaces that are broken or incomplete shall be repaired so there will be no gaps or open spaces greater than ___ inch at the edge of the fitting or box. 1/8 In completed installations, each outlet box shall have a ___. cover Electrical junction boxes installed in walls and ceilings shall be ___. accessible 20 | P a g e In no case shall conductors in a cablebus be smaller than ___ AWG. 1/0 PVC shall not be permitted where subject to ambient temperature in excess of ___ degrees Farenheit unless listed otherwise. 122 Mineral-insulated, metal-sheathed cable shall be supported and secured at intervals not exceeding ___. 6 feet When installing more than two conductors in a 50 foot run of 3 inch intermediate metal conduit, the maximum area that can be filled with conductors is ___ square inches. 3.169 Where one or more complete paragraphs from the previous edition of the NEC® have been deleted in the current edition, the deletion is identified by ___ between the remaining paragraphs. a bullet ( • ) The purpose of the NEC® is the practical safeguarding of ___ from hazards arising from the use of electricity. persons and property Which of the following installations ARE covered by the NEC®? a. Bolivar ferry boats b.Sprint towers used for cell-phone signal transmission c.Continental Airlines jets such as 767s d.Reliant/HL&P power lines and equipment located in property easements along streets e.none of the above Is the conduit between the street lighting poles covered by the NEC®? The street lighting and conduit were installed in the utility easement as shown in the drawing at the right and is under the control of the utility company. No Which chapters in the NEC® apply generally unless modified by latter chapters? Chapters 1 through 4 The authority having jurisdiction has the responsibility ___. for enforcing the NEC, approving equipment installations, and granting special permission Which of the statements below is an example of mandatory language used in the NEC®? Terminals for more than one conductor and terminals used to connect aluminum shall be so identified 21 | P a g e Informational Notes (I-Notes ) in the National Electrical Code® are ___. explanatory information (not mandatory) Compliance with the provisions of the Code will result in ___. freedom from hazard The Code ___. is not intended as a design specification, is not intended as an instruction manual for untrained persons, and is not necessarily efficient The Code rules and provisions are enforced by ___. government bodies exercising legal jurisdiction over electrical installations What is the point on a wiring system called that takes current to supply utilization equipment? Outlet A unit of an electrical system, other than a conductor, that carries or controls electric energy as its principal function is referred to as a(n) ___. device The definition of a branch circuit is ___. the circuit conductors between the final overcurrent device protecting the circuit and the outlet(s) Nominal voltage includes a range of actual circuit voltages that are ___ the nominal voltage. slightly above and slightly below The NEC® considers an installation inside a building to be a ___ location. dry The neutral conductor of a 120-volt circuit is referred to as the ___ conductor in the NEC®. grounded The "hot" conductor of a circuit is referred to as the ___ conductor in the NEC®. ungrounded A(n) ___ is a box that contains branch circuit conductors that are connected to a luminaire. Lighting outlet The ampacity of an insulated conductor is ___. the maximum amount of current it can carry continuously without damage to the insulation In Figure 210.8 the busbars in Panel I are ___ conductors. 22 | P a g e feeder Refer to Figure 210.18. The grounded conductor between the two panels carries current during ___. normal operation or a short circuit Examples of raceways would include ___. a.EMT b.Schedule 40 PVC c.LFMC d.Wiremold® wall mold e.all of these (correct) A(n) ___ is an assembly of one or more enclosed sections having a common power bus and principally containing motor control units. motor control center A(n) ___ is a device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply. disconnecting means When overcurrent devices are selectively coordinated and a fault occurs somewhere on a branch circuit, what should happen? the branch circuit OCPD that is nearest the fault should open When a piece of equipment is connected to the earth, it meets the definition for ___. grounded The ___ connects the equipment grounding conductors to the grounded (neutral) conductors. main bonding jumper 25 | P a g e For the 120/208-volt panelboard shown in Figure 201.18, the minimum width of the working space directly in front of the panelboard is ___. 34 inches Refer to Figure 201.20. The tops of both panel cans are at the same height above the floor. The bottom of the 277/480-volt panel is at 38″ AFF. The ceiling height can be no less than ___ AFF. 7′-2″ A 1200-A fused safety switch is installed in a room with two personnel doors. These doors are required to ___. I. be equipped with panic hardware II. open in the direction of egress from the room III. open in the direction of entrance to the room I & II only What is an acceptable color for the grounded conductor? White The Code recommends a voltage drop no greater than ___ percent for feeders and no greater than ___ percent total for feeders and branch circuits together. 5 The white conductor contained in a 12/2 with ground MC cable can be marked with purple tape where visible or accessible and used for a traveler from a 3-way switch. True 26 | P a g e Where contained in a cable, the Code reference that states when a conductor with white insulation may be used as an ungrounded circuit conductor is in Section ___. 200.7(C) Where the premises wiring system has branch circuits supplied from more than one nominal voltage system, the means of identification of each system phase conductor, wherever accessible, may be by ___. I. tagging, or other equally effective means II. marking tape III. separate color coding any of the above The grounded conductor of a branch circuit that is 6 AWG or smaller shall be ___. white or gray in color A continuous white or natural gray covering on a conductor shall be used only for the ___ conductor. grounded What is the maximum allowable voltage between conductors on a branch circuit supplying lighting fixtures (luminaires) in a residence? 120 volts No grounded interior wiring shall be electrically connected to a supply system unless the supply system contains a corresponding conductor which is ___. grounded The disconnecting means for a multiwire branch circuit shall open all ___ at the point of origin. ungrounded The nominal voltage of branch circuit conductors in a single-family dwelling shall not exceed ___ volts between conductors. 120 In dwelling units, GFCI protection is required in ___. bathrooms The requirements for the minimum number of branch circuits in a dwelling is found in ___. 210.11 Conductors supplying more than one receptacle for cord-and-plug connected portable loads shall have an ampacity of not less than ___. the branch circuit rating 27 | P a g e A single receptacle installed on a 20-ampere 120-volt circuit shall have an ampere rating of ___. 20 A duplex receptacle installed on a 20-ampere branch circuit shall have a minimum ampere rating of ___. 15 In a single-family dwelling the receptacles shall be installed so that no point measured along the floorline is more than ___ft. to the nearest outlet. 6 In dwelling units, receptacles supplying countertops in the dining room shall be installed so that no point along the wall is more than ___ inches to the nearest receptacle. 24 Although a residential basement is unfinished, the homeowner wants several receptacles to be installed. These receptacles are required to be ___. GFCI protected Refer to Figure 108.014. Where this kitchen is in a house, which receptacles are required to be GFCI protected? 2, 4, 11, 6, 7, 8 & 9 only Guest suites of hotels with permanent cooking provisions shall be required to have AFCI protection for the bedrooms according to ___ in the NEC®. 210.12(C) A receptacle is to be installed outside on the exterior wall of a doctor's office building. This receptacle ___ required to be GFCI protected. is Are lighting fixtures in residential bedroom areas required to have AFCI protection? Yes AFCI protection ___ when a 10-foot branch circuit extension is added to a dwelling family room per the NEC®. is required 30 | P a g e In a 60 Hz circuit, containing a 1.3 mh inductor, the inductive reactance is ___ ohms. .49 ___ is the measure of a circuit's ability to store an electrical charge. Capacitance A sine wave will hit its peak value ___ time(s) during each cycle. 2 Where a 2/0 AWG THHN/THWN copper is connected to a breaker with 75° terminations, its ampacity is limited to ______ amps. 175 Refer to Figure 205.8, shown above. Where not subject to physical abuse, the smallest permitted GEC to the ground rod from Panel LC is ___ AWG. Panel LC has a 400 amp main breaker and is supplied power by the transformer with a set of 600 kcmil conductors. 6 Stainless steel ground rod electrodes ___. I. shall be at least 5/ 8 inch in diameter II. shall be at least 10 feet in length I only AC cable is the wiring method to be used above in Figure 208.3. The length of the AC cable between luminaires is 10 feet. The maximum distance permitted between support #7 and support #8 is ___ feet. 4 1/ 2 The depth ( d) of the 24" x 24" box, shown above in Figure 207.13, is 10 inches. Measured from the point in the box where the conductors emerge from the conduit, the minimum length of the conductors is ___ inches. 6 Statement(s) ___, shown below, is (are) true. I. efficiency = output power ÷ input power II. output power = input power - losses both I & 2 The smallest standard size metal box that can be used for the following is a ___. All connectors are on the exterior. one- 14-2 w/ ground NM cable two- 14 AWG conductors to be connected to the NM cable with wire nuts one- 20 amp 240 volt duplex receptacle (single yoke) 31 | P a g e two- 12 AWG conductors to be connected to the receptacle one- 12 AWG equipment grounding conductor 3¾ x 2 x 3½ masonry box The panel, shown above in Figure 207.6, is 120/240-volt, 1Ø, 3-wire. The load has a rating of 32.4 KW at 240 volts. Each ungrounded conductor will carry ___ amps. 135 A three-phase, 240-volt feeder is going to supply power to one 5 hp 3Ø motor, three 2 hp 3Ø motors, and two 1 hp 3Ø motors. The minimum size conductors permitted for this feeder are ___ AWG. 8 The vertical bathtub zone in which luminaires are not permitted is ___' from the bathtub rim. 8 Motor Nameplate Information: 208-230/460-V 3Ø 5 hp Supply: 3-pole breaker in a 120/208-V, 3-ph, 4-W panel Minimum size circuit conductors are ___ AWG. 12 Refer to Figure 221.101 (above). Drawing ___ (below) shows the transformer correctly connected. C) Where (snap) switches are installed in multigang boxes without permanent barriers (partitions) the maximum voltage between adjacent switches is ___ volts. 300 A 3-phase load draws 37.3 amps and is operating at 208 volts. This load is using ___ KVA of power. 13.438 Three THHN/THWN copper circuit conductors are connected to a 3-pole breaker in a 480/277-volt, 3Ø, 4-wire panelboard. The circuit serves a load that draws 11.9 amps. The distance between the panel and the load is 176 feet. The smallest conductors you can install to the load are ___ AWG. The specifications limit the voltage drop to 2.1%. Use K = 10.86 to solve this problem. 14 The smallest copper service-drop conductors that can be installed for a service are ___. 8 Refer to Figure 221.201. The transformer bank has a ___-connected primary ("H" leads). delta 32 | P a g e Figure 207.3 Nameplate Information: Toaster - 9.2 A @ 110 V Television - 450 W @ 130 V Refer to the wiring diagram shown above in Figure 207.3. What will be the voltage applied (or dropped across) the toaster when the neutral is opened? Select the closest answer. 58 What is the full load current of a 230v, 3ph, 30HP squirrel cage motor? 80 The calculated minimum width (left-to-right) of the pull box shown in Figure 208.53 is ___ inches. Select the larger dimension required: straight pull dimension versus angle pull dimension. 37 Refer to the motor nameplate shown in Figure 230.109. The smallest branch circuit conductors that can be installed between the 2-pole circuit breaker in the 120/240-volt, 3Ø, 4-wire panelboard and the motor are ___ AWG. 10 Motor Nameplate Information: 115/230-V 1Ø 3 hp Supply: 1-pole breaker in a 120/240-V, 1-ph, 3-W panel The maximum size DETD fuses permitted are ___ A. 60 The ampacity of conductors from the generator to the first distribution device(s) containing overcurrent protection shall not be less than ___ percent of the nameplate current rating of the generator. 115 Motor controllers must be marked with ___. I. maximum rated voltage II. maximum hp or current rating both I & II The maximum cross-sectional area that can be occupied by conductor in a 40-foot run of conduit is 53% where the conduit contains ___ conductor(s). 1 A transformer vault is located in the basement of a high-rise building. Where the vault is not protected by an automatic fire suppression system, the minimum concrete floor thickness is ___ inch(es). 4 Refer to Figure 219.102. Each circuit conductor feeding the load connected to Circuit LB-10,12,14 will carry ___ amps. 35 | P a g e Refer to Figure 207.8, shown above. The conductors from Conduit X are permitted to occupy the junction box with the conductors from Conduit Z. True A steel plate is required to protect ___ where it is installed through wooden framing members. A 1? inch clearance from the edge of the framing member can NOT be maintained I. EMT II. Schedule 40 PVC III. RMC neither I nor II nor III Bushings have been installed on all the conduits entering the box shown above in Figure 207.10. Where Conduit X contains 4 AWG, Conduit Y contains 2/0 AWG, and Conduit Z contains 1 AWG conductors, the NEC ® requires ___ to have a bushing. I. Conduit X II. Conduit Y III. Conduit Z I, II, & III What is the maximum size branch-circuit OCPD permitted to serve a single load that is connected with 4 AWG THHN/THWN wire? The branch-circuit OCPD is a circuit breaker that is rated for 75°C. The connected load is NOT continuous and will draw 83 amps. 90 In an AC circuit containing only inductance and/or capacitance, the opposition to current flow is called ___. reactance In an AC circuit containing resistance plus inductance, or resistance plus capacitance, or resistance plus inductance and capacitance, the opposition to current flow is called ___. impedance Inductive reactance is measured in ___. ohms The smallest size copper wire permitted to be used as a main bonding jumper in a 200-A main breaker panelboard is ___ AWG. The panel is fed from a transformer with one set of 3/0 AWG wire. 4 Refer to Figure 205.4. A 120/240-volt, 1-ph, 3-wire service is to be run to serve 125-A, main breaker Panel B. As shown, one conduit will be installed for the service. The conduit will contain two 1 AWG conductors for the ungrounded conductors. Most of the loads are 240-volt, 1Ø phase without neutrals. The smallest MBJ that can be installed in Panel B is a ___ AWG. 36 | P a g e 6 As shown in Figure 205.5, one conduit will be installed for the service. The conduit will contain three 3/0 AWG conductors for the ungrounded conductors and one 3/0 AWG conductor for the grounded conductor. The smallest MBJ that can be installed in the panel is a ___ AWG. 4 A transformer supplies power to a 240-volt, 3Ø, non-continuous 32.286 KVA load. The smallest secondary circuit conductors that can be used are ___ AWG. 4 A transformer is installed to serve a 240-volt, three-phase, 69 KW load. The smallest permitted secondary conductors are ___. 2/0 AWG The primary of a 112.5 KVA transformer is 480-volt delta. The secondary is 240-volt delta and is delivering 100 amps to a 3Ø load. Given these conditions, ___ amps of current are flowing through each primary winding. 29 The exact Code reference that requires electrical equipment to be securely fastened to the surface on which it is mounted is ___. 110.13(A) Where circuit breaker terminals or safety switch lugs are marked on the equipment (or included with installation instructions) with a tightening torque by the manufacturer, this torque is required to be applied to the connections. True The NEC ® permits the attachment cord and plug that is attached to an air compressor to be used as the disconnecting means. How does Section 110.22 require that this disconnecting means be identified? Its purpose is obvious and not required to be marked. The minimum working clearance at Point X in Figure 201.15 is ___ feet. The panel is 277/480-volt, 3Ø, 4W. 3 1/ 2 A 3/ 4-inch PVC conduit is to be run underground below an area adjacent to a house where a 6" thick driveway will be poured on top of the dirt surface after the trench is backfilled. The conduit will contain GFCI protected 15-Amp circuit conductors feeding a post luminaire in the front yard. The minimum depth the conduit must be below the present dirt surface level (future driveway) is ___ inches. 6 37 | P a g e Refer to Figure 207.14. The wiring method is RMC. The minimum distance permitted beneath the sidewalk at Point A (from the bottom of the 4" thick sidewalk to the top of the conduit) is ___ inches. 0 Refer to Figure 207.14. The wiring method is PVC. The minimum distance permitted at Point C (below the brick building with a 6" concrete slab) is ___ inches. 0 Refer to Figure 207.14. The wiring method is Type USE cable. The minimum distance permitted at Point D is ___ inches. 18 The output rating of generators is given on the nameplate in ___. I. KVA II. KW either I or II In generator set exhaust systems, excess horizontal and vertical exhaust piping distances produce increased back pressure and may require ___. any of these Which of the illustrations shown in Figure 210.1 fails to satisfy the Code requirements of 240.22(1)? I & III only The neutral is bonded to the frame and connected to a ground rod near a 3Ø, 4-wire 120/208-volt optional standby generator. The transfer switch supplying power to a building system from this generator is required to have ___ poles. 4 Generator overcurrent protection is covered in NEC ® Section ___. 445.12 Transfer equipment for emergency systems shall be designed and installed to prevent the inadvertent interconnection of ___ sources of supply in any operation of the transfer equipment. normal and emergency ___ power is power that passes through reactive components, which do not consume energy, and returns to the source. Reactive Apparent power is measured in ___. volt-amps 40 | P a g e Refer to the information shown in Figure 230.230. The smallest, non-fused, Square D safety switch (standard size General Duty) that can be installed for this motor is a ___ A. 60 Refer to the information shown in Figure 230.231. To be able to contain time-delay fuses, the smallest, Square D, heavy duty safety switch has a ___ amp rating. 200 When a 3Ø, 4-W supply system delivers 120/208 volts, the system is ___ connected. wye When a 3Ø, 4-W supply system delivers 120/240 volts, the system is ___ connected. delta When a 3Ø, 3-W supply system delivers 480 volts, the system is ___ connected. delta If three single-phase, 37.5 KVA transformers are connected together to form a three-phase delta bank, what will be the total KVA rating? 112 and 1/2 Anex _____ in the NEC contains examples of load calculations for dwellings. D Which of the installations listed below would be a wet location? -a receptacle installed on the exterior wall of a building - a run of PVC conduit installed on a fishing pier -a luminaire installed on a parking lot pole all of these Which of the following is an example of a bare conductor? - a 12 awg THHN copper wire - the bare ground wire contained within romex (NM cable) sheathing -the bare aluminum wire twisted with triplex the bare aluminum wire twisted with triplex Which of the following statements is TRUE for an individual (or dedicated) branch circuit that is run in a conduit with other circuits? it can share a neutral with another circuit Equipment designed to open circuits under ____ shall have an interrupting rating not less than the nominal circuit voltage and the current that is available at the line side of the equipment. - short circuit 41 | P a g e -overload -ground fault all of these The NEC permits the insulation for an ungrounded conductor to be _____ in color. - orange -black -brown -yellow any of these Which of the following locations requires that a three-way switch be installed at the lower landing and another three-way switch be installed at the upper landing to control the stair way lighting between the 1st and 2nd floors? a townhome A 175- amp breaker protects a feeder that originates in a 277/480-volt, 3-ph, 4 wire service panel in an office building. Which of the following conductors is the smallest size permitted for the feeder ? 2/0 A 200-amp breaker protects a feeder that originates in a 120/240 volt, 3 ph, 4 wire service panel in a movie theatre. Which of the following THHN/THWN conductors is the smallest size permitted for the feeder ? 3/0 The maximum number of 3-pole circuit breakers used as service disconnects permitted in a 3 phase panelboard is ______. 6 Which of the following are characteristics of THHN/THWN insulation? - heat-resistant - a nylon outer covering or some equivalent - flame retardant -moisture-resistant all of these For the purpose of determining the number of current-carrying conductors in a cable or conduit, the neutral _____ counted when the branch circuit is 120/240-volt, 1 phase, 3 wire connected to a 120/240- volt, 3 phase delta, 4 wire panelboard. Each of the two circuits carries 16 amps and serves resistive (linear) loads. is not 42 | P a g e Where a 120/240 volt, 1 phase, 3 wire multiwire branch circuit is connected to a "split-wired" duplex receptacle in a barber shop, the branch-circuit OCPD/disconnect is permitted to be ______ i. two single-pole circuit breakers without handle ties ii. two single-pole circuit breakers with identified handle ties iii. a 2-pole circuit breaker ii or iii only Which of the following is a type of circuit condition? i.short circuit ii. overload i and ii A 20-amp multiwire branch circuit is connected to breakers 1 and 3 in a 120/208 volt 3 phase 4 wire panelboard. _____ if the "hot" from breaker 3 and the neutral are connected to a 2000-watt lighting fixture load. The load will operate normally and the breaker will not trip When ____ touch together this is a short circuit. -i. two ungrounded circuit conductors - ii.an ungrounded and a grounded circuit conductor - iii. an ungrounded circuit conductor and the metal conduit. i or ii only You are going to pull in three dedicated (individual) branch circuits into one conduit. Each circuit supplies power to a 120-volt load. The ungrounded conductors will be connected to breakers 2,4 and 6 in a 120/240 volt single phase 3- wire panel board. Per the NEC, the fewest number of neutral conductors you can install for the branch circuit is _______. 2 In a run of conduit, when couplings and connectors are loose this will ____ the amount of time required for a circuit breaker to open when an overload occurs. have no effect on Your only available grounding electrode is the metal underground water pipe from the water utility. You are required by the NEC to have one other grounding electrode for your service. Which of the following driven electrodes could you use ? 10 ft of trade size 1 rigid metal conduit Your only available grounding electroe is the metal underground water pipe from the water utility. You are required by the NEC to have one other grounding electrode for your service. You could use which of the following driven electrodes? -i. 10 ft trade size 1 rigid metal conduit -ii. 8' by 1/2 inch copper-clad ground rod 45 | P a g e An electric-discharge luminaire utilizes a ____ for the operation of the lamp. ballast ______ shall not support luminairs weighing over 6 lb. lampholder The smallest circuit breaker that can be installed in a panel is ____ amp. The circuit supplies power to a 240-volt, single-phase, 5.8 KW, 50-gallon water heater. 30 A 100-gallon water heater is to be installed to supply hot water to the restrooms in an office building. The water heater is rated for 9.8 KW at 240 volts 1- phase. The minimum size THHN/THWN copper wire that can be installed between the required disconnect switch and the water heater is _____ AWG. 6 A unit switch is the ON/OFF switch on an appliance that disconnects all ____ conductors. ungrounded A magnetic field is made up of invisible lines of force called ______ magnetic flux Where operating in the United States, AC voltage reaches a negative peak _____ times during one second. 60 Which of the conversion formulas listed below is correct? RMS= Peak x .707 RMS= Peak x 1.414 RMS= Peak x .707 Which of the conversion formulas listed below is correct? Peak = RMS x 1.414 Peak= RMS/1.414 Peak= RMS x 1.414 The unit of measure for capacitance is ______. Farads When a resistive AC circuit also contains inductance and/or capacitance, the total opposition to current flow is called ______. impedance In a 60 Hz circuit, containing a 12 uf capacitor, the capacitive reactance is ____ ohms. 46 | P a g e 221.04 In a circuit with 25 ohms resistance and 50 ohms capacitive reactance, the impedance is ______ ohms. 55.9017 At a recreational vehicle park, electrical service feeders shall be calculated on basis of not less than 600 volt-amperes per site when equipped with _________. 20a supply facilties with only one dedicated tent site In an AC circuit the total opposition to current flow is referred to as ______. Impedance (z) True power is measure in ______ watts _______ surrounds the windings in typical "pole-mounted" transformers. oil In reality, transformer efficiency can never be 100% because of ______. -i.eddy-current losses -ii. copper losses both i and ii Transformers power ratings can be in ______. -i. VA -ii. MVA -iii. KVA any of these Most commonly, the supply circuit to a transformer is connected to the leads, terminals, or lugs marked as the _______. primary The principle upon which transormers operate is _____. electromagnetic induction A transformer's primary winding and secondary winding are actually connected together. T/F False A load that uses 6.2 KW of power is using _____ watts. -.62 -. .062 -.620 -.6.2 47 | P a g e none of these Generally transformers have an efficiency of more than 90%. T/F True A transformer has a primary rating of 480 volts and supplies 240 volts to a 7.4 KVA load. The circuit that is connected to the primary originates from a 2-pole circuit breaker in a 277/480 volt 3 phase 4 wire panelboard. The current measure in one of the circuit conductors connected tot he breaker is 15.9 amps. The efficiency of this transformer is _______ % 96.96 ______ in utility transmission lines reduces the power losses in the transmission conductors. increasing the voltage Temperature _____ is the difference in temperature between the transformer windings and the ambient temperature surrounding the transformer. rise 40C = ____ F 104 When a transformer is loaded beyond its rating the effects in the transformer are ______ -i. excessive temperature -ii. deterioration of insulation -iii. coil failure i, ii and iii Dry-type distribution transformers are equipped with _____ to reduce mechanical noise due to vibration. isolation pads A .25KVA transformer has a nameplate rating of 240/480 primary volts 120/240 secondary volts. IF rated voltage is applied to the primary the secondary voltage will be _____ than the nameplate secondary voltage because these small transformers have compensation built into their secondaries. Higher/lower higher You need to change from 240 volts to 480 volts to operate a piece of equipment that will require 25 KVA at 480 volts. You must use a transformer that is built specifically for step-up applications. T/F false A square D transformer with a nameplate rating of 240/480- V primary and 120/240 volt secondary can be connected to a 2-pole breaker in a _______ panelboard and deliver nameplate-rated voltage to a load.