Deck 7: Introduction to Residential Service Entrances

Question 1

One set of service entrance conductors is permitted to supply __________ service disconnecting means instead of a single main disconnect.

A) 2 to 4
B) 2 to 6
C) 3 to 6
D) 3 to 5

Answer 1

B

Question 2

A metal underground water pipe in contact with the earth for 20 feet is permitted to be the only grounding electrode needed to meet NEC requirements.

Answer 2

False

Question 3

When a metal underground water pipe is used as a grounding electrode, it must be in contact with the earth for at least __________ feet.

A) 5
B) 8
C) 10
D) 12

Answer 3

C

Question 4

When installing service drop conductors above a residential roof, conductors must have a vertical clearance of at least __________. (General Rule)

A) 3 feet
B) 5 feet
C) 8 feet
D) 10 feet

Question 5

If a single grounding electrode that is a rod, pipe or plate does not have resistance to earth of 25 ohms or less, an additional electrode must be installed.

Question 6

What group is the final authority for determining the required vertical clearances for service conductors?

A) Underwriters Laboratories
B) National Electrical Code
C) National Electrical Manufacturers Association
D) Utility Company

Question 7

The point of connection between the wiring of the electric utility and the house wiring is called the __________.

A) service drop
B) service lateral
C) service point
D) service conductors

Question 8

__________ is a general term used for material, fittings, devices, appliances, lighting fixtures, apparatus, machinery, and other parts used in connection with an electrical installation.

A) Circuit
B) Equipment
C) Enclosure
D) Electrode

Question 9

Overhead service conductors are permitted to be attached to trees for support.

Question 10

When a ground ring is used as a grounding electrode, it must be at least a 2 AWG copper conductor at least __________ feet long.

A) 15
B) 20
C) 30
D) 50

Question 11

The overhead service conductors from the last pole to the point connecting them to the service entrance conductors at the building are called __________ conductors.

A) service drop
B) riser
C) service lateral
D) None of the above

Question 12

The NEC requires a clearance of at least __________ feet above final grade for service conductors where they are connected to the building, above sidewalks and other areas accessible to pedestrians.

A) 18
B) 12
C) 10
D) 8

Question 13

Outdoor light fixtures are permitted to be attached to trees.

Question 14

Service entrance cables must be supported by straps or staples within __________ inches of any electrical enclosure and at intervals not exceeding __________ inches.

A) 8, 24
B) 12, 24
C) 8, 30
D) 12, 30

Question 15

The enclosure housing a temporary service entrance disconnecting means must be dust-tight.

Question 16

The NEC requires a vertical clearance of at least __________ feet above public streets, alleys, roads, and parking areas subject to truck traffic.

A) 10
B) 12
C) 15
D) 18

Question 17

Direct buried conductors emerging from the ground must be protected to a point at least __________ feet above finished grade.

A) 1.5
B) 2.5
C) 5
D) 8

Question 18

Underground service conductors installed as a cable assembly are required to be buried at least __________ feet by the NEC.

A) 1
B) 2
C) 3
D) 4

Question 19

When a warning ribbon is required to mark the location of buried underground service conductors, it must be placed at least __________ above the buried conductors.

A) 12"
B) 8"
C) 18"
D) 24"

Question 20

The NEC requires a minimum clearance of __________ feet above residential property and driveways where the voltage to ground does not exceed 300 volts.

A) 18
B) 10
C) 15
D) None of the above

Question 21

Explain why a seal is required anytime a raceway containing electrical conductors is installed from a cold area to a warm area.

Question 22

Ground rods must be at least ________ feet long.

A) 6
B) 8
C) 10
D) 12

Question 23

Where more than one ground rod, pipe, or plate is used, the grounding electrodes must be at least __________ feet apart.

A) 4
B) 8
C) 10
D) None of the above

Question 24

A(n) __________ is a conducting object through which a direct connection to the earth is established.

A) bond wire
B) grounding electrode
C) main bonding jumper
D) grounded conductor

Question 25

A length of raceway that extends up a utility pole and encloses the service entrance conductors in an underground service is called a(n) _______________.

Question 26

A(n) __________ is the conductor connected to the neutral point of a system and is intended to carry current under normal conditions.

A) grounding conductor
B) ungrounded conductor
C) service conductor
D) neutral conductor

Question 27

Where service entrance conductors extend from the weatherhead, a _______________ is required to keep water from entering the weatherhead and getting into the meter enclosure.

Question 28

A piece of electrical equipment used by the utility company to step down the high voltage of the utility system to the 120/240 volts required for a residential electrical system is called a(n) _______________.

Question 29

_______________ is the term for being connected together to establish electrical continuity and conductivity.

Question 30

A system or circuit conductor that is intentionally grounded is called a(n) _______________ conductor.

Question 31

Copper coated steel ground rods must be listed and be at least __________ in diameter.

A) 1/2"
B) 5/8"
C) 3/4"
D) 1"

Question 32

120/240-volt overhead service conductors must maintain a vertical clearance of at least __________ feet above the back yard of a house.

A) 10
B) 12
C) 15
D) 18

Question 33

When bonding together the noncurrent carrying metal parts of a service entrance, which of the following methods may be used?

A) exothermic welding
B) listed pressure connectors
C) listed clamps
D) all of the above

Question 34

A transformer designed to be mounted directly on a foundation at ground level is called a(n) ____________________________.

Question 35

A ground rod cannot be driven completely into the ground because of large rocks in the soil. Explain what options you have to meet NEC requirements.

Question 36

The _______________ conductor of an AC service is connected to a grounding electrode system to limit the voltage to ground from lightning, line surges, and unintentional high voltage crossovers, and to stabilize the voltage to ground during normal operation.

Question 37

According to NEC Table 250.66, the minimum size copper grounding electrode conductor for a service entrance installed with 4/0 copper conductors is__________.

A) 8 AWG
B) 6 AWG
C) 4 AWG
D) 2 AWG

Question 38

Article _______________ of the NEC covers the grounding and bonding requirements for residential services.

Question 39

The __________ is the conductor used to connect the grounding electrode to a system conductor or equipment.

A) grounding electrode conductor
B) grounding conductor
C) neutral conductor
D) service conductor

Question 40

The type of cable normally used as the service drop for a residential service entrance is called __________.

A) quadplex cable
B) Romex
C) triplex cable
D) UF cable

Question 41

Explain why the NEC and local utility companies require the service entrance disconnecting means, if located inside a house, to be installed as close as possible to where the service conductors enter the house.