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48 Cards in this Set

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Purpose of the nec

This is described as the practical safeguarding of persons and property from using electricity

If a conductive part is connected to ground or to a conductive body that extends a ground connection, it is what?

Grounded

In one word, define ground

Earth

The connection to earth through which grounding is accomplished is provided by what?

Grounding electrode

This minimizes potential differences between conductive parts that are bonded together. It also safeguards against shock hazards and in many cases ensures an effective path for ground-fault current

Bonding

The process of this and this work simultaneously to reduce potential differences between conductive parts and the earth, thereby reducing shock hazards

Grounding and bonding

This occurs when electrical current in a circuit returns through the equipment grounding conductor, through conductive material other than the electrical system ground, through a person, or through a combinatiom of these ground return paths

Ground fault

Grounding includes two basic concepts, grounding of what two things

Equipment and system

Opposition to an AC circuit is what?

Impedance

The frame of an automobile is typically what of the electrical system?

Negative side of the battery

This is the electromotive force of a circuit

Voltage

For current to be present in electrical circuits, including grounding and bonding circuits, the circuit must be what?

Complete

In its simplest form, this is two conductors separated by insulation

Capacitor

This is the maximum current a system is capable of delivering at anypoint on the wiring installation.

Available fault current

This is an unintentional conducting connection between two ungrounded conductors of a circuit.

Short circuit

There are three common causes of conductor insulation failure. Name two

Heat, moisture, excessive voltage stress

This organization developed the formulas to determine insulated conductor current withstand ratings.

Insulated cable engineers association


ICEA

Wire-type equipment grounding conductors expressed in table 250.122 of the NEC are approximately what percentage of the circuit conductor size?

25%

What instrument best determines the intergrity of conductor insulation?

Megohmmeter

This is defined as an electricitt conductive path from the point of a ground fault on a wiring system through normally non-current carrying conductors, equipment or the earth to the electrical supply source?

Ground- fault current path

This is the foundation of an electrical system?

Grounding electrode system

These chapters in the NEC apply generally

1 through 4

Who has the responsibility for approval of electrical installations and systems and interpreting NEC rules?

AHJ

This is a reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected.

Bonding conductor or jumper

The NEC is made up of an introductuon and how many chapters?

9

Green wire is not permitted to be used to identify what?

Grounded conductor

How many equipment grounding conductors are required to be installed with branch circuits serving patient care locations?

2

If a term is used in more than two articles in the NEC, it qualifies for inclusion where in the NEC?

Article 100

What part of article 250 specifically applies to grounding systems and circuit over 1,000 volts?

Part X

This provides the essential function of connecting the electrical system or electrical equipment to the earth

Grounding electrode

Underground metal gas piping is not permitted to be used as what?

Grounding electrode

A concrete-encased electrode can be installed in either a vertical or horizontal orientation and it must have not less than how many feet in direct contact with the earth?

20 feet

The NEC makes it clear that if any grounding electrodes are present at a building or structure served by electrical power, the electrodes must be what?

Bonded together

A grounding ring electrode must completely encircle a building or structure, be not less than 20 feet in length and must be buried not less than how many inches below the grade?

30 inches

Stainless steel rod electrodes that are listed must not have a diameter less than what?

1/2 inch

A plate electrode is required to have not less than how much of its surface in direct contact with the earth?

2 square feet

A rod or pipe electrode is generally requiree to be driven to a depth of not less than what?

8 feet

What is the maximum resistance to a ground permitted for a grounding electrode system consisting of a concrete-encased electrode, building steel electrode and metal water pipe electrodes?

There is no maximum resistance value

A distance of not less than how far should be maintained between an 8-foot ground rod and the next closest ground rod?

6 feet

This is defined as the conductors and equipment for delivering electric energy from the serving utility to the wiring system of the premises served?

Service

There are four necessary conductors in the grounding and bonding scheme for a service supplied by a geounded system. Name two

Grounded conductor


Equipment grounding conductor


Main bonding jumper


Grounding electrode conductor

This conductor carries the maximum unbalanced return neutal load and serves as an effecrive ground-fault current path in ground fault conditions

Grounded neutral conductor

Where the service disconnecting means is made up of 2 to 6 disconnects in a listed assembly, how many main bonding jumpers are required within the assembly?

As many as the number of service disconnects

The NEC requires that this be provided in the grounded conductor service equipment

Disconnecting means

Grounding connections to the grounded conductor are generally not permitted on this side of the grounding point within the service equipment enclosure.

Load side

The NEC generally requires all metal enclosures and raceways for service conductors to be grounded except for metal elbows in a run of nonmetallic service raceway that are isolated from contact by persons by my less than how many inches of cover to any part of the elbow?

18 inches

These are required to be installed in services supplied by ungrounded systems

Ground detectors

The grounded conductor is required to be routed to the service equipment along with its associated what?

Ungrounded service entrance conductor