Wisconsin Contractors Institute Continuing Education

Transcription

1 IMPORTANT NOTE: You should have received an from us with a link and password to take your final exam online. Please check your for this link. Be sure to check your spam folder as well. If you still can t locate the , please contact us. We recommend that you circle your answers on a printed version before you start the online exam. Wisconsin Contractors Institute Continuing Education Article 250 Grounding & Bonding (Course #) 3.5 hours (Approved for 7.5 hours for Beginner Electrician, Commercial Electrical Inspector, Industrial Journeyman Electrician, Journeyman Electrician, Master Electrician, Residential Journeyman Electrician, Residential Master Electrician, and UDC-Electrical Inspector.) Wisconsin Contractors Institute N27 W23953 Paul Road, Suite 203 Pewaukee, WI

2 1) Ground-Fault Current Path This is the reference to the 2011 NEC Code Book. An electrically conductive path from the point of a ground on a wiring system through normally non current-carrying conductors, equipment, or the earth to the electrical supply source. A) Fault B) Electrode C) Bonding jumper system D) Conductor 2) 250.4(A)(1) Informational Note: An important consideration for limiting the imposed voltage is the routing of bonding and grounding electrode conductors so that they are not any longer than necessary to complete the connection without disturbing the permanent parts of the installation and so that permanent parts of the installation and so that unnecessary and loops are avoided. A) Marks B) Bends C) Lengths D) Grouping 3) 250.4(A)(4) Normally non-current- electrically conductive materials that are likely to became energized shall be connected together and to the electrical supply source in a manner that establishes an effective ground-fault current path. A) Limiting B) Grounding C) Bonding D) Carrying 4) (A) Objectionable Current The grounding of electrical systems, circuit conductors surge arresters, surge-protective devices, and conductive normally non-current-carrying of equipment shall be installed and arranged in a manner that will prevent objectionable current. A) Metal parts B) Bonding C) Grounding D) Phasing 5) 250.8(B) As pertaining to grounding connection devices or fittings that depend solely on solder be used. A) Shall B) Shall not C) Can D) Must

3 6) Clean Surfaces Nonconductive coatings (such as paint, lacquer, and enamel) on equipment to be grounded shall be removed from threads and other contact surfaces to ensure electrical continuity or be connected by means of fittings designed so as to make such removal unnecessary. A) Good B) Neutral C) Solid D) Permanent 7) (B) Ground Detectors Ungrounded alternating current systems as permitted in (A)(1) through (A)(4) operating at not less than 120 volts and not exceeding volts shall have ground detectors installed on the system. A) 1000 B) 480 C) 600 D) ) Grounding Service-Supplied Alternating-Current Systems The conductor connection shall be made at any accessible point from the load end of the service drop or service lateral to and including the terminal or bus to which the grounded service conductor is connected at the service disconnecting means. A) Grounded B) Grounding electrode C) Bonded D) Phase 9) Grounding Service-Supplied Alternating-Current Systems The additional grounding connection shall not be made on high-impedance grounded neutral systems. The system shall meet the requirements of A) Grid B) Electrode conductor C) System D) Encased 10) (5) A conductor shall not be connected to normally non-current-carrying metal parts of equipment, to equipment grounding conductor(s), or be reconnected to ground on the load side of the service disconnecting means except as otherwise permitted in this article. A) Phase B) Grounding C) Grounded D) Bonding 11) (C) Grounded Conductor Brought to Service Equipment Where an ac system operating at less than 1000 volts is grounded at any point, the grounded conductor(s) shall be run to each service disconnecting means and shall be connected to each disconnecting means grounded conductor(s) terminal or. A) Bus B) Conductor C) Electrode D) Bond

4 12) (C) Grounded Conductor Brought to Service Equipment A main bonding jumper shall connect the grounded to each service disconnecting means enclosure. A) System B) Conductor(s) C) Grid D) Area 13) (C) Exception: Where more than one service disconnecting means are located in a assembly listed for use as service equipment, it shall be permitted to run the grounded conductor(s) to the assembly common grounded conductor(s) terminal or bus. A) Listed B) Common C) Approved D) Single 14) (D) Grounding Electrode Conductor A grounding electode conductor shall be used to connect the equipment grounding conductors, the service-equipment enclosures, and, where the system is grounded, the grounded service conductor to the grounding electrode(s) required by Part III of this article. This conductor shall be sized in accordance with. A) B) C) D) ) Main Bonding Jumper and System Bonding Jumper Main bonding jumpers and system bonding jumpers shall be in the manner specified by the applicable provisions of A) Connected B) Soldered C) Ran D) Sized 16) (D)(1) General Where a service consists of more than a single enclosure as permitted in (A), the main bonding jumper for each enclosure shall be sized in accordance with (D)(1) based on the ungrounded service conductor serving that enclosure. A) First B) Smallest C) Newest D) Largest

5 17) (D)(3) Separately Derived System with More Than One Enclosure Where a separately derived system supplies more than a single enclosure, the system bonding jumper for each enclosure shall be sized in accordance with (D)(1) based on the largest ungrounded conductor serving that enclosure, or a single system bonding bonding jumper shall be installed at the source and sized in accordance with (D)(1) based on the equivalent size of the largest supply conductor determined by the largest sum of the areas of the corresponding conductors of each set. A) Branch B) Feeder C) Service D) Impedance 18) Grounding Separately Derived Alternating- Current Systems A separately derived ac system that is grounded shall comply with (A)(1) through (A)(8). Except as otherwise permitted in this article, a grounded conductor shall not be connected to normally non current carrying metal parts of equipment, be connected to equipment grounding conductors, or be reconnected to ground on the load side of the. A) System bonding jumper B) Transformer C) Area D) Location 19) (A)(2) A supply-side of the wire type shall comply with (C), based on the size of the derived ungrounded conductors. A) Bonding jumper B) Grounded conductors C) Ungrounded conductors D) Equipment bonding jumper 20) (A)(4) Grounding Electrode The grounding electrode shall be as near as practicable to, and preferably in the same area as, the grounding electrode conductor connection to the. Choose one answer. A) Conductor B) Grid C) System D) Attachment 21) (A (6) Grounding Electrode Conductor, Multiple Separately Derived Systems If installed, the common grounding electrode conductor shall be used to connect the grounded conductor of the systems to the grounding electrode as specified in (A)(4). A) Bond B) Grounding C) Electrode D) Separately derived

6 22) (A) Building(s) or structure(s) supplied by feeder(s) or branch circuit(s) shall have a grounding electrode or grounding electrode system installed in accordance with Part of Article 250. A) III B) II C) I D) IV 23) Permanently Installed Generators A conductor that provides an effective ground-fault current path shall be installed with the supply conductors from a permanently installed generator(s) to the first disconnecting mean(s) in accordance with. A) (1) or (2) B) (2) or (3) C) (B) or (C) D) (A) or (B) 24) Permanently Installed Generators If the is installed as a separately derived system, the requirements in shall apply. A) Transformer B) Generator C) Transfer switch D) Battery bank 25) Permanently Installed Generators If the generator is installed as a nonseparately derived system, and overcurrent protection is not integral with the generator, a supply-side bonding jumper shall be installed between the generator equipment grounding terminal and the equipment grounding terminal, bar, or bus of the disconnecting mean(s). A) Transfer switch B) Sub panel C) Assembly D) Panel board 26) High-impedance grounded neutral systems in which a grounding impedance, usually a resistor, limits the groundfault current to a low value shall be permitted for 3-phase ac systems of volts to 1000 volts if all the following conditions are met: A) 480 B) 240 C) 300 D) ) The system not be connected to ground except through the grounding impedance. A) Shall B) Must C) Will D) Can

7 28) The grounding impedance shall be installed between the grounding electrode conductor and the system point. Where a neutral point is not available, the grounding impedance shall be installed between the grounding electrode conductor and the neutral point derived from a grounding transformer. A) Bonded B) Impedance C) Equipment grounding D) Neutral 29) The system conductor from the neutral point of the transformer of generator to its connection point to the grounding impedance shall be fully insulated. A) Grounding B) Grounded C) Bonded D) Electrode 30) (D) The conductor connecting the neutral point of the transformer or generator to the grounding impedance shall be permitted to be installed in a separate raceway from the conductors. It shall not be required to run this conductor with the phase conductors to the first system disconnecting means or overcurrent device. A) Grounded B) Ungrounded C) Bonded D) Grounding 31) (F) The grounded electrode conductor shall be at any point form the grounded side of the grounding impedance to the equipment grounding connection at the service equipment or first system disconnecting means. A) Used B) Located C) Run D) Connected 32) Grounding Electrodes A metal underground water pipe in direct contact with the earth for 3.0 m ( ft) or more (including any metal well casing bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductor(s) or jumper(s), if installed. A) 6 B) 10 C) 5 D) 20

8 33) Grounding Electrodes At least structural metal member that is in direct contact with the earth for 3.0 m (10 ft) or more, with or without concrete encasement. A) 1 B) 2 C) 3 D) 4 34) (A)(5)(a) Grounding electrodes of pipe or conduit shall not be smaller than metric designator 21 (trade size ) and, where of steel, shall have the outer surface galvanized or otherwise metal-coated for corrosion protection. A) 3/4 B) 1/2 C) 5/8 D) 1/4 35) (A)(5)(b) Rod-type grounding electrodes of stainless steel and copper or coated steel shall be at least mm (5/8 in.) in diameter, unless listed. A) Gold B) Silver C) Zinc D) Nickel 36) (A)(6) Other listed grounding electrodes permitted. A) Shall not B) Cannot C) Will be D) Shall be 37) (B) Not Permitted for Use as Grounding Electrodes The following and materials shall not be used as grounding electrodes: (1) Metal underground gas piping systems (2) Aluminum A) Systems B) Grids C) Locations D) Devices 38) Grounding electrode conductors at the service, at each building or where supplied by a feeder(s) or branch circuit(s), or at a separately derived system shall be installed as specified in (A) through (F). A) Occupancy B) Facility C) Area D) Structure

9 39) (D) Where a service consists of more than a single enclosure as permitted in (A), grounding electrode connections shall be made in accordance with (D)(1), (D)(2), or (D)(3). A) True B) False 40) (D)(1) The common grounding electrode conductor shall be sized in accordance with , based on the sum of the circular mil area of the largest ungrounded service-entrance conductor(s). A) True B) False 41) (D)(1) The common grounding electrode conductor shall be sized in accordance with, based on the sum of the circular mil area of the largest ungrounded service-entrance conductor(s). A) B) C) D) ) (D)(1) The conductors shall be connected to the common grounding electrode conductor by exothermic welding or with connectors listed as grounding and bonding equipment in such a manner that the common grounding electrode remains without a splice or joint. A) Grounded B) Tap C) Phase D) Grounding 43) (D)(2) A grounding electrode conductor connected between the grounded conductor in each service equipment disconnecting means enclosure and the grounding electrode system. A) Must be B) Should be C) Shall be D) Will be 44) (D)(3) A grounding electrode conductor shall be connected to the grounded service conductor(s) in a or other accessible enclosure on the supply side of the service disconnecting means. A) Disconnect B) Wireway C) Panel D) Transformer

10 45) (D)(3) Common Location The grounding electrode conductor shall be in accordance with based on the serviceentrance conductor(s) at the common location where the connection is made. A) Sized B) Based C) Made D) Used 46) (F) Installation to Electrode(s) Grounding electrode conductor(s) and bonding jumpers interconnecting grounding electrodes shall not be installed in accordance with (1), (2), or (3). A) True B) False 47) (F)(1) The grounding electrode conductor shall be to be run to any convenient grounding electrode available on the grounding electrode system where the other electrode(s), if any, are connected by bonding jumpers that are installed in accordance with (C). A) Permitted B) Accessible C) Allowed D) Made 48) (F)(2) Grounding electrode conductor(s) shall be permitted to be run to or more grounding electrode(s) individually. A) 2 B) 1 C) 3 D) 5 49) (F)(3) Bonding jumper(s) from grounding electrode(s) shall be permitted to be connected to an aluminum or copper busbar not less than 6 mm x 50 mm (¼ in. x in.). The busbar shall be securely fastened and shall be installed in an accessible location. A) 3 B) 4 C) 5 D) 2 50) (F)(3) The grounding electrode shall be permitted to be run to the busbar. A) System B) Conductor C) Bond D) Grid

11 51) (F)(3) Where aluminum busbars are used, the installation shall comply with. A) (A) B) C) D) ) The size of the grounding electrode conductor at the, at each building or structure where supplied by a feeder(s) or branch circuit(s), or at a separately derived system of a grounded or ungrounded ac system shall not be less than given in Table , except as permitted in (A) through (C). A) Utility B) Service C) Transformer D) Disconnect 53) The connection of a grounding electrode conductor at the service, at each building or stricture where supplied by a feeder(s) or branch circuit(s), or at a separately derived system and associated bonding shall be made as specified (A) through (C). A) Electrode B) Connection C) Conductor D) Jumper(s) 54) (A) All elements used to terminated a grounding electrode conductor or bonding jumper to a grounding electrode shall be accessible. A) Mechanical B) Listed C) Rated D) Serviced 55) (A) Exception 2 Exothermic or irreversible compression connections used at terminations, together with the mechanical means used to attach such terminations to fire-proofed structural metal whether or not the mechanical means is reversible, shall not be required to be. A) Open B) Accessible C) Used D) Made 56) (B) Bonding jumpers shall be of sufficient length to permit removal of such equipment while retaining the integrity of the. A) Conductor B) Grounding electrode C) Grounding path D) System

12 57) Metal enclosures and raceways for service conductors and equipment shall be connected to the grounded system conductor if the electrical system is grounded or to the grounding electrode conductor for electrical systems that are not. A) Made B) Used C) Connected D) Rounded 58) Exception A metal elbow that is installed in an underground installation of rigid nonmetallic conduit and is isolated from possible contact by a minimum cover of 450 mm (18 in.) to any part of the elbow shall not be required to be connected to the grounded system or grounding electrode conductor. A) Conductor B) Bond C) Feeder D) Path 59) (A) The sheath or armor of a continuous underground metal-sheathed or armored service cable system that is connected to the grounded system conductor on the side shall not be required to be connected to the grounded system conductor at the building or structure. The sheath or armor shall be permitted to be insulated from the interior metal raceway or piping. A) Steel B) Ground rod C) Conductor D) Bond 60) Except as permitted by (I), metal enclosures and raceways for other than service conductors shall be connected to the conductor. A) Grounded B) Bonded C) Electrode D) Equipment grounding 61) Exception 2 Short sections of metal enclosures or raceways used to provide support or protection of cable assemblies form physical damage shall not be required to be connected to the equipment grounding. A) Conductor B) System C) Path D) Grid 62) (A) The non-current-carrying metal parts of equipment indicated in (A) shall be bonded together. A) (3) and (B)(5) B) (1) and (A)(2) C) (2) and (A)(5) D) (6) and (A)(2)

13 63) An bonding termination for connecting intersystem bonding and grounding conductors required for other systems shall be provided external to enclosures at the service equipment and at the disconnecting means for any additional buildings or structures. A) Accessible B) Connected C) Enclosures D) Intersystem 64) The intersystem bonding termination shall have the capacity for connection or not less than intersystem bonding conductors. A) One B) Three C) Four D) Five 65) (4) At the service equipment, be securely mounted and electrically connected to an enclosure for the service equipment, to the meter enclosure, or to an exposed nonflexible metallic service raceway, or be mounted at one of these enclosures and be connected to the enclosure or to the grounding electrode conductor with a minimum AWG copper conductor. A) 6 B) 4 C) 2 D) 8 66) Exception Exception: In existing buildings or structures where any of the intersystem bonding and grounding electrode conductors required by (B)(2), (B)(2), (F)(2), (B)(2), and exist, installation of the intersystem bonding termination is not required. A) (A) B) C) (B)(2) D) ) (B) Where for the reduction of electrical noise (electromagnetic interference) on the grounding circuit, an equipment e closure supplied by a branch circuit shall be permitted to be isolated from a raceway containing circuits supplying only that equipment by one or more listed nonmetallic raceway to the equipment enclosure. A) Installed B) Listed C) Made D) Used

14 68) Regardless of the voltage of the electrical system, the electrical continuity of non-current-carrying metal parts of equipment, raceways, and other enclosures in any hazardous (classified) locations as defined in shall be ensured by any of the methods specified in (B)(2) through (B)(4). A) Grounding B) Connecting C) Bonding D) Attachment 69) (D) A single common continuous equipment bonding jumper shall be permitted to two or more raceways or cables where the bonding jumper is sized in accordance with Table for the largest overcurrent device supplying circuits therein. A) Attach B) Supply C) Run D) Connect 70) (A)(2) The bonding jumper shall be sized in accordance with Table based on the rating o the overcurrent protective device for the circuit supplying the. A) Occupancy B) Service C) Transformer D) Building 71) (D)(1) Exception A separate bonding jumper to the metal water piping system shall not be required where the metal water piping system is used as the grounding electrode for the separately derived system and the system is in the area served. A) Bonding B) Grounding C) Water Piping D) Grounded 72) FPN See for use of air terminals. For further information, see NFPA , Standard for the Installation of Lightning Protection Systems, which contains detailed information on grounding,bonding, and distance form lightning protection systems. A) Connecting B) Sideflash C) Flashover D) Arc flash

15 73) Except as permitted in and (I), exposed, normally non current-carrying metal parts of equipment described in (A) through (K), and normally non currentcarrying metal parts of equipment and enclosures described in (L) and (M), shall be connected to an equipment grounding conductor, regardless of voltage. A) B) C) (F) D) ) (K) Permanently mounted electrical equipment and skids shall be to the equipment grounding conductor sized as required by A) Attached B) Connected C) Made D) Bonded 75) (I) Equipment supplied by Class 1 circuits shall be grounded unless operating at less than volts. Equipment supplied by Vlass 1 power-limited circuits, by Class 2 and Class 3 remote-control and signaling circuits, and by fire alarm circuits shall be grounded where systems grounding is required by Part II or Part VIII of this article. A) 50 B) 24 C) 12 D) 30 76) (M) Metal Well Casings. Where a submersible pump is used in a metal well casing, the well casing shall be to the pump circuit equipment grounding conductor. A) Ground B) Bonded C) Connected D) Attached 77) Exception Power-limited Class 2 or Class 3 cables, powerlimited fire alarm cables, or communications cables containing only circuits operating at less than volts where connected to equipment not required to be grounded in accordance with (I) shall be permitted to use a conductor with green insulation or green with one or more yellow stripes for other than equipment grounding purposes. A) 75 B) 50 C) 120 D) 240

16 78) (A) FPN See the UL guide information on FHIT systems for equipment grounding conductors installed in a raceway that are part of an electrical circuit protective system or a fire-rated cable listed to maintain circuit. A) Continuity B) Integrity C) Grounding D) Bonding 79) (A) Copper, aluminum, or copper-clad aluminum equipment grounding conductors of the wire type shall not be smaller than shown in Table , but in no case shall they be required to be larger than the conductors supplying the equipment. A) Service B) Transformer C) Enclosure D) Circuit 80) (C) Where a single equipment grounding conductor is run with multiple circuits in the same raceway, cable, or cable tray, it shall be sized for the largest cable, or. Choose one answer. A) Vault B) Gutter C) Cable tray D) Service mast 81) (D)(1) The equipment grounding conductor size shall not be smaller than determined by based on the rating of the branch-circuit short-circuit and ground-fault protective device. A) (A) B) C) D) ) (D)(2) Where the overcurrent device is an circuit breaker motor short-circuit protector, the equipment grounding conductor shall be sized not smaller than that given by (A) using the maximum permitted rating of a dual element time-delay fuse selected for branch-circuit and groundfault protection in accordance with (C)(1), Exception No. 1. A) Inverse time B) Intermittent delay C) Periodic duty D) Instantaneous trip

17 83) (E) The equipment grounding conductor in a flexible cord with a circuit conductor larger than 10AWG shall be sized in accordance with Table. A) B) C) D) ) (B) No automatic cutout or switch shall be placed in the equipment grounding conductor of a premises wiring system unless the opening of the cutout or switch disconnects all sources of. A) Energy B) Current C) Electricity D) Power 85) (A) The connection shall be made by bonding the equipment grounding conductor to the grounded service conductor and the grounding electrode conductor. A) True B) False 86) (B) True or False, For Ungrounded Systems: The connection shall not be made by bonding the equipment grounding conductor to the grounding electrode conductor. A) True B) False 87) Isolated sections of metal raceway or cable armor, where required to be grounded, shall be connected to an conductor in accordance with A) Grounded B) System C) Equipment grounding D) Bonded 88) An equipment bonding jumper shall be used to connect the grounding terminal of a grounding-type receptacle to a grounded box unless grounded as in (A) through (D). The equipment bonding jumper shall be sized in accordance with Table based on the rating of the overcurrent device protecting the circuit conductors. A) True B) False

18 89) (D) Where for the reduction of electrical noise (electromagnetic interference) on the grounding circuit, a receptacle in which the grounding terminal is purposely insulated from the receptacle mounting means shall be permitted. A) Installed B) Listed C) Rated D) Required 90) Where circuit conductors are spliced within a box, or terminated on equipment within or supported by a box, any equipment grounding conductor(s) associated with those circuit conductors shall be within the box or to the box with devices suitable for the use in accordance with (A) through (E). A) Bonded B) Identified C) Grounded D) Connected 91) (C) A connection shall be made between the one or more equipment grounding conductors and a metal box by means of a grounding screw that shall be used for no other purpose, equipment for grounding, or a listed grounding device. A) Installed B) Listed C) Used D) Made 92) For direct-current systems that are to be grounded, an bonding jumper shall be used to connect the equipment grounding conductor(s) to the grounded conductor at the source or the first system disconnecting means where the system is grounded. A) Unspliced B) Attached C) Exothermic welded D) Equipment 93) Exception 2 Current transformer secondaries connected in a three-phase delta configuration be required to be grounded. A) Shall B) Must C) Shall not D) Will 94) Instruments, meters, and relays operating with windings or working parts at less than 1000 volts shall be connected to the equipment grounding conductor as specified in (A), (B), or (C). A) True B) False

19 95) (B) Instruments, meters, and relays (whether operated form current and potential transformers or connected directly in the circuit) on switchboards having no live parts on the front of the panels shall have the cases connected to the equipment grounding conductor. A) True B) False 96) A system neutral point derived from a grounding transformer shall be permitted to be used for grounding over 1 KV. A) Low B) Impedance C) Nominal D) Systems 97) (A) The grounding impedance shall be inserted in the grounding conductor between the grounding electrode of the supply system and the neutral point of the supply or generator. A) Service B) Panel C) Transformer D) Vault 98) (C) The system conductor shall not be connected to ground, except through the neutral grounding impedance. A) Bond B) Neutral C) Grid D) Bare 99) (D) Equipment grounding conductors shall be permitted to be bare and shall be connected to the ground bus and grounding electrode. A) Electrically B) Physically C) Mechanically D) Completely 100) Where the system is 3-phase, 4-wire, delta connected in which the midpoint of one phase winding is used a circuit conductor. A) As B) While C) After D) Before

20 101) 250.2: Definitions. Bonding Jumper, Supply-Side A conductor installed on the supply side of a service or within a service equipment enclosure(s), or for a separately derived system, that ensures the required electrical conductivity between parts required to be electrically connected. A) PVC B) Steel C) Raceway D) Metal 102) Objectionable Current Temporary currents resulting from conditions, such as ground faults, shall not be classified as objectionable current for the purposes specified in 250.6(A) and (B). A) Abnormal B) Strange C) Unique D) Normal 103) (C) Marking Ungrounded systems shall be marked Ungrounded System at the source or first disconnecting means of the system. The marking shall be of sufficient durability to withstand the environment involved. A) Permanently B) Legibly C) Obviously D) Completely 104) (A) (2) A supply-side bonding jumper be required to be larger than the derived ungrounded conductors. A) Shall B) Shall not C) Must D) Will 105) (A) (6) Each tap conductor shall connect the grounded conductor of the separately derived system to the common grounding electrode. A) Tap B) Section C) Bond D) Conductor