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229 Multiple choice questions

  1. Per NEC 250.116 ground rods should attach to metal fences
  2. Visible and within 50 ft.
  3. The current stays the same cause the doubling is offset by the halving.
  4. Two outside ground wire are needed on a 400 amp.
  5. True
  6. "Authority Having Jurisdiction (AHJ)"
  7. active or live
  8. NEC Section 250.118(5)
  9. NEC 225.18
  10. A grounded conductor is a system or circuit that is intentionally grounded.
  11. False, demand factors of lighting does not apply to this table.
  12. The smallest grounding conductor permitted is 6 awg or larger.
  13. 1. The Builder
    2. Homeowner
    3. Inspector
    4. Boss
  14. 10ft.
  15. 2 ground rods 6 ft apart.
  16. False, Depending on the location and environment, 3ft. may be insufficient clearance. While grouping apparatuses tightly may save space, repair and maneuvering options are limited should a device fail.
  17. NEC 250.114
  18. Is dedicated to the sizes of the grounding conductor
  19. False, run ground wire from panel to copper water pipe then jump the water meter using grounding clamps.
  20. Grounded
  21. Isolated systems are used in healthcare facilities due to explosive gases.
  22. The maximum amount of electrical current a conductor or device can carry before sustaining immediate or progressive deterioration.
  23. NEC Tables Annex C1 and C2 identify both wire sizing and the temperature a wire can handle in amps.
  24. Per NEC 230.10, vegetation is disallowed as a support device.
  25. True
  26. True, Receptacles fed from subpanels must have their equipment grounding bar that is electrically isolated from the neutral bar.
  27. It guards wire against damage.
  28. Per NEC 225.14, separated by 4in.
  29. "The permanent joining of metallic parts to form an electrically conductive path that ensures electrical continuity and the capacity to conduct safely any current likely to be imposed."
  30. A device designed to trip when an overcurrent is detected.
  31. False, Arcing is the phenomenon in which electrons jump across insulators to positive terminals, which can occur through air, paper, rubber, or any other insulator.
  32. 48 in.
  33. 350MCM or 400MCM
  34. 16 in.
  35. Shows in two columns (milimeters and inches), how many wires in trade size you can place in a box.
  36. True, although there are exceptions.
  37. NEC Section 250-126
  38. NEC 310.8
  39. Air, does not conduct electricity.
  40. Covers the sizes of alternating current grounding electrode conductors.
  41. Voltage level, amount of protective clothing, and moisture on skin or outerwear all impact a ground connection.
  42. 2/0 or 4/0
  43. Identified as the "B" leg
  44. 6ft
  45. False, Per NEC 230.24, Service drop connectors shall not be readily accessible.
  46. NEC Article 358 covers EMT.
  47. True, One is required, Two are suggested.
  48. Is a measure of the amount of electric charge passing a point in an electric circuit per unit time.
  49. 120V
  50. Reliable
  51. Electrical installations at permanently installed pools.
  52. False, Protecting a motor and a motor circuit are two very different things
  53. Safety is the most important aspect of an electrician's job.
  54. True, Per NEC 422.35
  55. True
  56. True, motors convert electricity to rotational motion, while generators convert rotary motion to electricity.
  57. For a raceway to be used. Find a value for area larger than the raceway area calculated previously.
  58. The fill of metal boxes appears in NEC Tables 314.6 A and B.
  59. False, Per 360.12, FMT is disallowed from battery storage areas
  60. True, when those water pipes are grounded.
  61. True
  62. True - NEMA is the acronym for National Electrical Manufacturers Association.
  63. 1.Insulated Housings.
    2. Ground prong on plugs.
  64. people and property
  65. Relative to underground service, overhead electrical service is simpler to troubleshoot and repair and is the easier option when running electricity across roadways, waterways, and right-of-ways.
  66. False, The way to ground a transformer in a commercial building is to place a grounding rod outside or beneath the building.
  67. NEC 314.3
  68. True, An attic with a furnace requires a receptacle to honor safety and sound wiring requirements.
  69. Covers clearances on buildings.
  70. True
  71. NEC 320
  72. 1. Listed Pressures Connectors
    2. Terminal Bars
    3. Pressure Connectors Listed As Ground and Bonding Equipment
    4. Exothermic Welding
    5. Machine screw-type fasteners that engage not less than two threads or are screwed with nuts
  73. Green finish
  74. According to the NEC, an outlet is defined as a point in a circuit at which current is taken.
  75. False, NEC 314.4, requires all metallic boxes to be grounded.
  76. Using ohms law, the fuse value would be 10V/2ohms or 5 amperes. However, if the voltage increased slightly and harmlessly, the fuse would blow. Therefore the fuse should be based on the nature of the load.
  77. When only the steel is connected to earth ground.
  78. True, Per NEC 210.11
  79. True (NEC 250.92B)
  80. A grounding conductor is green.
  81. 30amps (10 x 3)
  82. True, Electricians may use rebar as a grounding means.
  83. In DC, electrons flow in one direction only. In AC, electrons "saw" back and forth in the load. AC is easier to manufacture and is most often delivered and used in a residence, business, or factory.
  84. True, Intrinsically safe areas are safe with out enclosure, but enclosure are required for other protections.
  85. Connections
  86. NEC 250.66 provides the sizing of grounding electrode conductors
  87. A Direct burial clamp is needed to properly connect number 4 copper to a ground rod.
  88. A bonding screw is green.
  89. False, Fuses on the load side do not protect the transformer.
  90. 1. Branch circuit in which the initial run is encased in AC up to the first receptacle, which is mounted in a plastic box.
    2. Branch circuit in which the initial run is encased in AC up to the first receptacle, which is mounted in a metal box.
    3. clothes closet measuring more than 10 sq ft.
  91. NEC 220.16 - 220.20 cover appliance calculations.
  92. A bonding jumper should be installed inside or outside raceway within 6ft. of attachment. (NEC 250.118)
  93. Heat, Magnetism, and Light
  94. Although not required by NEC, in general any receptacles below grade, including those in finished basements, should be GFCI protected. Receptacles in dwelling accessory building with floors at or below grade level require GFCI protection. unfinished basements require GFCI-protected receptacles.
  95. Mechanical and Electrical continuity conductors.
  96. NEC Section 250-119 1-14
  97. A 12in. counter requires a receptacle because it holds small appliances.
  98. A gounding system is connected to the ground or to a conductive body that extends the ground connection.
  99. Ground and Arc are two types of electrical faults.
  100. Per NEC 230.40, "Every service drop or lateral shall supply only one set of service entrance conductors."
  101. True
  102. Chapter 9
  103. False, a A/C unit needs only 220 and a ground to complete the circuit.
  104. Ground Rod
  105. Per NEC 450.3, phases must arrange in a particular order: A, B, C, from left to right or from top to bottom as seen from the front.
  106. True, Per NEC 422.31
  107. NEC Article 250
  108. Water, lacks insulation qualities because it conducts electricity. As a result, it is one of the most hazardous substances in an electrical environment.
  109. False, Per NEC 450.4 a OCPD is no needed.
  110. False, Current is fatal to people not Voltage
  111. Although a 15amp breaker is above code, it is preferable when considering expansion.
  112. Receptacles must be installed on a peninsula when the peninsula's long edge is at least 24in. and its short edge is at least 12in.
  113. A mandatory act or condition
  114. inside
  115. To test conduit for proper grounding, check ohms or use 120V receptacle and touch to ground to check for voltage.
  116. True, Per NEC 300.11 hanging a second support when running new over old is acceptable and a common practice.
  117. A grounding conductor is a conductor or circuit of a wiring system to a grounding electrode (ground rod).
  118. To ground a subpanel in the another building, run bare copper wire from subpanel to ground rod inside or outside.
  119. NEC Article 408 covers panel board applications.
  120. NEC 110.23 states that, "Unused current transformers associated with potentially energized circuits shall be short circuited."
  121. True, all equipment must be installed per manufacturer's instructions and specifications, The apparatus is void and violates NEC if this is not done.
  122. According to new codes, ARC fault protection is needed many additional parts of the house.
  123. Per NEC 250.26, The Neutral conductor serves as ground.
  124. Two hots are needed to operate the heater neutral. The timers can serve as ground for tripping mechanism.
  125. Chapter 5
  126. The sizes of copper and aluminum wire, as well as the coating of wire that has fewer than three current carrying wires in a cable or conduit or that is buried in the earth.
  127. Per NEC 220.84, A 21 unit building would be rated at 32% and any occupancy over 62 units rated at 23%
  128. False, via a green wire
  129. High impedance grounding is used for grounding radio towers. NEC 250.20(E)
  130. Per NEC 422.11, The size of the breaker to use.
  131. NEC Article 230
  132. NEC 300.5, provides requirements up to 600V
  133. True
  134. Per NEC 680.90(A), GFCI protection Must reside on whirlpool tubs.
  135. False, grounding conuctors belong on the green screws.
  136. False, unless it is 8ft above the rim of the shower zone and listed for wet environments.
  137. NEC is also know as the NFPA 70
  138. Terms and Definitions
  139. Per NEC 100, Property owners can act as their own "Authority Having Jurisdiction" (AHJ)
  140. According to NEC Article 100, a device that opens and closes a circuit by nonautomatic means automatically closes for a predetermined overcurrent.
  141. Chapter 9, Table 4 outlines trade size of conduit as well as raceway size.
  142. False, No disconnect is required.
  143. Circuit Breaker
  144. False, NEC does not approve tress as service conductors.
  145. False, the smaller the diameter increases resistance to flow.
  146. Electricians can use sheet metal screws for bonding when those screws are green and have hexagonal heads (NEC 250.8), but it is generally considered unwise.
  147. Definitions
  148. To make a proper grounding system using three 200-amp disconnects, use a ground wire of sufficient size to go from panel to panel with a lug, screw, or ground bar, if provided.
  149. First determine whether the application is residential. For residential applications, the NEC provides no guidance. The answer for nonresidential applications is based on box fill. For these applications, most electricians calculate between 1 and 1.5 amperes per receptacle.
  150. The thicker the wire. Gauge was designed to reflect the number of wires that can fit through an opening.
  151. 20ft. of bare copper not smaller than 2 AWG
  152. 6.25amps, 750 watts divided by 120V is 6.25amps
  153. Equipment fastened or connection between metal parts.
  154. True
  155. NEC Articles 342, 344, and 358 outline the installation requirements of RMC, IMC, and EMT.
  156. Per NEC 392.7(B) Bonding of all cable tray sections is required.
  157. 12ft.
  158. Per NEC 225.34, a maximum of six disconnects are allowed per service entrance.
  159. False, The term electricity is defined as the imbalance in the negative charges, or electrons, between two points.
  160. Grounding
  161. True, Per NEC Article 400, only when rated for wet areas.
  162. NEC Article 517
  163. "the current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating"
  164. False, NEC 402.5 defines ampacity requirements for fixture wires.
  165. Resistive, impedance, and skin effect.
  166. True, It is a good idea to exceed the requirements by a foot or two.
  167. Liquid Filled and Dry Versions
  168. Heart fibrillation is the major cause of death from electrical shock. The shock disrupts the normal electrical brain to heart signals.
  169. Per NEC 450.46 only transformers over 100KW require a drain, however installing a drain in case of dielectric spills is good practice.
  170. A receptacle with NEMA 5-20R on it has an amperes rating of 20, will take a NEMA-5-15P or NEMA-5-20P plug, and has a voltage rating of 125.
  171. Breaker Rating determines ampacity, or size, of a circuit.
  172. Deicing systems
  173. Because garage space is not considered livable space, subtract its area from the total living area. The home's livable area 28 x 40 is 1,120ft.
  174. Per NEC 220.13, use 100% of the first 10KW and 50% of the demand above 10KW. In this case, the demand factor would be 10,000 plus half the remaining 10,000 or 15,000W
  175. NEC Article 392
  176. True (NEC 250.92B)
  177. Bonding jumpers
  178. 1. Bonding jumper is sized not less than 12.5% of the largest phase conductor.

    2. Based on the largest ungrounded service conductor.

    3. Based on the largest sum of the service conductors.
  179. False, Per NEC 450.23-26 liquid-filled transformers have different requirements based on the dielectric fluid.
  180. Two hots are needed to operate the stove neutral. The timers and clocks can serve as ground for tripping mechanism.
  181. Smaller its AWG
  182. False, NEC 312.3, disallows recessing panels in flammable walls.
  183. OCPD
  184. Three residential areas that require 20-amp circuits are the kitchen, bathroom, and laundry room.
  185. sledge hammer, hammer drill, and ground rod pounders
  186. True
  187. NEC requires a clearance width of 30in. and a clearance depth of 36in.
  188. In a parallel circuit, each load is connected in a separate path. In a circuit schematic, the branch lines are parallel.
  189. NEC Section 250-118
  190. Annex C of NEC covers conduit and tubing fill for conductors and fixture wire fill.
  191. To locate wire type and size to be installed. Repeat for each conductor, keeping a running total. Derate by 40% to ge the total raceway area.
  192. 15v 120V/8
  193. Damage may occur in the meter and or personal injury.
  194. The National Fire Protection Association (NFPA) sponsors the NEC
  195. NEC Table 250.66
  196. Chapter 3
  197. amperes, named after the French scientist, Andre Marie Ampere
  198. False, ceiling tiles are never appropriate device support.
  199. 3ft.
  200. True, like a refrigerator the appliance should continue running when another component fails, the grounding system must be able to support the service on its own.
  201. Per NEC 402.3, FFH-2 fixture wiring is useable up to 75 degrees C
  202. NEC requires a minimum of 3 watts per residential sq ft. The kitchen may require more for better lighting.
  203. NEC 90.1(C)
  204. Electron
  205. True, Per NEC 422.31
  206. False, A bonding screw is unneeded in a subpanel.
  207. "All circuit conductors between the service equipment, the source of a separately derived system, or other power source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device,"
  208. False, a TVSS is only for protecting against predictable anomalies, and short-duration spikes of high-voltage.
  209. Exothermic welding involves the fusion of metal materials or copper to rebar.
  210. 14 gauge; 2

    12 gauge; 2.25

    10 gauge; 3
  211. Yes, a receptacle is required in close proximity to an air-conditioning unit. At most, it must be 25ft. distant.
  212. Dedicated
  213. 7.5amps, 1,800 watts divided by 240V is 7.5amps
  214. 1. Air-borne Particulate
    2. Sawdust
  215. Each receptacle or switch counts as 2 conductors, and 14 AWG wire conductors require 2 each. Therefore, 2 conductors x 2 = 4 cu. in. Add to this 2 for the yoke and 2 for the ground for a total 0f 8
  216. Given that power equals voltage times resistance, power in this example is 24 watts (2amp x 12V)
  217. Water Pipe, A grounding system designed as a main service ground takes priority over a system that provides grounding alone. While requiring as large a grounding surface area as possible is advantageous, the grounding system must be able to support the service on its own.
  218. The size of the largest conductor determines what size ground wire used on a service.
  219. An isolated grounded reciprocal is a separate ground from a device directly to a panel.
  220. Equipment Bonding Jumpers
  221. NEC Article 386 covers metallic or metal raceway; NEC Article 388 covers PVC pipe.
  222. Marked CO/ALR
  223. False, The negative terminal has a surplus of electrons and the positive terminal has a surplus of protons
  224. An Intrinsically Safe System.
  225. A main bonding jumper and a system bonding jumper.
  226. Per NEC 90.4, 510.2, and various local codes, occupancy is permitted in the event of a code violation as long as the occupancy remains unchanged and no hazardous condition exists.
  227. To ground a subpanel in the same building, run a four-wire system from main panel to subpanel.
  228. 120V
  229. 18ft.