3rd year electric

Refer to Figure 303.04. Without knowing the size of the conductors between the wireway and Switch #3, which of the following best defines these conductors?

feeder

Loose connections in a circuit conductor cause arcing and in turn oxidation occurs at the connection. This oxidation causes the total circuit resistance to ___.

increase

Loose connections in a circuit conductor cause arcing and in turn oxidation occurs at the connection. The circuit is connected to a single load. The voltage at the load will be ___ with the poor connection in the circuit.

less

If a fault occurs at Point III in Figure 301.01, it is on the ___ side of the service.

load

If a fault occurs at Point IV in Figure 301.01, it is on the ___ side of the service.

load

Be sure the GFCI receptacles are in good working order and tested ___.

regularly

Refer to Figure 303.04. The conductors between the transformer and Switch 1 are best described as ___ conductors.

secondary

Electrical faults cause all the following types of stresses, except ___.

seismic

When conductor temperature increases, the resistance of the conductor increases. This causes the ampacity of the conductor to decrease.

True

Circuits HA-1, -4, and -11 with a neutral and circuits HA-2, -3, and -5 with a second neutral have been pulled in EMT from a 277/480-volt, 3Ø, 4W panelboard to fluorescent luminaires that have been installed in several classrooms in a school. If the wire from breaker 5 comes in contact with the wire from breaker 11, ___ will occur.

a backfeed

How does grounding prevent an electrical fault?

d. Grounding cannot prevent an electrical fault.

When conductor temperature increases, the resistance of the conductor increases. This causes the ampacity of the conductor to ___.

decrease

An arc flash hazard analysis is used to determine ___.

a. potential electrical arc flash hazards b. the required PPE c. the Arc Flash Boundary

An electrical safety program should include a section on ___.

a. procedures b. principles c. responsibility

Tags used for lockout/tagout may include ___.

a. the length of time the equipment is expected to be out of service b. the phone number of the worker who placed the tag c. the name of the worker who placed the tag

As circuit resistance ___, the time it takes for an OCPD to operate decreases.

decreases

Total opposition to the flow of electric current is called resistance in a direct current (dc) circuit and ___ in an alternating current (ac) circuit.

impedance

O'Riley's first rule for electrical installations is to make them ___.

safe

A 120-volt load is operating when you open the neutral in a j-box. If you touch the neutral from the load with your left hand and the grounded metal conduit with your right hand, your body would be in ___ with the load.

series

The maximum number of 3-pole circuit breakers used as service disconnects permitted in a 3Ø panelboard is ___.

1

If the resistance of the body is 100 ohms, how much current would pass through the body when connected to a 120-volt circuit?

1.2 amps

Each 480-volt, three-phase, wye-connected feeder disconnect with a minimum rating of ___ amperes is required to be ground-fault protected.

1000

Refer to Figure 301.02. Sealtite® (LFMC) is used between the switch and the motor. The insulation on the "hot" has been damaged and the copper is touching the motor terminal housing. How much current is "seen" by the circuit breaker? A separate grounding conductor was NOT installed in either raceway. The impedance of the Sealtite® is 500 ohms.

11.45 A

Circuits LA-1, -4, and -11 are rated at 20 amps and have a neutral. These have been run as 4-wire, 12 AWG MC cable from a 120/208-volt, 3Ø, 4W panelboard to a junction box. Fluorescent luminaires have been installed in several offices in a business and connected to these circuits. The offices will be used continuously during the business day. Each luminaire draws 1.2 amps. If no more than ___ luminaires are connected to Ckt. LA-4, the circuit breaker will operate within its ratings.

13

If ___ of current flows through a healthy human body, it can be fatal.

200 mA

The most common configuration for a grounded, three-phase, ac distribution system is four-wire, center grounded (also called "wye connected"). The code requirements for identification of a grounded conductor are provided in section ___.

200.6(A)

The Approach boundaries are viewed as a barrier extending ___ degrees around an exposed energized conductor or circuit part.

360

The Multi-Employer Worksite Policy from OSHA categorizes employers into ___ roles.

4

A 1-phase load is operating at 208 volts. If you were working on the energized equipment and touched one of the "hot" terminals with your left hand and the other "hot" terminal with your right hand, how much current would flow through your body? Your body resistance is 5 k and the equipment has an impedance of 23 .

42 mA

Which of the following conditions would be classified as an overload?

43-A noncontinuous load connected to a 40-A fuse

A 1-phase load is operating at 277 volts. If you were working on the energized equipment and touched one of the "hot" terminals with your left hand and the neutral with your right hand, how much current would flow through your body? Your body resistance is 5 K and the equipment has an impedance equal to 23 .

55.4 mA

The ___ is the distance from exposed energized conductors or circuit parts where bare skin would receive the equivalent of 1.2 cal/cm2.

Arc Flash Boundary

___ is where conductors and metal equipment are connected to establish electrical continuity and conductivity.

Bonding

___ is where conductors and metal equipment are connected together.

Bonding

An overload can be excessive current caused by a fault (short circuit or ground fault).

False

It is not required to verify that a circuit or equipment has been deenergized as long as all of the other steps of the lockout/tagout procedure have been performed.

False

Potential difference is a value measured in ohms.

False

The purpose of the grounding electrode conductor and the grounding electrode is to establish a ground-fault path to open the circuit overcurrent protective device.

False

You are going to build a restaurant on a barge that will float in Galveston Bay. The barge will be moored to a leased space in a marina. Table 250.3 is a list of additional grounding requirements. Additional Code sections that must be considered for this completed installation include ___.

I. 555.15

An effective ground-fault current path has ___.

I. continuity II. sufficient ampacity III. low impedance

During lightning strikes, electrons seek to return to ___.

I. ground (earth)

Unlike the components in a direct current (dc) circuit, the components in an alternating current (ac) circuit that affect current flow are resistance and ___.

I. inductive reactance II. capacitive reactance

Which of the following are measured in ohms

I. inductive reactance II. capacitive reactance

Impedance (Z) ___.

I. is the total opposition to current flow in a circuit II. includes resistance

Which of the following are considered to be current-carrying conductors?

I. neutral conductor II. ungrounded conductor

A ___ is an electrical fault.

I. short circuit II. ground-fault

Which of the following determines the severity of an electric shock?

I. the path taken by current through bodyII. the length of time current flowsIII. the amount of current flowing

In Figure 303.05, the grounding electrode conductor is shown at Point ___.

II

Which of the following conditions would be classified as an overcurrent?

II. an ungrounded conductor touching a grounded conductorIII. an ungrounded conductor touching a grounded metal enclosure

If you were to touch an energized ungrounded conductor and a grounded surface, ___.

II. you will be shocked

In Figure 303.05, the equipment grounding conductor is shown at Point ___.

III

Which of the following statements does NOT describe objectionable current?

Neutral current flowing over the neutral conductor

Which of the following devices is not recommended for performing absence of voltage tests?

Noncontact voltage tester

When are overcurrent protective devices (OCPDs), such as fuses, circuit breakers, and protective relays allowed to be modified?

OCPDs cannot be modified at any time

A five-wire system consists of a grounded, three-phase system and includes one insulated grounded and one insulated grounding conductor.

True

A qualified person must be trained in the skills and techniques to determine nominal voltage.

True

A solidly grounded system is one where one of the current-carrying conductors is intentionally connected to the earth.

True

A symbol for ground that is used on electrical construction drawings is correctly shown here.

True

All of the following are considered a short circuit, except for ___.

True

Although air is a good insulator, ionized air is conductive and helps to sustain arcs when an electrical arc causes the air to be ionized.

True

Because the connection is a fusion of high conductivity, Furseweld® connections can withstand repeated fault currents, and will not loosen in the way that mechanical connectors can.

True

Employers who exercise "due diligence" is an employer who is proactive with regard to safety.

True

Grounding Conductor is an NEC® definition that generally covers many different concepts and parts of a grounding system.

True

If your power tool has auxiliary handles, they must be used to keep the tool in your grip.

True

Lock-out and verify before working on or near any electrical equipment.

True

Resistance to earth is also commonly known as resistivity.

True

The human body is a good conductor because it is mostly salt water.

True

When current passes through a conductor, a magnetic field is created around the conductor. When individual circuit conductors are either in close proximity (in wireways, trenches, cable trays, etc) or contained in the same cable or conduit, these magnetic fields cancel each other because the currents in each conductor are not in phase with each other.

True

The abbreviation or symbol used for the unit of measurement for impedance is ___.

Z

The symbol used for impedance in an electrical formula is ___.

Z

Circuits HA-1, -4, and -11 with a neutral have been pulled in EMT from a 277/480-volt, 3Ø, 4W panelboard to some high-bay luminaires that have been installed in a warehouse. If the wire from breaker 4 comes in contact with the neutral, ___ will occur.

a short circuit

Which of the following is not an example of a solidly grounded system?

a. 480-volt, three-phase, three-wire

If two points in a circuit have a voltage between them but are then bonded together with a conductive jumper (a wire for example), there is essentially no longer ___ between them.

a. a difference of potential b. a voltage

A solidly grounded system is a system in which one of the circuit conductors is grounded. This conductor ___ carry current during normal circuit operations.

a. does

The NFPA 70E recommends ___ training for electrical workers.

a. instructor led classroom b. on the job

Inductive reactance is related to ___.

a. magnetic fields

One of the most important goals of the Multi-Employer Worksite Policy from OSHA is to ensure that ___.

c. good communication occurs between the contractors working on the site

Lightning ionizes the air, thus making it a good ___. This enables electrons to travel from the clouds to the earth.

conductor

The NEC® permits the grounded conductor for a 277-volt circuit to have an insulation color that is ___.

either a or b a. gray b. white

When a piece of equipment is connected to the earth, it meets the definition for ___.

grounded

The scope of Article 250 covers all of the following topics, except for ___.

grounding requirements for surge protection

NFPA 70E requires that the contract employer inform its employees of ___.

hazards the host employer has communicated to the contract employer

The sum of all three components of current opposition is referred to as ___.

impedance

Total opposition to current flow in an alternating current (ac) circuit is ___.

impedance

A written, documented electrical safety program is ___ than a verbal one.

more effective

A(n) ___ conductor carries circuit current in normal operation.

neutral

Always place your ladder on flat, stable surfaces and ___.

observe the 3-point rule

NFPA 70E requires that CPR training be certified by the employer every ___ year(s).

one

You connected the GEC to the copper main water service pipe above the ceiling. The plumber later disconnected it and has left it disconnected. Because of this, if a "hot" branch circuit conductor contacts the EGC installed with that circuit, the branch-circuit breaker will ___.

operate as it should

The point of division of line and load is located at the ___.

overcurrent devices in the service disconnecting means

The rating of a branch circuit is determined by ___.

size of overcurrent protective device

The ___ step is probably the most important step in a lockout/tagout procedure.

test for the absence of voltage

If a ground fault occurs, the branch circuit OCPD will open most quickly when ___.

the branch circuit is installed in EMT and a separate EGC has been pulled

A ground rod is the only grounding electrode at a service. If the GEC becomes loose when connected to the rod, the branch-circuit breakers in the service panel will take ___ amount of time to open if a ground fault occurs in one of the branch circuits.

the same

You should be aware of hazards created by other trades working near you.

true

You should observe "no smoking" areas near any flammable materials.

true

Potential difference refers to which of the following?

voltage

Potential difference is a value measured in ___.

volts

In terms of grounding, the earth is considered to represent ___.

zero potential