Grounding level 1
When an equipment bonding jumper is installed on the outside of flexible metal conduit or liquidtight flexible metal conduit, the length of the jumper is generally limited to not exceeding ? in length.
6 feet
Auxiliary grounding electrodes are permitted to be installed for special information technology equipment covered in Article 645, and the ? must always be connected to the equipment.
EGC
Which of the following is permitted as a substitute for grounding electrical equipment?
Guarding, Insulation, Isolation
According to the NEC Style Manual, the phrase "likely to become energized" is best described by which of the following?
failure of insulation on
Equipment grounding terminal bars are required in every panelboard even if there are no wire-type equipment grounding conductors installed in the panelboard.
false
Reducing washers are not suitable for non-service bonding in circuits over and under 250 volts to ground.
false
If a conductive part is connected to ground or to a conductive body that extends a ground connection it is ? .
grounded
The supply conductors for a surge protective device are not permitted by the NEC to be smaller than ? AWG copper.
14 requirements in NEC 110.3(B).
If a metal elbow is installed in a run of PVC conduit and encased in ? of concrete, the metal elbow is not required to be grounded.
2"
Which of the following is generally not permitted to be used for grounding panelboards on the load side of the service disconnecting means?
A grounded conductor (usually the neutral
An isolated grounding-type receptacle is required to be identified by which of the following means?
An orange triangle on the receptacle
The mounting strap or yoke of a snap switch can serve as an effective ground-fault current path under which of the following conditions?
Either An EGC or equipment bonding jumper is connected to an equipment grounding termination or The switch is mounted with metal screws to a metal box or metal cover that is connected to an EGC or to a nonmetallic box with integral means for connecting to an EGC
? used for information technology equipment shall be permitted to have multiple panelboards within a single cabinet, if the power distribution unit is utilization equipment listed for information technology application
Power distribution units (PDUs)
A(n) ? is generally required to connect the grounding terminal of a grounding-type receptacle to a grounded box.
equipment bonding jumper
A(n) ? is the connection between two or more portions of the equipment grounding conductor.
equipment bonding jumper
Flexible cords with an equipment grounding conductor that have an integral insulation and jacket are permitted to be identified using the color green.
false
If a power factor correction capacitor is mounted on top of a wood pole at a height of 15 feet above ground (Earth), the capacitor case is required to be grounded.
false
Separable connections, such as those made with receptacles and attachment plugs are required to be designed and proved for a "last-make" and "first-break" connection of the equipment grounding conductor of the circuit.
false
Where installed for the reduction of electrical noise (electromagnetic interference) on the grounding circuit, an equipment enclosure supplied by a branch circuit shall be permitted to be isolated from a metal raceway containing circuits supplying only that equipment by one or more ? located at the point of attachment of the raceway to the equipment enclosure.
listed nonmetallic raceway fittings
A non-grounding-type receptacle is permitted to be replaced with another non-grounding-type receptacle only when the outlet does not include an equipment grounding conductor.
true
An EGC must be an effective ground-fault current path, even if it is an isolated/insulated EGC installed with the branch circuit.
true
An equipment bonding jumper from a metal box to a grounding-type receptacle is not necessary for a self-grounding type receptacle.
true
The purpose of a signal reference structure (grid) is to minimize potential differences between IT equipment and other conductive materials and equipment in an information technology room.
true
When a thorough building power quality analysis is performed, it should always include a thorough analysis of the building grounding and bonding system.
true
The structural metal frame of a building is permitted to be used as an equipment grounding conductor for branch circuits and feeders under controlled conditions in industrial installations only.
false
Type 1 surge protective devices are not permitted to be installed on the supply side of the service disconnect overcurrent protective device.
false Review the definitions of surge protective devices in Article 100 of the NEC. This information clarifies their uses and limitations.
If an isolated grounding-type receptacle is installed, an insulated equipment grounding conductor is required to be installed from the receptacle grounding terminal to the applicable grounding point at the service or separately derived system without connection to any panelboard or other enclosure in the circuit.
false The provisions of 250.146(D) are permissive and are not a requirement. This means that the equipment grounding conductor installed to the IG receptacle is permitted to pass through one or more panelboards or other enclosures but is not required to. For a true isolated (clean) ground, it is best, from a performance standpoint, to install the IG circuit grounding conductor with a connection only at the grounding point of the applicable service or separately derived system.
Bonding of electrical equipment is important for a grounded system because it accomplishes all but which of the following?
Eliminates voltage gradients in the Earth and provides grounding connection to the Earth. bonding is important because it establishes a connection between metal equipment, it establishes an effective ground-fault current path, it establishes conductivity between metal equipment, and it establishes continuity between metal equipment.
The grounded conductor is permitted for grounding equipment in all but which of the following locations?
In the first panelboard on the load side of the service disconnecting means
Which of the following is often a common contributor to objectionable current over the equipment grounding conductor paths in any electrical system?
Neutral-to-ground connections on the load side of the service disconnect
Which of the following is not required in order to apply Article 645 to an information technology room?
The conductive frames of IT equipment are connected to a grounding electrode that is isolated from the grounding electrode system for the service of the building. Required: a. A disconnecting means according to Section 645.10 has to be provided. b. A separate HVAC system is provided in one of the methods identified in 645.4(2) a. or c. Listed communications equipment and IT equipment are installed. d. Only equipment and wiring associated with the operation of the IT room are located in the room. f. The room is accessible to and occupied only by operators and maintainers of the equipment/system. g. The room is separated from other occupancies in the building by fire-resistant-rated construction.
Current that introduces noise or data errors in electronic equipment is considered objectionable current and remedies are provided for this condition in NEC 250.6.
false. Current that introduces noise or data errors in electronic equipment is not considered objectionable current, and remedies are provided for this condition in NEC 250.6. Refer students to Section 250.6(D).
An effective path for ground-fault current is required for the normal equipment grounding conductor (dirty ground) of a branch circuit and the isolated/insulated equipment grounding conductor (clean ground) of the circuit.
true
An equipment bonding jumper is permitted to be installed either inside or outside of a raceway or enclosure.
true
conductor (neutral) is permitted to be used for grounding under which of the following conditions?
a. Grounding contacts of receptacles furnished as part of the equipment are bonded to the equipment. b. The grounded conductor is insulated, or the grounded conductor is uninsulated and part of a Type SE service-entrance cable and the branch circuit originates at the service equipment. c. The grounded conductor is not smaller than 10 AWG copper or 8 AWG aluminum. d. The supply circuit is 120/240-volt, single-phase, 3-wire, or 208Y/120-volt derived from a 3-phase, 4-wire, wye-connected system.
A GFCI receptacle device is permitted as a replacement for a non-grounding-type receptacle under which of the following conditions?
a. No equipment grounding conductor is installed from the GFCI device to any receptacle outlet downstream. b. No equipment grounding means exists in the outlet. c. The GFCI device is marked at the outlet to indicate "No Equipment Ground."
When two conductive parts are connected together to establish electrical continuity and conductivity between them, they are ? .
bonded
A(n) ? is a reliable conductor to ensure the required electrical continuity between metal parts required to be electrically connected.
bonding conductor or jumper
An equipment grounding conductor is not required to be connected to receptacles that are installed in listed floor boxes that provide satisfactory grounding continuity.
true
If equipment is supplied by a Class 1 power-limited circuit that is grounded, the equipment is also required to be grounded.
true
Isolated grounding circuits and receptacles are installed in an effort to reduce electrical noise that can interfere with data systems and equipment.
true
Receptacles with insulating grounding terminals as described in 406.3(D) and 250.146(D) are not permitted to be installed in branch circuits serving patient care locations.
true
Resonance can occur when the frequency of an AC circuit and the length of the circuit are in tune.
true
Separate equipment grounding conductors are required for all new dryer and range circuits installed in dwelling units.
true
Standard boxes with concentric and eccentric knockouts are listed for bonding and use in circuits over and under 250 volts phase to ground.
true
The color green shall be permitted for use as the ungrounded signal conductor between the output terminals of traffic signal control equipment and the traffic signal heads where an equipment grounding conductor in accordance with 250.118 is installed or a wire-type EGC that is bare or green with one or more yellow stripes is installed.
true
The grounded conductor of each separately derived system shall be bonded to the nearest available point of the metal water piping system(s) in the area served by the separately derived system.
true
The general requirements and specific requirements for equipment grounding are provided in which part of NEC Article 250?
Part I and Part VI The question refers to both general and specific equipment grounding requirements. The general equipment grounding requirements are provided in 250.4(A)(2) and 250.4(B)(2), and the specific grounding requirements for equipment are provided in Part VI of Article 250
Where more than one raceway enters or leaves a switchboard, pull or junction box, or other equipment, it is permissible to use a single conductor to bond these raceways to the equipment where sized appropriately.
true
An aluminum equipment bonding jumper installed on the load side of a 400-ampere overcurrent device must not be smaller than ? .
1 AWG
When protected by a 40-ampere circuit breaker the must not be smaller than ? .
10 AWG copper
Which of the following is not recognized as an equipment grounding conductor in the NEC?
1/2" flexible metal conduit in lengths over 10 the NEC recognizes: a. Armor of Type AC cable b. Cable tray c. Electrical metallic tubing (EMT) d. Intermediate metal conduit (IMC) e. Rigid metal conduit (RMC)
If a submersible pump in a metal well casing is protected at 30 amperes, the equipment grounding conductor connected to the motor and the well casing must not be smaller than ? .
10 AWG copper
What is the minimum size required for an isolated/insulated equipment grounding conductor installed for a 30-ampere single receptacle on an individual circuit protected at 30 amperes?
10 AWG copper
How many equipment grounding conductor paths must be present when a design calls for installing an isolated grounding circuit and receptacle installed for computer equipment?
2
Isolated/insulated equipment grounding circuits installed in other than a patient care vicinity must include how many equipment grounding conductors to meet the requirements of the NEC?
2 Branch circuits serving patient care locations must meet the requirements in Sections 517.13(A) and (B). Section 517.16 restricts the installation of an isolated ground receptacle within a patient care vicinity. Isolated grounding receptacles installed in branch circuits serving other than a patient care vicinity must meet the requirements in 250.146(D). This requires two separate equipment grounding conductor paths be installed.
What is the minimum-size copper supply-side bonding jumper for a 600-ampere service supplied with two 400 kcmil conductors (800 kcmil is the largest ungrounded service-entrance conductor per phase) if all the conductors are in a single six-inch raceway?
2/0 AWG
What is the minimum-size copper bonding jumper required for an interconnected metal building frame if the service is rated 1,000 amperes and supplied by two parallel 600 kcmil copper conductors for each ungrounded service phase conductor?
3/0 AWG
If included in the manufacturer's instructions, Type 3 surge protective device connection shall be a minimum of ? of conductor distance from the service or separately derived service disconnect.
30'
If a 200-ampere feeder is installed from a service to a panelboard in a building and is run in PVC conduit, a minimum ? copper equipment grounding conductor is required.
6 AWG
What is the minimum-size aluminum equipment bonding jumper required for a range receptacle installed in a metal box where the branch circuit is protected by a 60-ampere circuit breaker?
8 AWG
If equipment is located more than ? vertically and ? horizontally from ground or grounded objects and not subject to contact by persons, grounding is not required.
8'/ 5' (minumum) 10'/ 6'
An isolated/insulated equipment grounding conductor is not permitted to be connected to which of the following?
A ground rod isolated from the building grounding electrode system it can be connected to: b. Grounding point at a separately derived system Incorrect c. Grounding point at the service equipment Incorrect d. Isolated equipment grounding terminal bar in a panelboard
Which of the following methods is not suitable for establishing bonding connections for circuits over 250 volts phase to ground?
A locknut on the outside and a bushing on the inside of metal enclosure
In which of the following receptacle installations is an equipment bonding jumper or conductor required to be connected from the grounded outlet box to a grounding type receptacle?
A metal box installed in a wall with drywall surface and a standard grounding receptacle is installed
Which of the following conducive parts are often used as a signal reference structure (grid) for an information technology room?
Any: a. A copper mesh system b. A grid of intersecting and interconnected flat copper strips c. The metal frame of a raised floor in an IT room
List the three elements that an effective ground-fault return path is required to perform in order to maintain and provide adequate safety.
Be electrically continuous, have sufficiently low impedance to limit the voltage to ground and to facilitate the operation of the circuit protective devices, have the capacity to conduct safely any fault current likely to be imposed on it.
The term ground loops is often used in the information technology sector and is best described by which of the following?
Circulating currents in the grounding paths
If equipment is double insulated, it must be connected to an equipment grounding conductor of the branch circuit.
False
The bonding connection for a metal water piping system is required to be readily accessible unless it is a buried connection or a connection made using the exothermic welding process.
False. There is a difference between the terms accessible and readily accessible. Section 250.104(A) does not currently offer an exception for the required accessibility for the bonding connection to a metal water pipe. This relates back to old requirements for testing and being able to disconnect this connection during testing procedures.
Which part of Article 250 provides specific electrical bonding requirements?
Part V
? requires that metal water piping and other metal piping systems installed within or attached to buildings or structures be bonded.
Section 250.104
Which of the following is not recognized in the Code as an acceptable method of attaching bonding jumpers to circuits and equipment?
Sheet metal screws and solder connections. Acceptable connections include: 1. Connections that are part of a listed assembly 2. Exothermic welding 3. Listed clamps 4. Machine screw fasteners that engage not less than two threads or are secured with a nut 5. Pressure connectors listed as grounding and bonding equipment 6. Terminal bars
Which NEC table is used to size equipment bonding jumpers on the load side of a fuse or circuit breaker?
Table 250.122
Where a building or structure is supplied by a feeder or branch circuit, the bonding jumper to the water piping system(s) is required to be sized according to ? , based on the size of the feeder or branch circuit that supplies the building or structure.
Table 250.66
Which of the following best defines the word ground?
The Earth
Where a signal reference structure (grid) is installed in an information technology room, it is required to be connected to which of the following?
The equipment grounding conductor for information technology equipment
Where a separate equipment grounding conductor is installed to a receptacle outlet that had no equipment grounding means, as permitted in Section 250.130(C), the separate equipment grounding conductor is permitted to be connected to any of the following except?
The grounded metal service riser mast
The practical safeguarding of persons and property from hazards arising from the use of electricity best describes which of the following?
The purpose of the NEC
Based on the NEC, which of the following is not permitted as a method for identifying the receptacle equipment grounding conductor connection point if the connection point is not visible?
The words "Equipment Ground"
The non-current-carrying metal parts of cord-and-plug-connected equipment, likely to be energized, are not required to be grounded by connection to the equipment grounding conductor of the branch circuit under which of the following conditions?
They are listed equipment protected by a system of double insulation and distinctively marked
Grounding equipment places equipment at or as close to Earth potential, which minimizes possible shock hazards and limits voltage to ground due to unintentional contact with higher voltage lines or due to line surges or lightning events.
True
When electrical systems or equipment are grounded, the ground (Earth) is part of the electrical circuit.
True
The Earth is not permitted as an effective ground-fault current path even if no equipment grounding conductor is installed to equipment.
True Refer students to 250.4(A)(5), 250.4(B)(4), and 250.54.
Noncoductive coatings on equipment to be grounded shall be removed from threads and other contact surfaces to ensure good electrical continuityor be connected by means of fittings designed so as to make such removal unnecessary
True 250.12
According to the NEC, which of the following are recognized methods of reducing objectionable current in the grounding system?
a. Disconnection of one or more, but not all, grounding connections or change of the location of the grounding connections c. Interruption of the continuity of the conductor or conductive path causing objectionable current d. Other remedial action approved by the authority having jurisdiction (AHJ)
Which of the following types of nonelectrical equipment are required to be grounded if likely to be energized?
a. Frames and tracks of electrically operated cranes and hoists b. Frames of non-electrically driven elevator cars to which electric conductors are attached c. Hand-operated metal shifting ropes or cables of electric elevators
Effective bonding of metal parts is required to maintain effective continuity from the service to the ?
a. farthest outlet supplied by the system b. first panelboard enclosuret c. first receptacle in the branch circuit d. first system overcurrent device
The insulated EGC connected to an isolated grounding-type receptacle is permitted to pass through one or more panelboards or other enclosures without a grounding connection as long as it terminates at the grounding point at the ? .
applicable service or separately derived system
Which of the following is a practical or typical solution for minimizing potential differences and circulating currents in information technology room installations?
b. Fiber-optic transmission over completely nonconductive paths or optical isolators c. Interface devices (surge arresters and surge protective devices) d. Installing a signal reference grid e. Modems, which are normally used as interfaces with telephone circuits f. Single-point grounding and use of a single power supply system
The metal water piping system is permitted to be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where large enough, or to one or more grounding ?
electrodes
Where loosely jointed metal raceways are used and, especially where there are expansion joints or telescoping sections of raceways, the National Electrical Code requires that they be made electrically continuous by the use of a(n) ? or other means.
eqipment bonding jumper
Where a short length of metal raceway is installed as a sleeve or for physical protection of a cable wiring method, it is required to be grounded.
false The term short section as used in the NEC is not defined, but many believe that when the length starts exceeding 10 feet (the standard length of conduit) that it is starting to get excessive and increases risks by being ungrounded dead metal.
Fittings for wiring methods such as electrical metallic tubing and rigid metal conduit are required to be ? .
listed
Surge protective devices (SPDs) covered by the requirements in the NEC are required to be ?
listed
A ? is a conductor installed on the supply side of a service or separately derived system to ensure the required electrical conductivity between metal parts required to be electrically connected
supply-side bonding jumper
A system bonding jumper is the connection between the grounded conductor and the equipment grounding conductor or ? , or both, at a separately derived system.
supply-side bonding jumper
A mounting strap of a snap switch is not required to be grounded if the switch is provided as part of a listed kit or assembly with a non-standard nonmetallic faceplate mounting means.
true
When listed Type AC cable or listed Type MC cable is installed for an isolated equipment grounding circuit, the armor of the cable assembly must qualify as an equipment grounding conductor and an insulated equipment grounding conductor must be contained within the assembly for direct connection to an IG receptacle.
true
Where concentric, eccentric, or oversized knockouts are encountered in circuits over 250 volts phase to ground, one of the bonding methods in Section 250.92(B)(2) through (4) must be applied to ensure the required continuity and conductivity.
true