Advanced Lightning

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MrLightning
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246689
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Advanced Lightning
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2013-11-13 09:45:54
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advanced lightning
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  1. NFPA 780 covers traditional lightning protection system installation requirements for which structures?
    • -Ordinary Structures
    • -Miscellaneous structures and special occupancies
    • -Heavy-duty stacks
    • -Watercraft
    • -Structures containing flammable vapors, gases, liquids
  2. What is the purpose of the NFPA 780 standard?
    To provide for the safeguarding of persons and property from hazards arising from exposure to lightning.
  3. What is sideflash?
    An electrical spark, caused by differences of potential, that occurs between conductive metal bodies or between conductive metal bodies and a component of a lightning protection system or ground.   3.3.27
  4. Spark Gap
    Any short air space between two conductors that are electrically insulated from or remotely electrically connected to each other.  3.3.28
  5. What is Zone of Protection?
    The space adjacent to a lightning protection system that is substantially immune to direct lightning flashes.  3.3.39
  6. Class I Solid Air Terminal Diameter

    Copper?

    Aluminum?
    Copper  3/8"

    Aluminum 1/2"
  7. Tubular Air Terminal Diameter

    Copper?

    Aluminum?
    Copper 5/8"

    Aluminum 5/8"

    Class I only!
  8. Class I Main Conductor Size Each Strand

    Copper?

    Aluminum?
    Copper 17 AWG

    Aluminum 14 AWG
  9. Class I Main Conductor Weight

    Copper?

    Aluminum?
    Copper 187 lb/1000'

    Aluminum 95 lb/1000'
  10. What is the AWG size of Class I Copper Cable?
    17 AWG
  11. What is the AWG size of Class II Copper Cable?
    15 AWG
  12. What is the weight per length of copper Class I cable?
    187.5 lbs/ 1000 feet
  13. What is the weight per length of copper Class II cable?
    375 lbs / 1000 feet
  14. What is the AWG size of Class I aluminium cable?
    14 AWG
  15. What is the AWG size of Class II aluminium cable?
    13 AWG
  16. What is the weight per length of aluminum Class I cable?
    95 lbs/1000 feet
  17. What is the weight per length of aluminium Class II cable?
    190 lbs/1000 feet
  18. What is the diameter of a Class I copper solid air terminal?
    3/8 inch
  19. What is the diameter of a Class II copper solid air terminal?
    1/2 inch
  20. What is the diameter of Class I aluminium solid air terminal?
    1/2 inch
  21. What is the diameter of Class II aluminium solid air terminal?
    5/8 inch
  22. What is the diameter of copper and aluminium tubular air terminal?
    5/8 inch

    • AND
    • Copper wall thickness is 0.32 inch
    • Aluminium wall thickness is 0.64 inch
  23. What class can tubular air terminals be used for?
    Class I
  24. What is the coarse and fine thread count of a 1/4" bolt?
    20 and 28
  25. What is the coarse and fine thread count for a 1/2" bolt?
    13 and 20
  26. What is the equation for slope?
    Rise / Run
  27. What year was the Lightning Protection Institute founded in?
    1955
  28. The Lightning Protection Institute promotes what?
    • Education
    • Awareness
    • Safety
  29. What five elements need to be in place provide an effective lightning protection system?
    • Strike termination devices
    • Cable conductors
    • Grounding electrode system
    • Bonding
    • Surge Protection Devices
  30. What do lightning protection component materials need to be?
    • Resistant to corrosion
    • Protected from accelerated deterioration
  31. What is electrically charged around us?
    the atmosphere
  32. What proper resistance is expected of a proper grounding electrode if the soil is of normal restivity?
    less than 50 ohms
  33. Copper components installed with 24 inches of a top of a chimney or vent that emits corrosive gases shall be what?
    protected by lead or tin coating
  34. Aluminum conductor shall not be attached or installed in what three circumstances?
    • alkaline-base paint
    • embedded in concrete/masonry
    • subject to excessive moisture
  35. Connector fitting shall be used at what three splices?
    • End-to-end
    • Tee
    • Y
  36. What amount of lbs shall all fittings be able to withstand in a pull test?
    200 lbs
  37. What is the minimum outside diameter of masonry anchors?
    1/4"
  38. How far above the object shall air terminals extend to protect the object?
    no less than 10"
  39. What is the wind resistance area of an ornament or decoration?
     no greater than 20 square inches
  40. What is the horizontal protected distance formula?
  41. What happens to the zone of protection when the protection is no higher than 25 feet above grade?
    1 to 2
  42. What happens to the zone of protection when the protection is higher than 25 feet but lower than 50 feet?
    1 to 1
  43. How many feet above grade is it required to protect down conductors from mechanical damage?
    6'
  44. How many feet above grade is it required to protect down conductors that are entering into corrosive soil?
    3 feet
  45. What is the minimum diameter and length of ground rods?
    1/2" and 8 ft long
  46. How far shall ground rods extend vertically?
    not less than 10'
  47. What is the separation between any two ground rods?
    at least the sum of the rod lengths
  48. What is the bonding distance formula?
  49. All grounded media and buried metallic conductors that can assist in providing a path for lightning currents in or on a structure shall be interconnected to the system within how many feet of the base of the structure?
    12 feet
  50. What standards does it require that buildings over 60 feet in height require a ground loop?
    LPI 175 and NFPA 780
  51. What does the interconnection of building system ground devices include?
    • Lightning protection
    • Electric service
    • Communications
    • Antenna system grounding
  52. Within how many feet is it required to bond underground metallic piping systems (water, gas, conduits, petroleum) of a structure?
    25 feet
  53. What is the common bonding point if the grounded systems (water, gas, electric, communications) are interconnected at a common accessible point in the structure?
    • A ground bar
    • A section of water pepe OR
    • The metallic structural frame
  54. Metal bodies located outside or inside the structure that contribute to lightning hazards shall be what?
    interconnected with the lightning protection system
  55. What is potential equalization?
    the bonding together of grounded systems at different building height intervals to eliminate side flash
  56. Structures exceeding 60 feet in height need what three potential equalizations?
    • Ground-Level
    • Roof-Level (12 feet)
    • Intermediate-Level
  57. Structures up to 60 feet in heigh need what two potential equalizations?
    • Ground-level
    • Roof-level  (7 feet)
  58. How small can ground loop conductors be?
    no smaller than main lightning conductor
  59. Should SPDs be grounded through a lightning protection down conductor?
    No
  60. Where are SPDs installed?
    All power service entrances
  61. What dp SPDs need to be in compliance with?
    UL 1449 Edition 3
  62. What is the nominal discharge rating of SPDs for branch panels or subpanels?  AND is for signal data or communication systems?
  63. What is the nominal discharge rating of SPDS for supplementary protection?
  64. What is the nominal discharge rating of SPDS for service entrances?
  65. Gable
  66. Broken Gable
  67. Gambrel
  68. Hip
  69. What shall surge protection be provided for?
    • Conductive signal
    • data
    • communication lines
  70. What three things should be considered when selecting SPDs?
    • frequency
    • bandwidth
    • voltage
  71. What shall SPDs for data and signal line protection have?
    common mode protection
  72. When installing strike termination devices on structural steel what are the intervals?
    air terminals are connected to the metal framework at intervals not exceeding an average distance of 100 feet and are to be as widely spaced as possible.
  73. When fastening conductor to a metallic column what is the diameter and how many threads need to be fully engaged?
    • no less than 1/2 inch in diameter
    • at least 5 threads fully engaged
  74. When installing ground electrodes that are connected to metallic columns, how are they installed?
    around the perimeter of the structure at intervals averaging not more than 60 feet apart.
  75. What can be used for protecting down conductors from mechanical damage?
    • wood
    • plastic (PVC)
    • metal laid over the conductor
  76. When does the zone of protection arc change to 100 feet?
    • Flammable materials
    • Ammunition
    • Masts (2 or more)
  77. How far away do silos and storage tanks have to be to be classified as standing alone?
    6 feet
  78. What determines an adjacent storage structure?
    if it is 6 feet or less away from the main building but not attached
  79. How tall is a heavy duty stack and what is the single cross-sectional flue area?
    • more than 75 feet
    • flue area exceeds 500 square inches
  80. What class materials should heavy duty stacks have?
    Class II
  81. The upper 25 feet of a heavy duty stack shall have what?
    a continuous covering of lead
  82. What are the intervals of air termainls on the rim  of stacks?
    not exceeding 8 feet
  83. How far shall air terminals extend above the heavy duty stack?
    > 18 inches <30 inches
  84. On heavy duty stacks how far above earth are down conductors to be protected from damage?
    At least 8 feet
  85. If ground rods are used for a heavy duty stack what is the diameter and length?
    5/8 inch and 10 feet long
  86. How far away does a metal water pipe system have to be to be bonded with the LPS of a stack?
    within 25'
  87. How far away do trunks of trees have to be from a structure to provide lightning protection?
    within 10 feet
  88. What are the three design concerns as it relates to open shelters?
    • Step potential
    • Touch potential
    • Sideflash (to person/animal)
  89. When protecting an open structure how many down conductors should there be?
    a down conductor for every corner
  90. How shall clamps be secured to ground rods and down conductors?
    • Make contact for 1 1/2 inches
    • Secured with at least two bolts
  91. When should connections to ground electrodes be made?
    • Not less than 1 foot below grade
    • Not less than 2 feet away from the foundation wall
  92. How far shall ground rods be extended vertically?
    not less than 10 feet
  93. What are the three things ground rods can be made of?
    • Cooper-clad steel
    • Solid Copper
    • Stainless Steel (corrosive)
  94. Masonry anchors are
    1/4" diameter
  95. What type of metal body must always be considered for bonding?
    non-isolated metal body
  96. How thick must metal be to be used as an air terminal or main cable conductor?
    At least 3/16" thick
  97. What is the minimum thickness and surface area of a ground plate?
    0.032 inches thick and 2 square feet
  98. What are the three approved materials for lightning protection?
    • Copper
    • Copper Alloys
    • Aluminum
  99. Nickel is compatible with?
    Copper
  100. Brass  is compatible with?
    Copper
  101. Tin is compatible with?
    Copper
  102. Lead is compatible with?
    Copper and Aluminum
  103. Stainless Steel is compatible with?
    Copper and Aluminum
  104. Monel is compatible with?
    Copper
  105. Magnesium is compatible with?
    Aluminum
  106. Zinc is compatible with?
    Aluminum
  107. Galvanized Steel is compatible with?
    Aluminum
  108. Wrought Iron is compatible with?
    Aluminum
  109. Galvalume is compatible with?
    Aluminum
  110. Batt Insulation
  111. Compacted Fill
  112. Concrete Block
  113. Concrete Block Fill
  114. Drywall
  115. Earth
  116. Face Brick
  117. Finished Lumber
  118. Gravel Fill
  119. Plywood
  120. Poured Concrete
  121. Precast Concrete
  122. Rigid Insulation
  123. Rough Lumber
  124. Steel
  125. Stone
  126. Bonding
    An electrical connection between an electrically conductive object and a component of a lightning protection system that is intended to significantly reduce potential differences created by lightning currents.
  127. Bonding Conductor
    A conductor used for potential equalization between grounded metal bodies or electrically conductive objects and a lightning protection system. The bonding conductors are normally smaller in size than current carrying conductors.
  128. Catenary Lightning Protection System
    A lightning protection system consisting of one or more overhead ground wires. (also known as overhead shielding)
  129. Combination Waveform Generator
    A surge generator with a 2 ohm internal impedance producing a 1.2/50 us open circuit voltage and an 8/20 short-circuit current wave shape.
  130. Copper-clad Steel
    Steel rod or wire with a coating of copper bonded it.
  131. Grounded
    Connected to earth or to some conducting body that is connected to earth ground.
  132. Heavy Duty Stack
    A smoke or vent stack with a flue that has a cross-sectional area greater than 500 square inches and a height greater than 75 feet.
  133. MCOV
    Maximum Continuous Operating Voltage
  134. Maximum Continuous Operating Voltage
    The maximum designated rms value of the power frequency voltage that can be continuously applied to the mode of protection of a surge protection device.
  135. Maximum Discharge Current
    The maximum instantaneous value of the current through the SPD having a 8/20 us waveform.
  136. lmax
    Maxium Discharge Current
  137. MLV
    Measure Limiting Voltage
  138. ln
    Nominal Discharge Current
  139. Nominal Discharge Current
    Peak value of 8/20 us current waveform selected by the manufacturer for which an SPD remains functional after 15 surges.
  140. Nominal System Voltage
    The nominal voltage (rms) of the power frequency supply.
  141. Normal Operating Voltage
    The normal ac power frequency voltage rating, as specified by the manufacturer, to which the surge protection device may be connected.
  142. TOV
    Temporary Over Voltage
  143. Transient
    a subcycle disturbance in the ac waveform that is evidenced by a sharp, brief discontinuity of the waveform. It may be of either polarity and may be additive to, or subtractive from the nominal waveform.
  144. VPR
    Voltage Protection Rating
  145. Voltage Protection Rating
    A rating (or ratings) selected by the manufacturer based on the measured limiting voltage determined when the SPD is subjected to a combination waveform with an open cicuit voltage of 6kV and a shortcircuit current of 3 kA. The value is rounded up to the next highest 100 V level.
  146. Combination Waveform Generator
    A surge gnerator with 2-ohm internal impedance producing a 1.2/50 us open circuit voltage and an 8/20 us short-circuit current wave shape.
  147. Lightning Electromagnetic Impulse (LEMP)
    Electromagnetic effects of lightning current, which includes conducted surges as well as radiated impulse electromagnetic field effects.
  148. Transient
    A subcycle disturbance in teh ac waveform that is evidenced by a sharp, brief discontinuity of the waveform. It can be of either polarity and can be additive to, or subtractive from, the nominal waveform.
  149. Maximum Continuous Operating Voltage (MCOV)
    The maximum designated rms value of the power frequency voltage that can be continuously applied to the mode of protection of a surge protection device.
  150. Measured Limiting Voltage (MLV)
    Maximum magnitude of voltage that is measured across the terminals of the surge protection device during hte application of impulses of specified waveshape and amplitude.
  151. Nominal System Voltage
    The nominal voltage (RMS) of the power frequency supply.
  152. Normal Operating Voltage
    The normal ac power frequency voltage rating, as specified by the manufacturer, to which the SPD may be connected.
  153. Voltage Protection Rating (VPR)
    A rating selected by the manufacturer based on the measured limiting voltage determined when the SPD is subjected to a combination waveform with an open circuit voltage of 6 kV and a shortcircuit curret of 3 kA. The value is rounded up to the next highest 100 V level.
  154. Zone of Protection Equation
  155. Bonding Distance
  156. What are you calculating when you use the Zone of Protection equation? (i.e. what is d?)
    horizontal protected distance
  157. What is h1 of the protected distance equation for zone of protection?
    height of the higher air terminal or protected roof
  158. What is h2 of the protected distance equation for zone of protection?
    height of the lower roof or object under consideration for protection
  159. What is R of the protected distance equation for zone of protection?
    rolling sphere radius = 150 feet
  160. What is h in the bonding distance formula?
    vertical distance between the bond being considered and the nearest lightning protection system bond (for buildings under 40 feet it can be considered the building height)
  161. What is n?
    • n = 1 where there is only one
    • n = 1.5 where there are only two
    • n = 2.25 where are are three or more
  162. What is Km in the bonding distance formula?
    • a value of 1 if the potential flashover is through the air
    • a value of 0.50 if through solid building material
  163. Sideflash distance from a mast formula
  164. What is the equation for sideflash distance from an overhead ground wire?
  165. Slope
    Rise/Run
  166. Class I - What is the cir. mils of the cross-section area of main conductor cable:

    Copper?

    Aluminum?
    Copper  57,400 cir. mils

    Aluminum 98,600 cir. mils
  167. Class I - What is the cir. mils of the cross-section area of bonding conductor cable:

    Copper?

    Aluminum
    Copper 26,240 cir. mils

    Aluminum 41,100 cir. mils
  168. Class I - What is the thickness of solid strip main conductor

    Copper?

    Aluminum?
    Copper 0.051 in.

    Aluminum 0.064 in.
  169. Roof Slope
  170. Class II.  What is the main conductor cable cross-section area for

    Copper?

    Aluminum?
    Copper  115,000 cir. mils

    Aluminum   192,000 cir. mils
  171. Class II.  What is the bonding conductor cable cross-section area for

    Copper?

    Aluminum?
    Copper  26,240 cir. mils

    Aluminum 41,100 cir. mils
  172. How are pitched roofs defined?
    If the span is 40' or less and a slope of 1/8 or greater 

    or

    if the span is more than 40' and a slope 1/4 or greater.
  173. What shall be of 96% conductivity when annealed?
    Copper

    4.2.2.1
  174. How can Aluminum be used?
    • 1. Aluminum can be used as long as there is no contact with the earth or the possibility of rapid deterioration.
    • 2. Aluminum must be electrical-grade aluminum.
    • 3. Aluminum will not come into contact with copper materials.
    • 4.2.2.3
  175. Where does bonding need to take place where metal pipe or tubing is used around the conductor?
    The top and the bottom shall be bonded to the pipe or tubing.

    4.4.2
  176. Aluminium materials shall not be used with how many inches of contact with the earth?
    18"
  177. Class II conductors from the higher portion

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