Grounding II
The equipment grounding conductor for PV output or source circuits can be no smaller than 10 AWG copper.
False
The equipment grounding conductor for an electric sign or outline lighting system must be a wire type.
False
A ground fault is an unintentional, electrically-conductive connection between an ungrounded conductor of an electrical circuit and the normally non-current-carrying conductors, metallic enclosures, metallic raceways, metallic equipment, or earth.
True
A non-grounding-type receptacle is permitted to be replaced with another non-grounding-type receptacle where no grounding means exists in the outlet.
True
An equipment grounding conductor is not required for a ground-fault circuit interrupter to operate, but the supply system must be grounded.
True
Only if a cable assembly shield is a concentric strand or conductive tape type and suitable for ground-fault current performance is the shield permitted to serve as the required equipment grounding conductor.
True
PV array equipment grounding conductors and grounding electrode conductors not larger than 10 AWG installed in raceways are permitted to be solid.
True
The equipment grounding conductor(s) installed with circuits supplied by isolated power systems are permitted to be installed inside or outside the raceway for the branch circuit and must be connected to the reference grounding bus within the isolated power system enclosure.
True
The feeder run from the service disconnecting means or the feeder disconnecting means located no more than 30 feet from the mobile home must contain an insulated grounded (neutral) conductor and a separate equipment grounding conductor.
True
The grounding impedance device for an impedance grounded neutral system has to be installed in series with the grounding electrode conductor and the neutral point of the system source, which could be located at a transformer or a generator.
True
The neutral conductor of solidly grounded medium-voltage systems can be bare when installed as an overhead conductor, although only the portion installed overhead is permitted to be bare in this case.
True
Where flexible metal conduit or liquidtight flexible metal conduit is installed in a hazardous (classified) location, an equipment bonding jumper is required to be installed either on the inside or on the outside of the conduit and the conduit cannot serve as an equipment bonding jumper or equipment grounding conductor even if the conditions in 250.118(5) and (6) are satisfied.
True
One of the most important elements of farm wiring systems, especially where dairy cattle are involved, is to isolate the ? from the equipment grounding conductor and non-current-carrying metal parts of the electrical system at barns, milking parlors, and so forth.
c. system neutral conductor
A ? system is an electrical source, other than a service, having no direct connection(s) to the circuit conductors of any other electrical source, other than those established by grounding and bonding connections.
d. separately derived
A ? is typically used to establish a new voltage level, lower the power source impedance, and isolate part of the power distribution system.
d. separately derived system
Generally in hazardous (classified) locations, locknuts installed on each side of the enclosure, or a locknut on the outside and a bushing on the inside, ? be used for bonding.
d. shall not
Ground-fault protection of equipment is generally required for ? grounded ? electrical services and feeders of more than 150 volts to ground but not exceeding 1,000 volts phase-to-phase for each disconnect rated 1,000 amperes or more.
d. solidly / wye
The grounding electrode conductor for a separately derived system is required to be connected to the grounded conductor at the same location where the ? is installed.
d. system bonding jumper
A trolley frame and bridge are not considered grounded through the bridge and trolley wheels and tracks; a separate ? is required around the wheel-to-track contact.
a. bonding jumper
When performing a basic ? test, a separate voltmeter, ammeter, and power supply are used to measure the grounding system resistance between two points.
a. earth resistance
Equipment and systems that are not services, such as solar photovoltaic (PV) systems, and are connected to the line side of service equipment, shall be permitted to be ? systems.
a. either ungrounded and grounded
A signal reference structure (grid) installed in an information technology room is required to be connected to a(n) ? .
a. equipment grounding conductor
Electric signs and metal equipment of outline lighting systems, other than the portable and double-insulated types, shall be grounded by connecting them to the ? of the supplying branch circuit or feeder.
a. equipment grounding conductor
The neutral conductor(s) within a mobile home or a manufactured home must be insulated from ground, grounded metal parts, and any ? .
a. equipment grounding conductor(s)
A(n) ? is a protective device for limiting surge voltages by discharging or bypassing surge current. It also prevents continued flow of follow current while remaining capable of repeating these functions.
c. surge arrester
In some engineered grounding system designs, a grounding electrode known as a(n) ? is often specified for installation at each manhole, transformer, or substation.
d. triad grounding electrode
From the choices below, identify the grounding electrodes permitted by 250.52(A) for use as grounding electrodes at a separate building or structure.
All but I. and V.
Bonding connections for metal parts of signs and outline lighting systems are permitted to be made using sheet metal screws.
False
For a PV system installed on a building with an AC service and two separate grounding electrode systems installed, one for the DC side and one for the AC side, the two grounding electrode systems are not required to be bonded together.
False
GFCI protection for receptacles is required in Category 1 (critical care) spaces where the toilet and basin are in the patient rom.
False
Ground-fault circuit-interrupter protection for personnel is required for receptacles installed in those Category 1 (critical care) spaces where a toilet and basin are installed within the patient room.
False
In a patient care space, the branch-circuit wiring can be installed in PVC conduit as long as two insulated copper EGCs are included with the other circuit conductors.
False
In multi-grounded neutral systems, the system neutral is typically derived and grounded only at the source location, and then distributed for long distances.
False
Where a delta-connected system over 1,000 volts is used to supply portable or mobile equipment, a neutral point and system neutral are not permitted to be derived for grounding purposes.
False
Where a four-foot section of listed flexible metal conduit is installed in a rigid metal conduit run in a Class I, Division 2 location for a circuit rated at 30 amperes, equipment bonding jumpers are not required because the flexible metal conduit is less than six feet in length.
False
Where flexible metal conduit is installed for a 20-ampere circuit in a Class I, Division 2 location, it shall comply with the requirements of 250.118(5) to perform as an effective path for ground-fault current.
False
Where supplying portable or mobile equipment, electrical systems of over 1,000 volts must not be grounded.
False
A metallic insulation shield encircling the current-carrying conductors of a cable assembly shall be permitted to serve as an equipment grounding conductor if it is rated for the clearing time of the ground-fault protective device operation without damaging the metallic shield.
True
An intersystem bonding termination (IBT) for connecting intersystem bonding conductors shall be provided external to enclosures at the service equipment or metering equipment enclosure and at the disconnecting means for any additional buildings or structures. If an IBT is used, the terminals shall be listed as grounding and bonding equipment.
True
Bronze is a Code-compliant conductor material for a radio antenna grounding electrode conductor.
True
Dry conditions and freezing temperatures expand the soil around grounding electrodes and increase the resistance of the connection between the grounding electrode(s) and ground.
True
Each agricultural building or structure has to meet the provisions in 250.32 and has to meet the sizing and connection rules in 547.9(B)(1), (2), and (3). Therefore, the minimum size required for the EGC must be no smaller than the largest supply conductor for the building if the same conductor material is used.
True
Electrical systems that supply only industrial electric furnaces for melting, refining, tempering, and so forth are permitted to be grounded, but not required to be grounded.
True
Equipment associated with pools and similar installations is generally required to be connected to a branch circuit that includes an insulated copper equipment grounding conductor.
True
Exposed non-current-carrying metal parts of portable or mobile equipment must be grounded by connection to an equipment grounding conductor that is connected to the point at which the system neutral impedance is grounded.
True
Ground loops (current circulating on conductive parts) can create electrical shock hazards and can create problems for electrical equipment.
True
Ground resistance testers output a voltage that is at a frequency other than 60 hertz to ensure an accurate measurement.
True
Ground-fault circuit interrupters provide protection for persons.
True
Regardless of the photovoltaic system voltage, all equipment, metal frames, module frames, and conductor enclosures must be grounded in accordance with Sections 250.134 and 250.136.
True
Single-point grounding of a system of more than 1,000 volts means the system is grounded at only one point, and no neutral-to-ground connections can be made downstream of that initial grounding location.
True
Soil resistance measurements are taken to determine the best location for the grounding electrode, grid, or grounding system.
True
Specific methods of bonding of metal raceways installed in a hazardous (classified) location are required even if there is an EGC or equipment bonding jumper installed inside the raceway.
True
The NEC clarifies that the bonding required for a swimming pool must be installed to reduce voltage gradients in the pool area as described in Article 680.
True
The bonding methods required for hazardous (classified) locations must extend to all intervening metal raceways and back to the applicable service or separately derived system grounding point.
True
The circuit-breaker types of GFCI open the entire branch circuit if a ground fault occurs, while outlet types only open a portion of the circuit.
True
If the overcurrent protective device is not located on a generator outside that supplies a separate building or structure, then the feeder is on the line side of an overcurrent device. What is the minimum size supply-side bonding jumper (copper) required with a 400-ampere feeder from an outdoor generator to the building disconnecting means? (Note: The size of the largest ungrounded phase conductor supplied by the generator is 750 kcmil aluminum or copper-clad aluminum.)
a. 1/0 AWG
Where a generator separately derived system is installed and there is no overcurrent protective device at the generator, what is the minimum size required for the supply-side bonding jumper (copper) installed with the ungrounded derived phase conductors to the first disconnecting means enclosure if the ungrounded phase conductors are 750 kcmil aluminum or copper-clad aluminum?
a. 1/0 AWG
What is the minimum-size copper equipment grounding conductor required for an 800-ampere, 2,300-volt feeder installed in PVC conduit?
a. 1/0 AWG copper
Which of the following electrical systems is required to be grounded?
a. 120V, single-phase system
If the voltage on the secondary side of a transformer is less than ? and the voltage on the primary side of the transformer exceeds ? to ground, the secondary side shall be grounded.
a. 50 V / 150 V
If a building or structure served has no intersystem bonding termination, the bonding conductor or grounding electrode conductor is required to be connected to the nearest accessible location on any but which of the following?
a. A metal gas piping system
In health care facility power systems where an additional level of GFPE is provided on the load side of the service GFPE, the additional level is not permitted on the load side of the ? .
a. essential system transfer switch
For sensitive electronic equipment, the ungrounded conductors have a voltage of 120 volts between them, and from each ungrounded conductor to the neutral of such systems the voltage is ? .
b. 60 V
What is the minimum size required for the bonding conductor for an equipotential plane in an agricultural facility?
b. 8 AWG copper
Where the option to install a patient equipment grounding point is applied in a health care facility, what is the minimum size required for the equipment bonding jumper installed to the grounding terminal of each receptacle serving that location?
b. No smaller than 10 AWG copper
The system bonding jumper for a separately derived system must be sized in accordance with ? .
b. Section 250.28(D)
If overcurrent protection is not provided where the conductors originate at a grounded separately derived system source supplying a separate building or structure, the installation must comply with ? .
b. Section 250.30(A)
The general requirements for grounding and bonding for both grounded and ungrounded systems are located in ? .
b. Section 250.4
The grounding electrode conductor for a single separately derived system is required to be sized using which NEC table?
b. Table 250.66
The components identified in Section 680.26(B) shall be connected to a bonding grid with a ? conductor (insulated, covered, or bare) not smaller than 8 AWG.
b. solid copper
A scale of ? is used to measure pH.
c. 0 to 14
A distance of at least ? must be maintained from a nonmetallic conduit containing a high-voltage circuit operating at 100 hertz or less.
c. 1 1/2"
What is the minimum size wire-type equipment grounding conductor required for a 600-ampere, 12,470-volt feeder primary circuit supplying a unit substation?
c. 1 AWG copper
If the grounding electrode conductor connection for a photovoltaic DC system is connected only to a rod, pipe, or plate electrode, the largest grounding electrode conductor required is ? copper.
c. 6 AWG
Where a separate grounding electrode is installed for communications systems equipment on a commercial building, the minimum-size bonding jumper required between the communications grounding electrode and power grounding electrode system at the building or structure served must not be less than ? copper.
c. 6 AWG
For PV systems that are stand-alone units, the grounding electrode system has to meet the provisions in Part VIII of Article 250 and the DC system grounding electrode conductor is required to be as large as the largest output conductor supplied by the PV system or at least ? , whichever is larger.
c. 8 AWG
The bonding conductor for a hydromassage bathtub shall not be smaller than ? solid copper.
c. 8 AWG
? is defined as a system intended to provide protection of equipment from damaging line-to-ground fault currents by operating to cause a disconnecting means to open all ungrounded conductors of the faulted circuit.
c. Ground-fault protection of equipment
Where an alternate power source is provided with transfer equipment that includes a switching action in the grounded conductor, which of the following applies?
c. Shall be grounded according to 250.30(A)
Metal water piping and interconnected metal building framing that exists in the area served by a separately derived system is required to be bonded to the grounded conductor of that separately derived system, and ? is used to size this bonding jumper or conductor.
c. Table 250.102(C)(1)
The size of the equipment grounding conductor for PV source and output circuits must be in accordance with Section 690.45, and the general rule is to size the EGC with PV output or source circuits using ? .
c. Table 250.122
In a grounding electrode system, the ? is a conducting object through which a direct connection to earth is established.
c. grounding electrode
A distance of at least ? must be maintained from a nonmetallic conduit containing a high-voltage circuit operating at above 100 hertz.
d. 1 3/4"
If a feeder supplied by a 4,160-volt system is protected at 400 amperes, what is the minimum-size aluminum equipment grounding conductor required for the circuit?
d. 1 AWG
Where the grounding electrode system for the DC side of a PV installation is installed using a 6 AWG copper grounding electrode conductor, and the grounding electrode conductor for the AC system is 1 AWG copper, what is the minimum size required for the bonding conductor that must connect the two grounding electrode systems together?
d. 1 AWG copper
Section 230.95 requires ground-fault protection of all solidly-grounded wye electrical services of more than 150 volts to ground but not exceeding 1,000 volts phase-to-phase for each service disconnect rated ? or more.
d. 1,000 A
Flexible metal conduit is permitted as a bonding means in lengths not exceeding ? for conductive parts associated with a neon sign secondary circuit.
d. 100'
Medium- and high-voltage cables above ? are generally required to be shielded, and this shielding is usually in the form of either a conductive tape or stranded conductors.
d. 2,000 V
Where the grounded conductor for a 5-kilovolt service is installed with the ungrounded service conductors to the service disconnecting means, if the size of the largest ungrounded service conductor is 750 kcmil copper, what is the minimum size grounded conductor required to be installed with the service conductors?
d. 2/0 AWG
For one- or two-family dwellings, the primary protector bonding conductor or grounding electrode conductor shall be as short as practicable, and generally must not exceed ? in length.
d. 20'
Bonding for an indoor spa or hot tub has to be accomplished by which of the following methods?
d. Any of the above
The specific sizing requirements and installation requirements for grounding electrode conductors installed for a network-powered broadband communications system are located in which NEC article?
d. Article 800
Which NEC article covers premises-powered optical fiber-based broadband communications systems that provide any combination of voice, video, data, and interactive services through an optical network terminal?
d. Article 840
A zero-sequence-type GFPE typically consists of which of the following components?
d. II., III., and V.
? contains the requirements for ground-fault protection for personnel using temporary power at buildings or structures or on equipment used by personnel during construction, remodeling, maintenance, repair, or demolition of buildings, structures, equipment, or similar activities.
d. NEC 590.6
? provides a method for installing an equipment grounding conductor for receptacles that are being replaced at a location where an equipment grounding conductor is desired but is not present.
d. Section 250.130(C)
The bonding means required in 501.30(A) are generally required to be installed from the hazardous (classified) location to the ? or point of grounding of a separately derived system that is the source of the circuit.
d. service equipment
Non-shielded cables are permitted for circuits over 5,000 volts, but only under which of the following restrictive conditions?
f. None of the above
The bonding conductor or grounding electrode conductor for a communications system is required to be ? and shall be permitted to be insulated, covered, or bare.
listed
Installing a patient equipment grounding point is ? for improving electrical safety in a patient care vicinity.
optional
The term patient care vicinity refers to a distance of ? horizontally from the nominal patient bed location in a health care facility.
6
Which of the following is not considered an effective ground-fault current path?
Earth
A cause of high ground resistance is a rising water table that leaves the grounding system in wetter soil compared to when the system was installed.
False
Clamp-on leakage current ammeters are typically used to measure leakage currents on ? conductors.
Grounding electrode
Common receptacle types include standard duplex, isolated ground types, and GFCI (ground-fault circuit interrupter) receptacles.
True
What is the minimum number of equipment grounding conductor paths required for a feeder supplying branch circuits that serve a patient care space?
a. 1
For ground-fault protection of equipment, what is the maximum time-delay for ground-fault currents that exceed 3,000 amperes?
a. 1 second
Manufacturers of sensitive electronic equipment often specify a required maximum ground resistance of ? or less for proper equipment operation.
a. 1 Ω
For portable or mobile equipment that is grounded, the voltage developed between the frame of the equipment and ground by the flow of ground-fault current shall not exceed ? .
a. 100 V
The system bonding jumper for a separately derived system has to be installed and sized in accordance with ? .
a. 250.28(A) through (D)
Section 517.13(A) requires that all ? serving patient care spaces be provided with a ground path for fault current by installation in a metal raceway system or cable armor or sheath assembly that qualifies as an equipment grounding conductor in accordance with Section 250.118.
a. branch circuits
Where a pole-mounted electric sign is connected to a grounding electrode, the electrode is referred to as a(n) ? grounding electrode.
auxiliary
The maximum setting for ground-fault protection of equipment shall be ? , and the maximum time delay shall be one second for ground-fault currents equal to or greater than ? .
b. 1,200 A / 3,000 A
The neutral of solidly grounded systems is never permitted to be smaller than ? of the ungrounded conductor supplied by the system.
b. 20%
The ? is the conductor connected to the neutral point of a system that is intended to carry current under normal conditions.
c. neutral conductor
Which of the following are common methods of grounding systems over 1,000 volts?
d. All of the above
The NEC requires all exposed non-current-carrying metal parts of ? to be grounded and bonded.
d. all of the above
Which of the following are the primary purposes of shielding for medium- and high-voltage cables?
e. All of the above
If the grounding electrode conductor for a separate building or structure is connected to only a concrete-encased electrode(s), the maximum size required is a(n) ? .
4 AWG copper conductor
A system over 1,000 volts that is solidly grounded at only one point is referred to by the NEC as a ? .
A system over 1,000 volts that is solidly grounded at only one point is referred to by the NEC as a ? .
What is the phase-to-ground voltage of a 4,160-volt grounded wye-connected system?
c. 2,400 V
The intersystem bonding termination device is required to consist of a set of terminals with the capacity for connection of not less than ? intersystem bonding conductors.
c. 3
A ground-fault circuit interrupter operates simply by measuring the current in the supply and return current-carrying conductors of the circuit and by monitoring for an imbalance that exceeds ? .
c. 4 to 6 mA
Any underground metal structures, such as piping and framing, should be bonded to a substation grid and the minimum size of the grid conductor should be no less than ? copper and no less than ? of the capacity of the system.
c. 4/0 AWG / 25%
A(n) ? conductor is a conductor used to connect the system grounded conductor or the equipment to the grounding electrode or to a point on the grounding electrode system.
c. grounding electrode
A(n) ? receptacle, identified by an orange triangle, is used to reduce electromagnetic interference (electrical noise) problems by running a separate insulated equipment grounding conductor back to the grounding point on an electrical service or system grounding point on a separately derived system.
c. isolated grounding
A warning label is generally required to be mounted on or adjacent to the ? of a manufactured home and reads as follows:
c. service equipment
The neutral conductor of a multi-grounded neutral system generally has to be connected to ground (the Earth) at intervals not exceeding ? if the only purpose is for bonding the neutral to a grounding electrode.
d. 1,300'
What is the minimum size bonding conductor required for bonding metal parts associated with the high-voltage secondary circuit for a neon sign or outline lighting system?
d. 14 AWG copper
What does the NEC indicate that the phase-to-ground voltage should be for an ungrounded 240-volt, delta-connected system?
d. 240 V
The neutral of solidly grounded systems is generally not permitted to be smaller than ? of the ungrounded conductor supplied by the system.
d. 33 1/3%
Which of the following AC systems is permitted to be grounded, but not required to be grounded?
d. 480-volt delta, 3-phase, 3-wire system
Which of the following voltage and phase arrangements requires ground-fault protection of equipment for each service disconnecting means rated at 1,000 amperes or greater?
d. 480Y/277V, 3-phase, 4-wire, wye-connected
What is the minimum size required for an aluminum grounding electrode conductor or bonding conductor installed for a television antenna system or equipment?
d. 8 AWG
Ground-fault circuit-interrupter protection is required for receptacles installed within ? of a sink in a dwelling unit.
d. All of the above
The NEC has special requirements for grounding and bonding in hazardous (classified) locations. These requirements can be found in ? .
d. All of the above
Equipment grounding conductors that are not part of a cable assembly and are installed with feeders of more than 1,000 volts must generally be sized ? .
d. using Table 250.122
Any electrical equipment located within ? of the inside walls of a swimming pool or other specified body of water must be grounded.
e. both a. and b.
Which of the following are common shock severity factors for humans?
f. All of the above
An ESD meter measures the voltage of the static charge and polarity of the voltage by making contact with a conductive or insulated surface.
False
Isolated grounding receptacles are only permitted in a patient care vicinity if there is a surge protective device installed for the circuit.
False
The difference between a standard clamp-on ammeter and a clamp-on leakage current ammeter is that a clamp-on ammeter can accurately measure currents of a few milliamperes.
False
The higher the measured ground resistance, the more efficiently the effective ground-fault current path will facilitate the operation of the overcurrent protective device(s).
False
The higher the measured pH is above seven, the greater the acidity of the substance.
False
The terminals of an intersystem bonding termination are not required to be listed as grounding and bonding equipment, but are required to be identified.
False
A main bonding jumper is the connection between the grounded circuit conductor and the equipment grounding conductor, the supply-side bonding jumper, or both, at the service.
True
All receptacles used with systems covered in Article 647 must have unique configurations and be identified for use with this type of system.
True
Devices listed and identified for bonding metallic frames of PV modules shall be permitted to bond exposed metallic module frames to the metal frames of PV modules.
True
Grounding, in the simplest form, is the process of connecting a system or an electrically conductive object to ground (the earth).
True
If a building or structure served has an intersystem bonding termination as required by 250.94(A), the bonding conductor for an antenna and radio distribution system shall be connected to the intersystem bonding termination.
True
In a service equipped with ground-fault protection of equipment that is a zero-sequence-type, the GFPE monitors and operates when ground-fault current (at a predetermined and preset level) causes an imbalance between the three ungrounded phase conductors and the neutral conductor that pass through the same sensing window (CT) of the equipment.
True
In addition to electromagnetic interference (noise) problems, a static electric charge can also cause false operation, failure, or damage to sensitive electrical and electronic equipment.
True
Information technology equipment is required to be grounded by connection to an equipment grounding conductor of the branch circuit, or to be double insulated.
True
Isolated grounding-type receptacles are not permitted to be installed in patient care vicinities of health care facilities.
True
On a dry day, a person can develop a static charge of several thousand volts.
True
The purpose of grounding and bonding for communications systems and equipment is to provide a level of shock protection and limit damage from voltage surges created by lightning, line surges, or unintentional contact with higher-voltage lines.
True
The bonding conductor used for bonding metal parts (dead metal) of signs and outline lighting systems together and to the branch-circuit equipment grounding conductor shall not be smaller than ? copper.
a. 14 AWG
Which of the following are methods to reduce static electricity problems in hazardous (classified) locations?
a. I. and III.
Multiple separately derived systems that are connected in parallel are considered ? system(s).
a. a single separately derived
A ? is defined as a reliable conductor used to ensure the required electrical conductivity between metal parts required to be electrically connected.
a. bonding jumper or conductor
A(n) ? is an intentionally constructed, low-impedance electrically conductive path designed and intended to carry current during ground-fault conditions from the point of grounding on a wiring system to the electrical supply source, and is intended to facilitate the operation of the overcurrent protective device or ground-fault detectors on a high-impedance system.
a. effective ground-fault current path
Ground-fault protection of equipment is required to be performance tested when first installed on site, and a record of this performance testing is required to be made to the ? ?
a. the authority having jurisdiction
Where a multi-grounded neutral system of more than 1,000 volts is installed, the connections to ground from the neutral conductor must be generally made at intervals not exceeding ? .
b. 1,300'
The grounding of outdoor industrial substations includes the grounding of the fence and other supporting structures, the grounding of all equipment and conductor enclosures, and the grounding of the neutral. A ground bus or grid should be established extending about ? outside the periphery of the fence.
b. 3'
Where a separately derived system is installed outdoors and connected only to a rod, pipe, or plate electrode, what is the largest grounding electrode conductor required?
b. 6 AWG copper
? is the neutral point of a pH scale.
b. 7
All 15- and 20-ampere receptacles supplied by circuits from a sensitive electronic system are required to be ? .
b. GFCI protected
What type of GFPE device is shown?
b. Neutral ground strap type
Where a common grounding electrode conductor is installed for multiple separately derived systems, grounding electrode conductor taps are required to be connected to the common grounding electrode conductor using any of the following methods except ? .
b. a western union style connection
Not connected to ground or to a conductive body that extends the ground connection defines which of the following Code terms?
Ungrounded
What is the minimum size grounding electrode conductor required for a 400-ampere feeder supplying a panelboard installed in a structure, if the size of the largest ungrounded conductor of the feeder is 600 kcmil aluminum, and the grounding electrode is a metal in-ground support structure (building steel)?
c. 1/0 AWG copper
Where a DC system, other than a 3-wire balancer set, has a 250 kcmil copper grounded (neutral) conductor connected, the grounding electrode conductor shall not be required to be larger than ? .
c. 3/0 copper
A 400-ampere feeder made up of four 600 kcmil copper conductors and one size 3 AWG copper equipment grounding conductor is installed to supply a separate building. The only grounding electrode present is a metal in-ground support structure for the building. What is the minimum size grounding electrode conductor required for the building served?
1/0 AWG copper
If PVC conduit is installed for an 800-ampere feeder supplying a separate building, what is the minimum size wire-type copper equipment grounding conductor required to be installed with the feeder conductors?
1/0 AWG copper
A connection to ground through a grounding electrode system is generally required at separate buildings or structures to establish a reference to ground at that location.
True
Which of the following conditions is not required to qualify for installation and use of a high-impedance grounded neutral system?
b. Continuity of power is required.
A ? equipment grounding conductor is the minimum size required for a 1,000-ampere feeder supplying a separate building or structure.
4/0 AWG aluminum
Where the grounding electrode for a separate building or structure is only a single ground rod or two ground rods, what is the maximum-size copper grounding electrode conductor required if the feeder supplying the separate building or structure is sized at 2,500 amperes?
6 AWG
Class 2 load-side circuits for suspended ceiling low-voltage power grid distribution systems are required to be supplied by grounded systems.
False
Which of the following systems is not required to be grounded because, if grounded, the phase-to-ground voltage would exceed 150?
d. 480V, 3-phase delta system
The disconnecting means installed in the feeder supplying a separate building or structure has to always be suitable for use as service equipment.
False
Where grounding electrode conductor taps are used for multiple separately derived systems, each grounding electrode conductor tap must be sized using Table 250.66 based on the largest ungrounded derived phase conductor(s) of the individual derived system it serves.
True
Where no grounding electrodes are present at a separate building or structure served by a feeder, a grounding electrode in accordance with 250.50 is required to be installed.
True
When an ungrounded system (source) supplies separate buildings or structures by a feeder, the requirements in ? apply.
d. All of the above
The system bonding jumper for a separately derived system is permitted to extend beyond the enclosure where it originates.
False
Using the same grounding electrode as the building electrical service keeps the conductive parts of communications equipment at or close to the same ground (earth) potential in normal operation. In abnormal events, such as surges related to lightning strikes to or close to the building, the objective of grounding and bonding in accordance with the NEC is to keep conductive parts of electrical power systems and limited-energy communications systems at the same potential, as potentials rise and fall during high-surge events such as lightning strikes.
True
Voltages on a conductive surface are generally at the same potential at all points of the surface, and this can be measured with a voltmeter.
True
When measuring the resistance to ground in a grounding system at the location where the grounding resistance meter will be connected, an ammeter measurement (reading) of more than one ampere indicates that there is a ground leakage current problem that must be corrected before proceeding with ground resistance measurements.
True
Where an AC system operating over 1,000 volts is grounded at any point and is provided with a grounded conductor at the service point, a grounded conductor is required to be installed and routed to each service disconnecting means grounded conductor(s) terminal bar or bus in the service equipment.
True
In existing buildings or structures where any of the intersystem bonding and grounding electrode conductors required by 770.100(B)(2), 800.100(B)(2), and 810.21(F)(2) exist, installation of the intersystem bonding termination is not required. In this case, an accessible means external to enclosures for connecting intersystem bonding and grounding electrode conductors is permitted at the service equipment and at the disconnecting means for any additional buildings or structures by which one of the following means?
d. Any of the above locations
The specific grounding and bonding requirements for an information technology room are located in which article of the NEC ?
d. Article 645
A conducting object through which a direct connection to the Earth is established best defines which of the following?
d. Grounding electrode
Photovoltaic DC systems that are solidly grounded have to be connected to a grounding electrode system in accordance with ? ; for ungrounded DC systems, the grounding electrode requirements of Section 250.169 apply.
250.166
An equipment grounding conductor for a crane shall be only a copper-insulated wire sized at not less than 10 AWG.
False
Equipment grounding includes protecting a building or outside structure from lightning strikes by providing the lightning with a diversion path to ground through an installed lightning protection system.
False
Flat-topping is a condition that occurs when a sine wave has higher peaks from current drawn only at the peaks of the voltage.
False
For a 12,470-volt multi-grounded neutral system, the maximum length of 1,300 feet between grounding connections shall not be exceeded even if doing so requires only the removal of a cable sheath to accomplish the grounding connection.
False
In industrial establishments only, where the conditions of maintenance and supervision ensure that only qualified personnel are involved, an assured EGC program as specified in 590.6(A) Exception is not permitted for receptacle outlets used to supply equipment that would create a greater hazard if power is interrupted or that have a design that is not compatible with GFCI protection.
False
Metal faceplates on switches and receptacles installed in patient care locations are required to be connected to two equipment grounding conductor paths that are specified for branch circuits in Section 517.13.
False
Remote parts of a section sign or outline lighting system supplied by a Class 2 power supply are required to be bonded to the equipment grounding conductor of the branch circuit supplying the system.
False
Surge arresters are required by the NEC for systems over 1,000 volts.
False
Systems supplying cranes that operate over Class III locations are required to be grounded.
False
The 10 AWG copper conductor used to bond the equipment grounding terminal bar of normal and essential panelboards serving the same patient care vicinity is not permitted to be broken and must be continuous without a splice.
False
The bonding conductor(s) or grounding electrode conductor(s) for communications systems are not required to be run in as straight a line as practicable.
False
The copper ribbon or tape shield of a medium-voltage cable is permitted to serve as the required equipment grounding conductor for a circuit supplied by a 1,500-volt, solidly grounded system.
False
The grounding electrode conductor or bonding conductor installed for a communications system in a commercial building is required to be sized using NEC Table 250.66.
False
The two general categories of integrated circuits are the transistor-transistor logic (TTL) family and the programmable logic controller (PLC) family.
False
Where a grounding electrode conductor or bonding conductor for a radio antenna system is installed in a metal raceway, the contained grounding electrode conductor is not required to be bonded to both ends of the raceway.
False
NEC ? provides the requirements for grounding of electrical systems and equipment at buildings or structures that are supplied from a feeder(s) or branch circuit(s).
Section 250.32
Which section of Article 250 requires the electrodes present at any building or structure served to be bonded together to form a grounding electrode system?
Section 250.50
Circulating current within the grounding electrode system and over conductive parts of equipment (often referred to as ground loops) is a condition that can be created by multiple earth grounding points, containing a voltage potential between the ground points that is high enough to produce a circulating current.
True
Communications systems bonding conductors and grounding electrode conductors shall be protected where exposed to physical damage and where installed in a metal raceway. Both ends of the raceway must be bonded to the contained conductor or to the same terminal or electrode to which the bonding conductor or grounding electrode conductor is connected.
True
Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.
True
Ground detectors are required for 480-volt, 3-phase, ungrounded, delta-connected systems.
True
Ground-fault detection is required for ungrounded DC systems but permitted for grounded DC systems.
True
Ground-fault protection of equipment is not permitted for a service supplying a 480-volt fire pump supplied by a 1,200-ampere breaker.
True
Ground-fault protection of equipment is required for each branch circuit disconnect rated at 1,000 amperes or more and supplied by a 480Y/277-volt system.
True
Ground-fault protection of equipment is required to protect large equipment from arcing burn-downs and destruction caused by phase-to-ground faults.
True
Ground-fault protection of equipment provisions of 230.95 shall not apply to a service disconnect for a continuous industrial process where a non-orderly shutdown will introduce additional or increased hazards.
True
Grounding and shielding conductors can reduce unwanted electromagnetic interference (often referred to in the field as noise.)
True
In Class I, Division 2 locations, rigid metal conduit and intermediate metal conduit shall be permitted when used with listed threadless fittings.
True
In general, the grounding electrode conductor for a community antenna and radio distribution system shall be as short as practicable; no maximum length is specified other than for one- and two-family dwellings.
True
In hazardous (classified) locations, it is vital to have effective grounding and bonding to facilitate fast overcurrent protective device operation and prevent explosions.
True
In health care facilities, where ground-fault protection is provided for operation of the service disconnecting means or feeder disconnecting means as specified by 230.95 or 215.10, an additional step of ground-fault protection of equipment shall be provided in all next-level feeder disconnecting means downstream toward the load.
True
On construction sites, GFCI protection is required for 125-volt, single-phase receptacles that are not part of the permanent wiring of a building or structure.
True
Ungrounded systems are required to be marked "Caution: Ungrounded System Operating Volts Between Conductors" at the source or first disconnecting means of the system, and the marking must be of sufficient durability for the environment in which it is installed.
True
Where a building or structure is supplied by an ungrounded system, the feeder from the ungrounded system must include an equipment grounding conductor or supply-side bonding jumper with the conductors to the building disconnecting means, and it must be connected to the disconnecting means enclosure as well as to the grounding electrode conductor.
True
Where an auxiliary grounding electrode is installed for an electric sign on a pole, it shall be in addition to the required equipment grounding conductor with the branch circuit supplying the sign.
True
Where electrical systems over 1,000 volts are grounded, the applicable requirements in all of Article 250 apply to the installation, in addition to the specific requirements in 250.182 through 250.194.
True
The primary protector grounding terminal or grounding electrode shall be connected to the metal frame or available grounding terminal of the mobile home with a copper conductor not smaller than ? , where there is no mobile home service equipment or disconnecting means as in 800.106(A) or where the mobile home is supplied by cord and plug.
a. 12 AWG
Where a grounding electrode conductor is installed for an optical network terminal of a premises-powered broadband communications system, what is the minimum-size copper conductor required?
a. 14 AWG
The bonding conductor or grounding electrode conductor for fiber-optic cables and equipment shall not be smaller than ? , and the bonding conductor or grounding electrode conductor (where installed) shall not be required to exceed ? .
a. 14 AWG / 6 AWG
Where used outside, aluminum or copper-clad aluminum conductors for radio and television antenna systems shall not be installed within ? of the earth.
a. 18"
Performance requirements for grounded electrical systems are provided in ? of the NEC.
a. 250.4(A)
Which of the following is typically not a separately derived system?
a. Autotransformer with a grounded conductor common to both the primary and secondary
If a building has a metal underground water pipe electrode and an in-ground support structure for the grounding electrode system, which of the following grounding electrodes are required to be used for grounding a separately derived system?
a. Both electrodes must be used
The UL, LLC requirement for ? ground-fault circuit interrupters is that tripping shall occur when the continuous 60-hertz differential current exceeds six milliamperes, but it shall not trip at less than four milliamperes.
a. Class A
All metallic shields (ribbon tape shields or concentric stranding) are required to be directly connected to which of the following?
a. I., II., III., and IV.
? on a neutral conductor supplying a building or structure housing livestock can result in elevated levels of stray current in conductive components such as metal flooring, metal rails, and feeding troughs.
a. Inappropriate neutral-to-ground connections
The minimum size required for the grounding electrode conductor installed for an ungrounded DC system must not be smaller than required in ? .
a. Section 250.166
The grounding electrode conductor for a grounded 12,470-volt system is required to be sized using which of the following tables in the NEC?
a. Table 250.66
An area where wire mesh or other conductive elements are embedded in or placed under concrete, bonded to all metal structures and fixed nonelectrical equipment that may become energized, and connected to the electrical grounding system to minimize voltage differences within and between the planes, grounded equipment, and the earth best defines ? .
a. equipotential plane
A solar photovoltaic system that is functionally grounded is one that ? .
a. has an electrical ground reference for operational purposes and is not solidly grounded
A(n) ? is a specific grounding and bonding device that provides a means for connecting bonding conductors for communications systems to the grounding electrode system.
a. intersystem bonding termination
Where the branch circuit serving a Category 2 patient care space is a 30-ampere circuit, what is the minimum size required for an insulated copper equipment grounding conductor?
b. 10 AWG
Through-wall lighting assemblies and wet-, dry-, or no-niche luminaires are required to be connected to an insulated copper equipment grounding conductor installed with the circuit conductors sized according to Table 250.122 but no smaller than ? .
b. 12 AWG
Where a mobile home is supplied with a fiber-optic communications system and equipment, the grounding electrode shall be bonded to the metal frame or available grounding terminal of the mobile home with a copper conductor not smaller than ? .
b. 12 AWG
The bonding conductor or grounding electrode conductor for a communications system shall not be smaller than ? copper or other corrosion resistant material.
b. 14 AWG
If the ungrounded system conductors of a 4,160-volt system are sized at 4/0 AWG, what is the minimum size required for a grounding electrode conductor for the system if the grounding electrode is a 2 AWG ground ring electrode?
b. 2 AWG
What is the minimum size copper bonding jumper required for a metal water piping system (not a grounding electrode) in a building or structure supplied by a 400-ampere feeder when the largest ungrounded feeder conductor is 600 kcmil copper?
b. 3 AWG
An AC substation covered by Part X of the NEC is required to have a grounding electrode system in accordance with the requirements of ? .
b. Part III of Article 250
Where the grounded conductor for a 5-kilovolt service is installed with the ungrounded service conductors to the service disconnecting means, at a minimum, what NEC table must be used to size the grounded conductor?
b. Table 250.102(C)(1)
An intersystem bonding termination for connecting intersystem bonding conductors required for other systems shall be provided ? enclosures at the service equipment or metering equipment enclosure and at the disconnecting means for any additional buildings or structures.
b. external to
The NEC® defines the term ? as the earth.
b. ground
Where a 30-ampere branch circuit for field-installed skeleton neon tubing is installed using PVC conduit, what is the minimum-size copper equipment grounding conductor required for grounding metal parts associated with this installation?
c. 10 AWG copper
Substation metal fences located within ? of exposed conductors or equipment shall be bonded to the grounding electrode system with a wire-type bonding jumper.
c. 16'
The grounding electrode conductor for a single separately derived system in accordance with ? must be sized at a minimum in accordance with the sizes in ? , based on the circular mil area of the largest ungrounded system conductor.
c. 250.30(A)(5) / Table 250.66
Where rigid metal conduit is used as the wiring method for circuits in hazardous locations, a minimum of ? full threads must be fully engaged and made up wrenchtight where conduits enter explosion-proof equipment.
c. 5
Articles 800 and 810 require an effective bonding connection between the communications system grounding electrode and the electrical power grounding electrode system with a minimum ? conductor.
c. 6 AWG
What is the minimum size required for an equipment grounding conductor that is not an integral part of a medium-voltage cable assembly?
c. 6 AWG copper / 4 AWG aluminum
A solid copper bonding conductor no smaller than ? must be run from the pool bonding grid system to the double-insulated pool pump motor location and connected to any replacement motor that is not a double-insulated type.
c. 8 AWG
In wet procedure locations of health care facilities where interruption by a GFCI cannot be tolerated, GFCI protection is not permitted to be installed. In these instances, which type of protective equipment is required?
c. Isolated power systems in accordance with 517.160
? is the relationship between voltage, current, and resistance in an electrical circuit.
c. Ohm's law
If overcurrent protection is provided where the conductors originate at a grounded separately derived system source supplying a separate building or structure, the installation must comply with ? .
c. Section 250.32(B)(1)
Where GFPE is installed in service equipment as part of a new construction project, which of the following is not a requirement of the NEC?
c. Testing by use of the push button can be used in lieu of primary injection testing.
Where communications systems grounding electrode conductors or bonding conductors are connected to aluminum or copper busbars, the busbar must meet all but which of the following requirements?
c. The busbar shall be installed in a readily accessible location.
? is not one of the methods that can be used to reduce the resistance of the earth.
c. Using a single grounding electrode
If there is no disconnecting means or overcurrent device at the load end of the conductors supplied by a separately derived system, the system bonding jumper must beinstalled ? .
c. in the source enclosure
A clamp-on ? meter is an ammeter that can measure currents as low as a few milliamperes (mA).
c. leakage current
If the intersystem bonding termination is provided through a set of terminals securely mounted to the meter or service equipment enclosure, the terminals have to be ? .
c. listed as grounding and bonding equipment
In a service equipped with ground-fault protection of equipment that is a neutral-ground strap type, the GFPE monitors and operates when ground-fault current passes over the ? .
c. main bonding jumper
Which of the following metal parts of therapeutic tubs (hydrotherapeutic tanks) are required to be bonded together?
d. All of the above
Which of the following requires ground-fault protection of equipment to be performance tested when first installed on site?
d. All of the above
Which of the following shall be connected to an insulated copper equipment grounding conductor installed with branch circuit conductors in wiring methods as provided in 517.13(A)?
d. All of the above
Which of the following shall be directly connected to the insulated copper equipment grounding conductor of branch circuits serving patient care spaces?
d. All of the above
Impedance grounded neutral systems in which a grounding impedance, usually a resistor, limits the ground-fault current shall be permitted where which of the following conditions are met?
d. All of the above.
Bonding connections for conductors to wire mesh or conductive elements used in an equipotential bonding plane for an agricultural facility shall be made using pressure connectors made of which of the following materials?
d. Any of the above
Where not protected with a continuous metallic shield that is grounded with a conductor in accordance with 810.58, the lead-in conductors for transmitting stations shall enter buildings by which of the following methods?
d. Any of the above
Which of the following is permitted to be used as the common grounding electrode conductor for a separately derived system?
d. Any of the above
In older existing installations without EGCs at the outlets, which of the following is acceptable for receptacle replacements?
d. Any of the above is acceptable.
The identification of the equipment grounding conductor connected to the equipment grounding terminals of use of isolated ground receptacles installed in patient care spaces outside a patient care vicinity shall be installed in accordance with which of the following?
d. Shall include an equipment grounding conductor with green insulation that has one or more yellow stripes along its entire length
If a generator separately derived system has overcurrent protection provided at the generator, what NEC table is used to size the equipment grounding conductors installed with the supply conductors of the generator to the transfer equipment enclosure or first disconnecting means enclosure?
d. Table 250.122
Equipment and receptacles for sensitive electronic equipment must be grounded by an EGC run with the supply circuit conductors and must be terminated on the equipment grounding terminal bus of the panelboard and marked ? .
d. Technical Equipment Ground
An equipment grounding conductor shall be run with the phase conductors of a single-point grounded neutral system and ? .
d. all of the above
If the system bonding jumper for a separately derived system is installed at the first disconnecting means enclosure, it must connect the grounded conductor of the system to ? .
d. all of the above
The amount of resistance within a grounding electrode system is often affected by the ? .
d. all of the above
Minimizing or eliminating stray voltages in an agricultural building is accomplished by bonding the reinforcing rods and wire mesh in the concrete together with a(n) ? conductor that is insulated, covered, or bare and not smaller than ? , and then connecting these bonding conductors to metal piping systems, stanchions, and the building grounding electrode system.
d. copper / 8 AWG
A(n) ? is a device intended for the protection of personnel that functions to deenergize a circuit or portion thereof within an established period of time when a current to ground exceeds the values established for a Class A device.
d. ground-fault circuit interrupter
A(n) ? is defined as a conductor used to connect the system grounded conductor or the equipment to a grounding electrode or to a point on the grounding electrode system.
d. grounding electrode conductor
Section 517.14 requires the equipment grounding terminal buses of the normal and essential branch circuit panelboards serving the same individual patient care vicinity to be bonded together with a(n) ? conductor not smaller than 10 AWG.
d. insulated continuous copper
Wet-niche luminaires that are supplied by a flexible cord or cable shall have all their exposed non-current-carrying metal parts grounded by a(n) ? equipment grounding conductor that is an integral part of the cord or cable.
d. insulated copper
Branch circuits installed in patient care spaces of health care facilities are required to be installed in a metal raceway or using another metallic wiring method that qualifies as an EGC in accordance with 250.118, in addition to a(n) ? .
d. insulated copper equipment grounding conductor
The exposed metal frames of PV modules must be grounded and bonded with devices ? for such use.
d. listed and identified
For a separately derived system, where a busbar is used for connections of the grounding electrode conductor taps to a common grounding electrode conductor, the busbar must be at least ? .
d. long enough to accommodate all conductors required to be connected to it
One significant difference between ground-fault circuit interrupters and ground-fault protection of equipment is ? .
d. one provides protection for people, while the other provides protection for equipment
Sections 517.13(A) and 517.13(B) address grounding of receptacles and fixed electrical equipment in patient care spaces. Which of the following addresses equipment grounding conductors?
e. All of the above
Ground-fault circuit interrupter protection is available in which of the following listed types of equipment or products?
e. Any of the above
Strengthened methods of bonding are required for metal raceways in hazardous locations where the voltage to ground exceeds ? .
e. Any of the above
Surge arrester grounding conductors have to be connected to which of the following?
e. Any of the above
The bonding conductor or grounding electrode conductor for radio or television equipment shall be permitted to be which of the following materials?
e. Any of the above
Where installed in dwelling unit kitchens, all 125-volt, single-phase, 15- and 20-ampere receptacles that are installed ? shall be GFCI protected.
e. both c. and d.
Non-shielded cables are permitted for circuits up to 5,000 volts in replacement applications only and under which of the following restrictive conditions?
f. All of the above.
A(n) ? grounded electrical system is one that has a direct electrical connection to ground with no intentional impedance installed between the earth connection and the system.
solidly
The connection of the grounding electrode conductor to the grounded conductor of the separately derived system is required to be made at a different location than the system bonding jumper connection.
False
A ? is defined as the circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).
branch circuit
Where equipment such as a luminaire at a light pole base in a parking lot is supplied by a single branch circuit, an auxiliary grounding electrode is permitted to be installed, but not required.
True
If a feeder to a separate building or structure is installed in rigid metal conduit, the conduit is not permitted to serve as the required equipment grounding conductor.
False
The size of a DC system bonding jumper has to be not less than the system grounding electrode conductor based on Section 250.66.
False
According to the NEC, that which is built or constructed, other than equipment, best defines which of the following?
Structure
For a 3-phase, 3-wire, corner-grounded, separately derived system that has 500 kcmil copper ungrounded derived phase conductors, the grounded conductor must be sized not smaller than ? .
b. 500 kcmil copper
Which part of Article 250 provides the specific requirements for system grounding?
b. Part II
Which of the following locations is permitted for installing the system bonding jumper for a separately derived system (transformer type)?
b. b., e., and f.
An insulated grounded conductor of a system is required to be identified by any of the following methods except ? .
b. green insulation
A(n) ? is the connection between the grounded circuit conductor and the supply-side bonding jumper or the equipment grounding conductor, or both, at a separately derived system.
d. system bonding jumper
A high-impedance grounded neutral system rated 480 volts to 1,000 volts is only permitted under which of the following conditions?
e. None of the above
A(n) ? is a premises wiring system where power is derived from a source of electric energy or equipment other than a service. Such systems have no direct connection from circuit conductors of one system to circuit conductors of another system, other than those established through bonding or grounding connections.
a. separately derived system
Where more than one separately derived system is grounded using a common grounding electrode conductor, the common grounding electrode conductor shall be sized based at not less than ? copper or ? aluminum.
b. 3/0 AWG / 250 kcmil
If a generator has a 1,200-ampere overcurrent device installed at the generator set, a minimum size of ? is required for the EGCs installed in a parallel set of four-inch PVC conduits routed from the generator to the first system overcurrent device enclosure.
b. 3/0 AWG copper
Section 250.188 requires grounding all portable or mobile high-voltage equipment that is supplied from an AC system of greater than ? .
d. 1,000 V
Where an ungrounded system is installed ground detectors shall be installed in accordance with which of the following?
d. All of the above
If a generator supplies standby power for a separate building, a separate disconnecting means where the feeder arrives at the building or structure is not required if ? .
d. Both a. and c.
Separately derived systems supplied by transformers that have a primary voltage rating less than 1,000 volts are not required to be grounded ? .
e. all of the above
A ? includes all circuit conductors between the service equipment, the source of a separately derived system, or other power supply source, and the final branch-circuit overcurrent device.
feeder
If present, which of the following grounding electrodes must be used to form a grounding electrode system for a building or structure served by a feeder or branch circuit?
All of the above must be used
If the overcurrent protective device is located on a generator outside that supplies a separate building or structure, then the feeder is on the load side of an overcurrent device. In this case, the equipment bonding jumper (load side) with the feeder is sized based on the requirements in Section 250.102(C).
False
If the transfer switch for a generator switches the grounded (neutral) conductor, the generator has to be grounded as a separately derived system in accordance with Section 250.30(B).
False
A grounding electrode system is generally required for each building or structure served by a feeder.
True
A structure is constructed or built and does not include electrical equipment.
True
If a generator is installed on a premises wiring system, it must be grounded as a separately derived system if there is a switching action in the grounded conductor through the transfer switch.
True
If the overcurrent protective device is not located on a generator outside that supplies a separate building or structure, then the feeder is on the line side of an overcurrent device. In this case, the supply-side bonding jumper with the feeder is sized based on the requirements in 250.102(C).
True
In health care facilities, those isolated powered circuits in hazardous (classified) inhalation anesthetizing locations are required to be supplied by an isolation transformer or other ungrounded source and are not permitted to be grounded.
True
It is never Code-compliant to install a feeder to a separate building or structure without an equipment grounding conductor or supply-side bonding jumper for a new installation.
True
Systems supplying cranes that operate over combustible fibers in Class III locations are not permitted to be grounded.
True
The neutral of a high-impedance grounded neutral system is required to be fully insulated, and no equipment grounding or equipment bonding connections are permitted on the supply side of the impedance device.
True
Where a system bonding jumper for a separately derived system is a wire type, it is required to be sized using Table 250.102(C)(1) or the 12.5% rule based on the size of the largest derived ungrounded phase conductor(s) or the total circular mil (cm) area of all conductors connected to any one ungrounded phase at the source.
True
Which of the following systems is required to be grounded?
a. 120V, single-phase system
If the grounding electrode for a separate building or structure is a single ground rod as permitted in 250.53(A)(2) Exception, the largest size grounding electrode conductor required is ? , regardless of the size of the feeder supplying the building or structure served.
b. 6 AWG copper
Identify three Code-compliant methods for connecting the grounding electrode conductor taps to the common grounding electrode conductor at an accessible location.
b. I., IV., and V.
Metal water piping systems in separate buildings or structures shall be bonded to which of the following?
d. Any of the above
A separately derived system is required to be grounded in accordance with 250.30(A), and it is located 50 feet from a building structural metal electrode and 100 feet from a metal water pipe electrode. Which of the following grounding electrodes is required to be used to meet the minimum requirements in the NEC?
a. The system shall be grounded by connection to the building grounding electrode system.
The ? for an ungrounded system is required to be connected to the system as close as practicable to where the system receives its supply.
b. ground detection sensing equipment
Systems operating at 50 volts to 1,000 volts are required to be grounded under which of the following conditions?
d. Any of the above
The size of the grounding electrode conductor for a separate building or structure shall generally not be smaller than the sizes provided in ? .
a. Table 250.66, based on the size of the largest ungrounded conductor of the feeder
Where the derived phase conductors (secondary conductors) from a transformer separately derived system are sized at 500 kcmil copper and installed in flexible metal conduit from the transformer to a panelboard, what is the minimum size copper supply-side bonding jumper required to be installed in the flexible metal conduit?
c. 1/0 AWG
A separately derived system is installed and has 4/0 AWG copper conductors installed from the secondary of the system to a 225-ampere panelboard. What is the minimum-size copper bonding jumper for a metal water piping system that serves the same area served by the separately derived system?
c. 2 AWG
What size copper grounding electrode conductor is required for a separately derived system with 4/0 AWG copper ungrounded derived phase conductors if the grounding electrode is a metal building frame electrode in accordance with 250.52(A)(2)?
c. 2 AWG
The ? is 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 metal parts required to be electrically connected.
c. supply-side bonding jumper
An exception applying only to existing premises wiring systems permits the continued use of the grounded conductor for grounding at separate buildings under which of the following restrictive conditions?
d. All of the above.
Where a system is grounded, the grounded (usually neutral) conductor(s) in sizes 4 AWG and larger must be identified generally by which of the following means?
d. Any of the above
Where the grounded conductor is used for grounding in accordance with the provision of 250.32(B)(1) Exception No. 1, the size of the grounded conductor shall not be smaller than the larger of which of the following?
d. Either a. or c.
What is the minimum size required for the grounded (neutral) conductor of a separately derived system where there is no load on the neutral conductor? (Note: The system bonding jumper is not located at the source enclosure.)
d. Not smaller than the values in Table 250.102(C)(1), based on the size of the largest ungrounded derived phase conductor connected to the system
Secondary circuits for underwater lighting installed in swimming pools or spas are not permitted to be grounded under which of the following conditions?
d. a. and either b. or c.
On an ungrounded system, the occurrence of the first ground fault (not a short circuit or line-to-line fault) on the system will cause the overcurrent protective device for the service, feeder, or branch circuit to open.
False
An AC system operating at less than 50 volts is required to be grounded under which of the following conditions?
d. All of the above
The grounding electrode for a separately derived system must be one of the grounding electrodes used for the building or structure. It must be as near as practicable, preferably in the same area, and must be the nearest of either a metal water pipe electrode or a structural metal electrode, unless neither of the above electrodes is available.
False
Where a separately derived system is installed outside the building or structure it supplies, a grounding electrode connection is not required at the outdoor source location.
False
If a separately derived system has 600 kcmil copper secondary ungrounded phase conductors, what is the minimum size required for a copper, wire-type system bonding jumper?
c. 1/0 AWG
