ch 7

Question 1

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.

Answer 1

supply-side bonding jumper

Question 2

A(n) ? is the connection between two or more portions of the equipment grounding conductor.

Answer 2

equipment bonding jumper

Question 3

When two conductive parts are connected together to establish electrical continuity and conductivity between them, they are ? .

Answer 3

bonded

Question 4

A system bonding jumper is the connection between the grounded conductor and the equipment grounding conductor or ? , or both, at a separately derived system.

Answer 4

supply-side bonding jumper

Question 5

Bonding of electrical equipment is important for a grounded system because it accomplishes all but which of the following?

Answer 5

It eliminates voltage gradients in the Earth

It establishes continuity between metal equipment.

Question 6

List the three elements that an effective ground-fault return path is required to perform in order to maintain and provide adequate safety.

Answer 6

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.

Question 7

Which of the following is recognized in the Code as an acceptable method of attaching bonding jumpers to circuits and equipment?

Answer 7

Connections that are part of a listed assembly

Exothermic welding

Listed clamps

Machine screw fasteners that engage not less than two threads or are secured with a nut

Pressure connectors listed as grounding and bonding equipment

Terminal bars

Question 8

According to the NEC Style Manual, the phrase “likely to become energized” is best described by which of the following?

Answer 8

Failure of insulation on

Question 9

Which part of Article 250 provides specific electrical bonding requirements?

Answer 9

part V

Note: Mention the general performance requirements for bonding in Sections 250.4(A)(3) and (4) and 250.4(B)(2) and (3). The question asks for specific bonding requirements. These are the general performance criteria on which the specific (prescriptive) rules are based.

Question 10

Fittings for wiring methods such as electrical metallic tubing and rigid metal conduit are required to be ? .

Answer 10

listed

Question 11

Effective bonding of metal parts is required to maintain effective continuity from the service to the ? .

Answer 11

farthest outlet supplied by the system

first panelboard enclosure

first receptacle in the branch circuit

first system overcurrent device

Question 12

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) ? unless the fitting is listed for use without a field inspected equipment bonding jumper.

Answer 12

equipment bonding jumper

Question 13

Reducing washers are not suitable for non-service bonding in circuits over and under 250 volts to ground.

Answer 13

false

Question 14

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.

Answer 14

true

Question 15

Which of the following methods is not suitable for establishing bonding connections for circuits over 250 volts phase to ground?

Answer 15

A locknut on the outside and a bushing on the inside of metal enclosure

Question 16

Standard boxes with concentric and eccentric knockouts that are listed as suitable for bonding can be used in circuits over and under 250 volts phase-to-ground.

Answer 16

true

Question 17

Nonconductive coatings on equipment to be grounded shall be removed from threads and other contact surfaces to ensure good electrical continuity or be connected by means of fittings designed so as to make such removal unnecessary.

Answer 17

true

250.12

Question 18

An aluminum equipment bonding jumper installed on the load side of a 400-ampere overcurrent device must not be smaller than ? .

Answer 18

1 awg

Question 19

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?

Answer 19

2/0 awg

Question 20

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.

Answer 20

true

Question 21

A(n) ? is generally required to connect the grounding terminal of a grounding-type receptacle to a grounded box.

Answer 21

equipment bonding jumper

Question 22

Which NEC table is used to size equipment bonding jumpers on the load side of a fuse or circuit breaker?

Answer 22

Table 250.122

Question 23

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?

Answer 23

8 awg

Question 24

An equipment bonding jumper from a metal box to a grounding-type receptacle is not necessary for a self-grounding type receptacle.

Answer 24

true

Question 25

? requires that metal water piping systems and other metal piping systems installed within or attached to buildings or structures be bonded.

Answer 25

Section 250.104

Question 26

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 ? .

Answer 26

electrodes

Question 27

What is the minimum-size copper bonding jumper required for an interconnected exposed structural metal if the service is rated 1,000 amperes and supplied by two parallel 600 kcmil copper conductors for each ungrounded service phase conductor?

Answer 27

3/0 AWG

Question 28

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.

Answer 28

false

Explain that there is a difference between the terms accessible and readily accessible. The other factor in this question is the fact that 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.

Question 29

Where a building or structure is supplied by a feeder or branch circuit, the bonding jumper to the metal 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.

Answer 29

Table 250.102(C)(1)

Question 30

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.

Answer 30

true

Question 31

An equipment bonding jumper is permitted to be installed either inside or outside of a raceway or enclosure.

Answer 31

true

Question 32

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.

Answer 32

6 feet

Question 33

Where a feeder supplies a separate building or structure, and a metal frame of that structure must be bonded, what NEC table is used to size the bonding jumper?

Answer 33

Table 250.102(C)(1)

Question 34

When a gas furnace is supplied by a 30-ampere branch circuit, what is the minimum size bonding conductor or jumper required for bonding the metal gas piping system?

Answer 34

10 AWG copper

Refer students to 250.104(B), where the bonding for the gas piping system can be accomplished using the branch circuit equipment grounding conductor for the circuit supplying the equipment. Also point out that Informational Note No. 2 refers users to additional bonding requirements that are provided in Section 7.13 of NFPA 54, National Fuel Gas Code. The question asks for the minimum, and the type of gas piping system is not provided in the question.

Question 35

Referring to the drawing, what is the minimum size required for the copper supply-side bonding jumper in this service?

Answer 35

2 AWG

Question 36

Referring to the drawing, what is the minimum size required for the copper supply-side bonding jumper in this service and what is the minimum size required for a copper load-side bonding jumper?

Answer 36

2 AWG / 4 AWG

Question 37

Which of the following tables is used to size bonding conductors or jumpers for interior metal water piping systems?

Answer 37

Table 250.102(C)(1)

Question 38

What is the minimum size copper bonding conductor for an interior metal water piping system if the building is supplied by a service that has a large ungrounded service entrance conductor size of 2,500 kcmil?

Answer 38

350 kcmil

Note: 2,500 kcmil x 12.5% = 312,500 kcmil round up to the next standard available size is 350 kcmil based on Table 8, Chapter 9 and Table 250.102(C)(1).

Question 39

The largest size bonding jumper or conductor for interconnected exposed structural metal building frames is 3/0 copper or 250 aluminum.

Answer 39

false

Note: The NEC now requires interior metal water piping systems and exposed interconnected structural metal building framing to be bonded with conductors or jumpers not smaller than the sizes in Table 250.102(C)(1).

Question 40

Bonding wedges are suitable for use to accomplish the bonding required by 250.92(B)(2) through (4).

Answer 40

true