Ch 7 - Service Entrance Intro
12
120/240-volt overhead service conductors must maintain a vertical clearance of at least __________ feet above the back yard of a house.
riser
A length of raceway that extends up a utility pole and encloses the service entrance conductors in an underground service is called a(n) _______________.
grounding electrode
A metal underground water pipe in contact with the earth for 20 feet must be supplemented by an additional __________________ to meet NEC requirements.
grounded
A system or circuit conductor that is intentionally grounded is called a(n) _______________ conductor.
4 AWG
According to NEC Table 250.66, the minimum size copper grounding electrode conductor for a service entrance installed with 4/0 copper conductors is__________.
250
Article _______________ of the NEC covers the grounding and bonding requirements for residential services.
1/2
Copper coated steel ground rods must be listed and be at least __________ inch in diameter.
8
Direct buried conductors emerging from the ground must be protected to a point at least __________ feet above finished grade.
8
Ground rods must be at least ________ feet long.
25 ohms
If a single grounding electrode that is a rod, pipe or plate does not have resistance to earth of ________ or less, an additional electrode must be installed.
2 to 6
One set of service entrance conductors is permitted to supply __________ service disconnecting means instead of a single main disconnect.
light fixtures
Outdoor _________ are permitted to be attached to trees.
trees
Overhead service conductors are not permitted to be attached to _______ for support.
12, 30
Service entrance cables must be supported by straps or staples within _________ inches of any electrical enclosure and at intervals not exceeding __________ inches.
10
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.
12
The NEC requires a minimum clearance of __________ feet above residential property and driveways where the voltage to ground does not exceed 300 volts.
18
The NEC requires a vertical clearance of at least __________ feet above public streets, alleys, roads, and parking areas subject to truck traffic.
grounding electrode conductor
The __________ is the conductor used to connect the grounding electrode to a system conductor or equipment.
service drop
The overhead service conductors from the last pole to the point connecting them to the service entrance conductors at the building are called __________ conductors.
triplex cable
The type of cable normally used as the service drop for a residential service entrance is called __________.
2
Underground service conductors installed as a cable assembly are required to be buried at least __________ feet by the NEC.
utility company
What group is the final authority for determining the required vertical clearances for service conductors?
20
When a ground ring is used as a grounding electrode, it must be at least a 2 AWG copper conductor at least __________ feet long.
pad-mounted transformer
A transformer designed to be mounted directly on a foundation at ground level is called a(n) ______________.
grounding electrode
A(n) __________ is a conducting object through which a direct connection to the earth is established.
neutral conductor
A(n) __________ is the conductor connected to the neutral point of a system and is intended to carry current under normal conditions.
grounded neutral
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.
rain-tight
The enclosure housing a temporary service entrance disconnecting means must be __________.
10
When a metal underground water pipe is used as a grounding electrode, it must be in contact with the earth for at least __________ feet.
12
When a warning ribbon is required to mark the location of buried underground service conductors, it must be placed at least __________ inches above the buried conductors.
8 feet
When installing service drop conductors above a residential roof, conductors must have a vertical clearance of at least __________. (General Rule)
6
Where more than one ground rod, pipe, or plate is used, the grounding electrodes must be at least __________ feet apart.
drip loop
Where service entrance conductors extend from the weatherhead, a _______________ is required to keep water from entering the weatherhead and getting into the meter enclosure.
equipment
__________ is a general term used for material, fittings, devices, appliances, lighting fixtures, apparatus, machinery, and other parts used in connection with an electrical installation.
bonding
_______________ is the term for being connected together to establish electrical continuity and conductivity.
transformer
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) _______________.
service point
The point of connection between the wiring of the electric utility and the house wiring is called the __________.