NCCER Study Guide
What size wire is standard for 120 volt motor controls?
#14
What size wire is needed for 120v circuit 215' long with 39 amps?
#8
What size wire would be suitable for 120v circuit, 215' long, 39 amps?
#8
A turn ration thats 4000:5 with a primary of 1000, whats the secondary?
1.25* 4000/5=800, so what can 1000 be divided by to get 800.
What is the multiplier for bending conduit on 45 degrees?
1.41
What is the largest size conductor that can terminate a 20 amp receptacle?
10 awg
Turn ratio of a 3 Phase 13.8 Kv 115 to 1 whats the secondary?
120 volts* (13.8(1000)/115=120)
What is the standard output voltage of potential transformers?
120v
Voltage drop for #8 16510cmil copper 120v, 215' long with 39 amps?
13.1* Vd=2K(L)(I)/Cm)= 2(12.9)(215)(39)/16510= 13.1
Eight incandescent lighting fixtures are to be installed. Each fixture is 120 volts, with a 200 watt lamp. What is the total connected load?
13.3* I=P/E I=watts/volts 200/120=1.666 1.666(8)=13.3
What is the multiplier for bending conduit on 30 degrees?
2
The length of a copper conductor in a ground must be buried 2.5 ft with length at least?
20 ft
Mininum number of overload sensing units in a 3 phase?
3* one per phase
What is the multiplier for bending conduit on 15 degrees?
3.86
1500 kva 3 phase transformer has secondary voltage 480/277, whats the secondary full load average?
3125* 1500000/480=3125
For a straight pull, the minimum length for a pull box with two 1" conduits and one 4" conduit on one wall and two 1" conduits and one 4" conduit entering the opposite wall is?
32"* 8 times the largest raceway
The current flow of 4 resistors in parallel?
4
A 1000 KVA 3 phase transformer has a secondary voltage of 208/120. Whats the secondary full amperage?
4807* 100000/208=4807
A 90 degree stub has how many 15 degree segments?
6
Minimum spacing between ground rods?
6 foot* Code requires rod to be at least 6 foot apart. When using 8-10 foot ground rod, the best results come from having them 16-20 ft apart.
PVC conduit, Fittings and connectors range from 1/2" to?
6 inches
An angle or U-pull is made with #4 wire or larger. The distance between each raceway entry inside the box shall NOT be any less than how many times the trade diameter of the largest raceway?
6 times
There raceway entries on u pulls are multiplied by what factor?
6 times the race way
If a transformer primary has a full load of 54 amps, what the maximum setting of overcorrect protection?
65
You have a straight run of 78' of 1" conduit. How many pieces of conduit do you need to complete this run?
8 pieces
Minimum distance between a raceway in a pull box for angle points?
8 times largest raceway
In pure capacitance current leads voltage by?
90 degrees
A wet location connection is connected with>
A gasket Hub
Which of the following conductors has the least resistance?
A. #2awg B. #4awg C. #6awg D. 1/0 awg****
All of the following are common service voltages in the United States Except?
A. 120/208 B. 120/240 C. 277/480 D. 372/575*****
All of the following are common service voltages in the United States except?
A. 120/208 3 phase, 4 wire B. 120/240 single phase C. 277/480 3 phase D. 372/575 3 phase, 4 wire *******
Which of the following Types of conduit is too thin to be threaded?
A. Black iron pipe B. RMC C. IMC D. EMT***
IEC style contractor coils are marked with voltage values. (Ue) and with horsepower (or kilowatt) ratings?
A1, A2
IEC style control coils are marked with?
A1, A2
What instrument is used to measure Current?
Ammeter
A 22-16 awg wire is what color?
Black
Where is nonmetallic conduit (PVC) used?
Both above and below ground
How does a battery produce voltage?
Chemical Reaction
What Class is for not dust type or drip proof?
Class 1
Conbustible Dust is in what class and division?
Class II, Division I & II
Conbustable fibers are presented in?
Class III, Division I
conbustible fibers is in what class and division?
Class III, Division I
All power tools for construction and maintenance shall be grounded unless cords are?
Corded
A Multimeter measures?
Current, Voltage, Resistance
A sectional drawing Shows?
Cutaway View
A merger will be used to check a cable. The electrician must be sure that the circuit is ?
De-energized, and locked, tagged, and tested
Tray Width can't be the sum of the cable?
Diameter
The material between the capacitor plate in which an electric field appears?
Dielectric* Dielectric-an electrically insulation or nonconducting material considered for its electric susceptibility
What id type Use cable primarily used for?
Direct burial in the earth
The raceway not suitable to service wire exposed to severe damage?
EMT
The conductor system used to connect the system grounded conductor or the equipment to a grounded elected or to a point on the grounding elected system is a?
Electrode Conductor
Push button normally closed contacts are used to open a circuit to eliminate?
Eliminate a start
Until determined otherwise, all electrical equipment and conductors should be considered?
Engergized
Rubber Equipment has an?
Expiration Date
What do you use to connect heat trace cable to pipe?
Fiberglass Tape
What controls the speed of an induction motor?
Frequency
Fire alarms, Instruments, and control cables that has a shielded drain wire, the drain wire must be?
Grounded
Conducting object through which a direct connection to earth establishes is called?
Grounding Electrode
What is a system of grounding electrodes connected by grounding electrodes that are buried in the earth to provide lower resistance?
Grounding grid
What is the symbol for the primary side of a transformer?
H
Where should a stress cone be used?
High Voltage Termination
Why can a lead acid battery be an explosion hazard?
Hydrogen gas is produced during charge and discharge.
A lighting outlet with a circle 0 means?
Incandescent Fixture
Opposite force
Induction
A material with poor electrical properties is a good?
Insulator
Primary consideration for selecting proper rope?
Low stretch
The device used to inspect a raceway system is a?
Mandrel
What's used to inspect a raceway system?
Mandrel
What instrument is used to perform an insulation- resistance test is a ?
Megohmmeter
The Transformer coils of the primary and secondary share no electrical connection but the current flows through them due to?
Mutual Induction
Who is allowed to remove another Electricians tag of lock from any valve, switch or piece of equipment without proper documentation and approval?
NO one
EGC is used to connect and bond (Equipment Grounding Circuit)
Non-Current carrying metal parts
Insulating Tape
Nonconductive adhesive tape
THWN Conductors outer jacket is made of?
Nylon* THWN- Thermoplastic Heat and water nylon coated
The ungrounded conductor 240/120 4 wire system higher voltage to ground is what color?
Orange
What color do you mark your high leg to ground?
Orange
3 Wire push button circuit Auxillary holding couton (seal in) is wired with start button in?
Parallel
How Should power cable and signal cable be placed in same cable tray?
Place a divider between the signal cables and the power cables.
Jewelry or clothing cannot be made of ?
Polyester
The resistor alloy heating element used in a power limiting heating cables position temperature coefficient?
Positive Temperature
What is the purpose of lockout/tagout?
Prevents operation
What is the formula for calculating total resistance in a series circuit with three resistors?
RT= R1+R2+R3
Insulation on the barrel of crimp connectors for wires sized 22-16 AWG are typically colored?
Red
What happens to power factor when the load goes down?
Remains the same
When Ambiant Tempature gets warmer and?
Resistance goes down
C phase of a 3 phase from the front in relation to A,B, in a panel?
Right
What is the primary Consideration when selecting the proper rope for a cable pull?
Safety
A holding contact in a motor starter is normally connected in parallel with the ?
Start Push Button
Incoming control voltage on Start/stop?
Stop Button Normally closed
A protective device for limiting voltage (spikes) by discharging or by passing surge current is called?
Surge Protector
What is used to make a slight change in elevation in a cable tray system?
Swivel Plates
Which wire type has the highest Temperature rating?
THWN* TW-60 degrees C- 125A THW-75 degrees C- 150A THWN- 90 degrees C- 170A
How should heat shrink insulator be installed?
The insulator should be slipped over the connector and heat should be applied for a few seconds.
What is the Purpose of railroad jack stands?
To hold up reels of cable.
When a mechanical load increases on a squirrel cage induction motor?
Torque goes up and stator current goes up.
Type ____ cable is used for direct burial situations?
Type UF
Which conductor may be any color except green, green with yellow stripe, white and gray?
Ungrounded Conductor
Power is measured in?
Watts
What is produced in a conduit run by making two equal bends in opposite directions?
offset
What is the main purpose of the dynamometer?
to read pulling tension
