Electrician NCCER

What size wire is standard for a 120-volt motor control systems?

#14

Cable trays are usually supported by all of the following means except?

#9 wire

The sine of 0 degree is

0

An analog voltmeter is being connected to a 24 V DC circuit. Polarity is reversed. What reading will occur?

0 or fewer volts

4-inch square boxes are available with all of the following depths except?

1 inch

What is the standard length of rigid conduit?

10 FT

What is the largest size conductor that can terminate on a 20 amp receptacle

12 awg

What is the most common service use in a temporary power panel?

120/240 volt, 1-phase, 3-wire

In a AC circuit containing resistance only, _______ 12A will flow if the resistance is 10 ohms and the voltage is 120V

12A

eight incandescent lighting fixtures are to be installed. Each fixture is 120 volts, with a 200-whatt lamp what is the total connected load?

13.3 Amps

The synchronous speed at witcha 4 pole, 60 Hz induction motor operates is ________ rpm

1800

A120/208 Volt feeder consist of an 800 ft run of 500 kcmil aluminum wire in conduit. This feeder has 5% voltage drop. What will the phase-toPhase voltage be at the load end

197.60 volts

A 10-inch offset at 30 degrees is been made. What is the distance between center-to-center bends?

20 inches

A 3-phase, 4-wire, 480v service requires ________ current transformers

3

In all cases where live parts are normally exposed on the front of switchboards or motor control centers the working space in front of such equipment must be what minimum length?

3 FT

All of the following are common service voltages in the United States Except:

372/575 3-Phase, 4-wire

What maximum number of bends is allowed between fittings in one conduit run?

4 quarter bends or 360 degrees

If a voltage source of a circuit provides 240 volts and there are 5 ohms of resistance, how much current is in the circuit?

40 amps

A cable rated for 5kv insulation can safely carry what maximum voltage?

5000 volts

An angle or U-pull is made with 14 wire or larger. The distance between each raceway entry inside the box and the opposite wall of the box shall not be any less than how many times the trade diameter of the largest raceway?

6 times

What is the largest size of aluminum rigid conduit couplings?

6"

Proofs tests are made at________ oF the original factory voltage

60%

The potential across the circuits is 480 volts and the current is 50 amps. What is the resistance of the circuit?

9.6 ohms

A Transformer has 200 turns in the primary, 150 turns in the secondary, and 120VAC applied to the primary. The voltage across the secondary is

90 Volts

What is installed at a expansion joint to provide a continuous ground between 2 sections of cable tray?

A bonding jumper

The outer covering on liquid-tight flexible metal conduit is use for

A moisture seal

What is the standard wire size system used in the United States?

AWG

A switch labeled "AL-CU" can be use with what type of wire?

Aluminum Copper and copper clad aluminum

Which article of the NEC covers grounding?

Article 250

A good electrical connection should

Be mechanically and electrically secure

All of the following types of condulet may be used as a pulling point for conduit that requires a 90 degree change in direction, except_______

C

What type of conduit fitting is usually placed in the middle of a long run of rigid metal conduit to provide access for pulling wire

C

The motor type that has the highest starting torque is the _________ motor

Capacitor - start

How does a battery produce voltage?

Chemical reaction

The symbol normally use for duplex

Circle with two parallel lines draw through it

What are the 2 most common types of overcurrent protective devices?

Circuit breakers and fuses

Which of the following testing instruments operated on the current transformer principle

Clamp-on ammeter

Of the termination classes listed below,_____ is the only one that provides a seal against external elements

Class 1

When making offset bends, the two kicks must be made perfectly parallel or the resulting offset will have a ________

Crooked bend

The circular mil is based on the

Cross-sectional area of the wire

A megger will be used to check a cable. The electrician must be sure that the circuit is

De-energized and locked, tagged out, and tested

What is it important to torque bolts when busbars are connected?

Decrease resistance on the connection

Meters used in AC circuits indicate the_______

Effective

In a transformer,______

Electromagnetic induction occurs

The componente labeled 7 in figure 1 is a (an)

End seal

When a ground rod is installed, the top of the rod must be positioned _____.grade

Flush with or below

For a given number of poles, the________ determines the speed of an AC Motor.

Frequency

The number of complete AC cycles per second is called the

Frequency

Which of the following factors is used to control the speed of an induction motor?

Frequency

What color identifies and insulated, grounded, number 4 conductors?

Green

The NEC required that all receptacles installed on 25 amp and 20 amp branch circuits be__________ receptacles

Grounding

What is the symbol for the primary side of a transformer?

H

What does HOA usually mean in a motor control circuit

Hands of automatic

Where should a stress cone be used?

High voltage termination

The output capacity of a motor is rated in

Horsepower

A brass-colored terminal on a receptacle indicates that it should be used to connect what type of wire?

Hot wite

Why can a lead acid battery be an explosive hazard?

Hydrogen gas is produced during charge and discharge

Which of the following is the correct formula for OHM's law?

I=E/R

The secondary of a CT under load should not be opened because of______

Induced hight voltage

When the coil turns increased the ________

Induced voltage is increased

A 1 line diagram with simplified symbols indicates the

Interconnections and component parts of an electrical circuit

Both induction and synchronous motor operate on the principle of the rotating________field

Magnetic

What test or equipment can be use to locate suspected short circuit in 1 phase of a 3 phase motor?

Megger

What instrument is use to perform an insulation resistance test on a 480 volt motor winding?

Megohmmeter

What is a dropout plate?

Metal plate with a curve surface for cable to follow as it passes from the tray

Which type of heating cable can not be cut and terminated in the field?

Mineral insulated

Normally, the easiest place to reverse the leads to change the direction of rotation of a 3-phase motor is at the

Motor starter

Services conductors and equipment are covered in

NEC Article 230

Disconnecting means are covered in

NEC section 110-22

The __________must be grounded in a bussed glutter if use as the main service equipmemt

Neutral busbar

In relation to switches, the term throw refers to the

Number of internal operations that switch can perform

What is produced in a conduit run by making 2 equal bends in opposite direction?

Offset

What does a GFCI breaker do?

Opens a circuit to prevent operation of an electrical device

What is the purpose of lockout/Tagout?

Prevent operation

What is a seal installed in a run of conduit in a class I location?

Prevent the passage of explosive gases in the conduit

What is the primary purpose of P&ID

Provide scale drawings and piping and instrumentation control systems.

Which of the following components is part of a dual element fuse

Rejection clip

As the temperature surrounding a self regulating heating cable rises, the ________

Resistance of the polymeric core increases

Unless otherwise noted, the calculations in AC circuits ______ values

Rms

What is the primary consideration in selecting the proper rope for a cable pull?

Safety

All of the following are protective devices for motors except

Solenoid

The _____ rotor types are generally rugged

Squirrel cage

A holding contact in a motor starter is normally connected in parallel with the

Start push button

A transformer with the primary of 400 turns and a secondary of 300 turns has a

Step down turns ratio of 4:3

What is the function of a ballast on a fluorescent fixture ?

Steps up the voltage

What NEC table indicates the size of service conductors?

Table 310-16

When wall mounting cable tray, ensure that

The building structure is strong enough to support the tray system

What will happen if moisture is inside a cad-weld mold while the weld is being performed?

The cadwel mold could explode

Which of the following statements Describes the operating features of a thermal overload relay?

The greater the overload, the shorter the time of tripping

What is the interrupting rating of a fuse

The maximum value off current that the fuse is designed to interrupt.

What will happen when one or more coils in a winding are grounded?

The motor will automatically blow fuses

Service conductors are sized based on what factor?

The total calculated load of the building

What is the purpose of the thermocouple?

To measure temperature

What type of NEMA class enclosure is approved for general purpose indoor use and is NOT dust-tight or drip-proof?

Types 1

To be effective, a grounding system must limit the voltage on the electrical system and protect it from all of the following, except ______

Undervoltage conditions

What is an acceptable protection techniques for electrical equipment in hazardous location?

Use duct-ignition proof equipment

An electrical fitting can be made explosion proof in which of the following ways?

Using an amorphous sealed device

A drowning showing a point A to point B hookup of conductors is called a

Wiring diagram

What is voltage?

electromotive force

The purpose of sealing cable ends when reels of cable are in storage is ______________

to keep moisture from creeping in