Download Electrical NCCER Study Set with 280 detailed solutions. and more Exams Electrical and Electronics Engineering in PDF only on Docsity!
detailed solutions.
Electrical NCCER Study Set with 280
detailed solutions.
Which article of the NEC covers grounding? - ANSWER article 250
Which of the following is a 90 degree, explosion proof fitting? - ANSWER Gual
What is a Metal plate with a curved surface for cable to follow as it passes from the tray? - ANSWER Dropout plate
Are not common service voltages in the United States - ANSWER 372/575 3-phase, 4-wire
Opens a circuit to prevent operation of an electrical device - ANSWER GFCI breaker
What will happen when one or more coils in a winding are grounded? - ANSWER The motor will automatically blow fuses
Eight incandescent lighting fixtures are to be installed. Each fixture is 120 volts, with a 200-watt lamp. What is the total connected load? - ANSWER 13.3 amps
The ——- must be grounded in a bussed gutter if used as the main service equipment. - ANSWER Neutral busbar
When wall mounting cable tray, ensure that the building structure is? - ANSWER Strong enough to support the tray system
The purpose of sealing cable ends when reels of cable are in storage is to - ANSWER Keep moisture from creeping in
detailed solutions.
The outer covering on liquid-tight flexible metal conduit is used for - ANSWER A moisture seal
A good electrical connection should be - ANSWER Mechanically and electrically secure
The symbol normally used for duplex - ANSWER A circle with two parallel lines drawn through it
Disconnecting means are covered in? - ANSWER NEC section 110-
In relation to switches the term throw refers to - ANSWER Number of internal operations that a switch can preform
A 3-phase, 4-wire, 480v service requires_______ current transformers. - ANSWER 3
Services conductors and equipment are covered in - ANSWER NEC article 230
The NEC requires that all receptacles installed on 25 - ANSWER Grounding
The circular mil is based on the _______. - ANSWER Cross-sectional area of the wite
The circular mil is based on the _______? - ANSWER Cross-sectional area of the wire
A transformer with the primary of 400 turns and a secondary of 300 turns has a? - ANSWER Step down turn ratio of 4:
Of the termination classes listed below,______ is the only one that provides a seal against external elements - ANSWER Class 1
Unless other wise noted, the calculations in AC circuits______ values. - ANSWER RMS (Root Mean Square)
detailed solutions.
Proofs tests are made at ________ of the original factory voltage. - ANSWER 60%
Which type of heating cable cannot be cut and terminated in the field? - ANSWER Mineral insulated
The secondary of a CT under load should not be a opened because of? - ANSWER Induce high voltage
In a transformer,_______. - ANSWER Electromagnetic induction occurs
When a ground rod is installed, the top of the rod must be positioned ________ grade. - ANSWER Flush with or below
When making offset bends, the two kicks must be made perfectly parallel or the resulting offset will have a _____. - ANSWER Crooked bend
To be effective, a grounding system must limit the voltage on the electrical system and protect it from all of the following, except______ - ANSWER undervoltage conditions
What is the most common service used in temporary power panel? - ANSWER 120/240 volt, 1-phase, 3 wire
What are the 2 most common types of over current protective devices? - ANSWER Circuit breakers and fuses
What instrument is used to perform an insulation-resistance test on a 480-volt motor winding? - ANSWER Megohmmeter
Why is a seal installed in a run of conduit in a class 1 location? - ANSWER Prevent the passage of explosive gases in the conduit
detailed solutions.
Testing instrument operated on the current transformer principle? - ANSWER Clamp on ammeter
A drawing showing a point A to point B hookup of conductors is called a? - ANSWER Wiring diagram
What does HOA usually mean in a motor control circuit? - ANSWER Hands off automatic
What is voltage - ANSWER Electromagnetic force
What is the standard wire size system used in the united states - ANSWER AWG (American Wire Gauge)
A switch labeled AC-CU can be used with what type of wire - ANSWER Aluminum copper of copper clad aluminum
What type of conduit fitting is usually placed in the middle of a long run of rigid natal conduit to provide access for pulling wire - ANSWER C
What is the largest size of aluminum rigid conduit couplings - ANSWER 6"
What is the purpose of a thermocouple - ANSWER To measure temperature
A brass colored terminal on a receptacle indicates that it should be used to connect what type of wire. - ANSWER Hot wire
What is the standard length of rigid conduit? - ANSWER 10ft
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 then how many times the trade diameter of the largest raceway? - ANSWER 6 times
detailed solutions.
An electrical fitting can be made explosion proof in which of the following ways? - ANSWER Using an amorphous sealed device
A merger will be used to check a cable. The electrician must be sure that the circuit is - ANSWER de- energized and locked and tagged out and tested
What is the function of a ballast in a fluorescent fixture - ANSWER Steps up the voltage
What is the primary purpose of P&ID - ANSWER Provides scale drawings and piping and instrumentation control systems
Which of the following factors is used to control the speed of an induction motor? - ANSWER Frequancy
A 10 inch offset at 30 degrees is being made. What is the distance between center to center bends? - ANSWER 20 inches
What is the acceptable protection techniques for electrical equipment in hazardous locations? - ANSWER Use duct-ignition proof equipment
What is the purpose of lock out tag out - ANSWER Prevents operation
What test or equipment can be used to locate a suspected short circuit in phase of a 3-phase motor? - ANSWER Megger
A 1 line diagram with simplified symbols indicates the - ANSWER Interconnections and component parts of an electrical circuit
What will happen if moisture is inside a Caldwel mold while the weld is being performed - ANSWER The Caldwel's mold could explode
detailed solutions.
What is produced in a conduit run by making equal bends in opposite direction? - ANSWER Offset
Cable trays are usually supported by all the following means expcept? - ANSWER #9 wire
4-inch square boxes are available with all of the following depths expcept? - ANSWER 1 inch
What is installed at an expansion joint to provide a continuous ground between 2 sections of cable tray?
What color identifies an insulated, grounded, number 4 conductors? - ANSWER Green
Why is it important to torque bolts when busbars are connected? - ANSWER Decreases resistance on the connection
All the following are protective devices for motors except - ANSWER Solenoid
Service conductors are sized based on what factor? - ANSWER The total calculated load of the building
The number of complete AC cycles per second is called the - ANSWER Frequancy
Which of the following components is part of a dual element fuse - ANSWER Rejection clip
A holding contact in a motor starter is normally connected in parallel with the - ANSWER Start push button
The potential across the circuit is 480 volts and the current is 50 amps. What is the resistance of the circuit? - ANSWER 9.6 ohms.
detailed solutions.
The installation specifications of both surface metal raceways and surface nonmetallic race ways can be found in - ANSWER NEC article 352
A dropout plate is best described as a - ANSWER Plate with a curved surface for cable to follow as it passes from the tray
The 2 basic cable tray failures under load are_____ failures? - ANSWER Side rail and rung
What is the correct combination for hooking up a 480 volt motor with 9 leads? - ANSWER L1&T1, L2&T2, L3&T3, 4&7, 5&8, 6&
What should be used on every wire pull through conduit? - ANSWER Wire lube
When should a de-oxide compound be used? - ANSWER During an aluminum to copper connection
To properly install a compression lug on a conductor required multiple crimps, the electrician will crimp?
- ANSWER Starting from the lug eye to the barrel opening
All of the following are standerd fuse sizes except - ANSWER 550 amp
What type of circuit breaker was developed to meet the needs to the systems where high potential fault-currents are present? - ANSWER Current limiting
Where are the overload heaters normally located in a motor circuit? - ANSWER In the motor starter between the T leads and the contractors
A heat trace cable is installed on a line that will be insulated. When will the cable be megged? - ANSWER Before and after the insulation is put on the line
detailed solutions.
Voltage has been stepped down in a transformer. What happens to the current int the secondary? - ANSWER It decreases
The standard unit for measuring the cross-sectional area of wire is the - ANSWER Circular mil
________ are intended for the electrical protection of personnel. - ANSWER GFCI
A VOM measures? - ANSWER Ohms amps volts
A type ______ conduit body has a treaded straight hub on each end and another threaded hub perpendicular to these two - ANSWER T
The test leads of a megger should never be touched when it is in use because? - ANSWER The generator voltage is present on the test leads and could result in electrical shock
The purpose of an insulated bushing at raceway termination points is to - ANSWER Protect the conductors from being damaged
Solid bottom cable tray with solid metal covers may be used in - ANSWER Environments airways excluding ducts and plenum for environmental air
The indication provided by a voltage tester represents? - ANSWER That there is a potential difference between 2 points
A volt meter is connected in? - ANSWER Parallel with the circuit
According to ohms law the amount of current in a circuit is equal to the? - ANSWER Voltage divided by the resistance
detailed solutions.
Receptacles are rated according to the - ANSWER Voltage and amperage capacity
What color wire is connected to the silver screw in an incandescent fixture - ANSWER White
What is the NEC requirement for labeling disconnects? - ANSWER All disconnects devices for circuits feeder and equipment must be clearly and permanently mark
A 3 way switch, is what type of switch - ANSWER SPDT
The relationship of a transformer primary winding to the secondary winding is expressed in - ANSWER Turns ratio
The number of complete AC cycles per second is called? - ANSWER Frequancy
The value indicated on a meter for an AC circuit are defined as root-mean-square what is another term for this? - ANSWER Effective value
In a sine wave, the number of times per second an identical pattern itself is known as - ANSWER Frequency of a waveform
What does frame size provide information about? - ANSWER Proper bolt-up
What is the voltage ratio for dual-voltage motors? - ANSWER 2 to 1
All parts of metal cable tray must be bonded together and? - ANSWER Grounded
The first step in making an exothermic cadweld connection is? - ANSWER The prepare the cable, mold, and welding material
detailed solutions.
Which of the following describes the grounding of metal parts that do not carry in a distribution system?
- ANSWER Equipment grounding
Which of the following statements is true about cadweld molds is true? - ANSWER Cadweld molds are sized to fit the cable that is being welded
Where is non metallic conduit used? - ANSWER Both below and above ground
What item is used to make a 90 degree bend when pulling wire in a cable tray? - ANSWER Cable Roller
Which of the following determines the pulling force applied to the cable when using a tigger? - ANSWER The number of wraps on the tigger drum
A conduit piston is used for what application? - ANSWER Cleaning the conduit
What is used for high tension wire pulls? - ANSWER Nylon
A section of cable tray that makes 2 vertical 90 degree turns is known as? - ANSWER A vertical T
When a cable tray system must be protected from sunlight which is true? - ANSWER Cable tray covers?
What is the maximum voltage of conductors on which wire nuts may be used for interior wiring? - ANSWER 600 volts
The terminations on a motor starter are tightened incorrectly what may happen - ANSWER It will create an ARC and increase the amperage the motor is pulling>
How is metering-of electricity accomplished for services rated greater 400 amps? - ANSWER By using a CT metering
detailed solutions.
How is a transformer rated for power output? - ANSWER volt-ampere
Which of the following is the most severe hazardous classification? - ANSWER Class 1, division 1
Which of the following types of raceways are approved for use in class 1 division 1 hazardous locations?
- ANSWER Rigid metal conduit
Which of the following would be found in a class 1 locations - ANSWER Three threads on conduit connections
Heat trace cable should never cross itself except? - ANSWER When cable is temperature self limited
To slightly change elevation of a cable tray - ANSWER Swivel plates
When climbing a scaffold you need? - ANSWER Yo yo
When you double resistance and amperage, what happens to the current? - ANSWER It stays the same
Which of the following should be used to cool dry transformers? - ANSWER Fans
Which of the following statements are true about intrinsically safe euipment? - ANSWER Such equipment can be used in hazardous locations
Who is allowed to remove another electricians tag of lock from any valve, or piece of equipment without proper documentation and approval? - ANSWER No one
The minimum acceptable DC megohms resistance of a 4160 volt motor is approximately? - ANSWER 4. megohms
detailed solutions.
The drawing scale is (most) likely to be found in which of the following drawing locations? - ANSWER The drawing title book
Which of the following statements about a service neutral conductor is true? - ANSWER It may be smaller than the ungrounded conductors, should be larger then the underground conductors
What types of conduit can be safely used in a corrosive environment? - ANSWER Galvanized steel and plastic coating
The leads on a type k thermocouple are - ANSWER Yellow and red
What does thermal overload protect in a starter or MCC - ANSWER Motors
What is the minimum headroom at service equipment - ANSWER 6ft 6in or 7 ft
How are primary leads identified in a transformer? - ANSWER H1,H2,H
What color identifies an insulated, grounded, number 4 conductor? - ANSWER White/green
Not a standerd fuse size? - ANSWER 550 or 601
What type of circuit breaker was developed to meet the needs of modern power systems where high potential fault current are present? - ANSWER Current limiting breakers
Where are the overload heaters normally located in a motor circuit? - ANSWER In the motor starter between the T leads and contactor
detailed solutions.
All of the following information is found on a one line diagram of a substation except? - ANSWER The scale
What are three elements in every electrical circuit? - ANSWER Power source wire and load
Chico sealing compound is to be applied in an EYD fitting, the electrician must make sure that? - ANSWER The drain remains clear
The point of attachment of service drop conductors must provide minimum clearance as specified in what NEC table? - ANSWER 230-
Which of the following components is part of a dual elemant fuse? - ANSWER Time delay
A holding contact in a motor starter normally connected in parrallel with - ANSWER The start push button
The color of the outer finish required to mark a phase busbar or the conductor having the higher voltage to ground is? - ANSWER Orange
When splicing small size stranded conductors using crimp type connectors _______ may be a problem? - ANSWER Lost strands
A sectional drawing is a? - ANSWER A cutaway view of a building or object
Utility metering equipment is used to _____ of an electrical service? - ANSWER Measure the power consumption
Where several conductors are pulled together, they should be arranged_____ on the fish tape - ANSWER Staggered
detailed solutions.
Of the 16 usual divisions found in written specifications, division_____ deals mainly with electrical work?
Before a splice or connection can be make to type THHN conductor, the _____? - ANSWER Conductor ends must be stripped and cleaned
The device used to prevent the passage of gases vapors and flames through a conduit is a? - ANSWER Sealing fitting?
To strip insulation when splicing wire ______ should be used? - ANSWER Wire strippers
The type and size of overcurrent protection may be found in the - ANSWER Panel board schedule
The requirements and proper application of boxes and fittings can be found in - ANSWER NEC section 300-
After a hazard review is completed,______ determines the classification of a confined space as a non permit or remit require confined space - ANSWER The supervisor and project saftey managers
When busbars are secured to withstand the torque created by the available amount of short circuit current they are said to be? - ANSWER Braced
Specific data for a hazardous material is found in? - ANSWER The MSDS
Rod, pipe, and electrodes must have a resistance to ground of ______ ohms or less. - ANSWER 25
A grounding electrode conductor must be connected _____ of a main distribution panel. - ANSWER To the neutral terminal bus
