C-10 Trade 2

Question 1

When deciding where to locate an electric meter:

a. check with the owner
b. check with the building department
c. check with the utility company
d. check with the CSLB

Answer 1

c. check with the utility company

Question 2

Why is a conduit bender the best tool for bending EMT?

a. it produces a perfect bend
b. it is easier to pull than a hickey
c. it keeps the interior volume of the pipe unchanged
d. it is most portable

Answer 2

c. it keeps the interior volume of the pipe unchanged

Question 3

When troubleshooting a living room circuit, you observe that one light will not go on but another is brighter than normal. What might be the problem?

a. a short
b. an open hot wire
c. an open neutral
d. high ground resistance at panel

Answer 3

a. a short

Question 4

If a fire detection sensor is to be wired to a control panel, it must be approved by:

a. the fire department
b. the manufacturer’s specifications
c. the authority having jurisdiction
d. the NEC

Answer 4

c. the authority having jurisdiction

Question 5

What is not true of electrical equipment rated for hazardous locations?

a. arcs or sparks are contained within a rated housing
b. conduit seals limit an explosion to near the source
c. only cool gases are allowed to escape from an electrical explosion and into the hazardous location
d. an explosion will not occur inside rated equipment

Answer 5

d. an explosion will not occur inside rated equipment

Question 6

What is the daily cost for a 600-watt appliance that runs 5 hours a day at $0.14 per kWh?

a. $0.48
b. $0.42
c. $0.70
d. $1.40

Answer 6

b. $0.42

Question 7

A building has a 120/208 V wiring system and requires a 400-amp service. A 480 V power line is available. What size and type of transformer is needed?

a. 480 V, 400-amp, 1.73:1 delta-wye with 120 V center taps
b. 480 V, 100 amp in, 1:4 delta with neutral leg
c. 480 V, 100-amp in, wye-connected 4:1 step-down
d. 480/208 V, 400-amp in, 120 T-tap delta step-down

Answer 7

c. 480 V, 100-amp in, wye-connected 4:1 step-down

Question 8

Exterior connectors used on conduit are:

a. waterproof
b. water-resistant
c. either water-resistant or waterproof
d. galvanized

Answer 8

c. either water-resistant or waterproof

Question 9

What type of light can be mounted on the wall in a closet?

a. ceramic keyless
b. fluorescent
c. open incandescent
d. partly closed incandescent

Answer 9

b. fluorescent

Question 10

The allowed wire fill in a nipple is usually:

a. 20%
b. 60%
c. 75%
d. 90%

Answer 10

b. 60%

Question 11

If a lighting circuit has two three-way switches in the black line and you are asked to add another switch, into which circuit leg would you tap a four-way switch?

a. red
b. black
c. white
d. green

Answer 11

b. black

Question 12

Where would you not use nonmetallic sheathed cable?

a. strip mall
b. two story apartment
c. house remodel
d. five story condo

Answer 12

d. five story condo

Question 13

What is the maximum height for an office light switch?

a. 24”
b. 36”
c. 48”
d. 60”

Answer 13

c. 48”

Question 14

One wall of a living room is 20’ long and finished entirely in glass panels. The specifications call for three receptacles along this wall. What should you do?

a. use floor receptacles
b. eliminate the receptacles
c. install two receptacles at the corners of adjacent walls and eliminate the third one
d. ask the contractor to get the specs changed

Answer 14

a. use floor receptacles

Question 15

You have a three-phase motor with nine leads. How are the connections made?

a. phase I to 1,2,3; phase II to 4,5,6; phase III to 7,8,9
b. phase I to 1,7; phase II to 2,8; phase III to 3,9; wire 4,5,6 together
c. phase I to 1,2,3,4,5; phase II to 6,7; phase III to 8,9
d. phase I to 1,2,3,4,5; phase II to 6,7,8,9; phase III not connected

Answer 15

b. phase I to 1,7; phase II to 2,8; phase III to 3,9; wire 4,5,6 together

Question 16

At an excavation, an Underground Service Alert (U.S.A.) marking on the dirt with red paint or chalk indicates:

a. gas lines
b. water lines
c. telephone lines
d. electric power lines

Answer 16

d. electric power lines

Question 17

Which metal objects must be bonded when near a pool or spa?

a. ladders
b. light housings
c. base of diving board
d. all of the above

Answer 17

d. all of the above

Question 18

You need to design a 120/208-volt system for small appliances, lights, etc. What type of transformers would you use?

a. delta - delta
b. wye - delta
c. delta - wye
d. wye - wye

Answer 18

d. wye - wye

Question 19

Which parts in the following diagram can serve as part of the grounding electrode system?

a. 1, 3, 4, & 5
b. 4, 5, & 6
c. 2, 4, & 5
d. 1, 2, & 6

Answer 19

b. 4, 5, & 6

Question 20

What is the maximum rating for a garbage disposal on a 20-amp branch circuit?

a. 50%
b. 70%
c. 80%
d. 90%

Answer 20

a. 50%

Question 21

Where would a 208Y/120 V service most likely be installed?

a. single family residence
b. light industrial building
c. heavy industrial building
d. special purpose only

Answer 21

b. light industrial building

Question 22

In which location is the use of a test meter with a CAT-II 600 volt safety rating strongly recommended?

a. low energy electronics in protected office equipment
b. outlets more than 10 meters (33 ft) from service panel
c. outlets 6 meters (20 ft) from service panel
d. main service panel

Answer 22

b. outlets more than 10 meters (33 ft) from service panel

Question 23

Who schedules the next phase of work after the rough wiring is done?

a. city inspector
b. architect
c. owner
d. prime contractor

Answer 23

d. prime contractor

Question 24

What is the minimum clearance above grade, as specified in the NEC, for a service drop up to 600 volts?

a. 8’
b. 10’
c. 12’
d. 15’

Answer 24

b. 10’

Question 25

An incandescent light is supposed to be controlled by two switches. One switch can turn the light on and off, but the other switch does nothing. The owner says it has been this way since the house was built. What could be the problem?

a. reversed neutral and grounded conductors
b. reversed hot and traveler conductors
c. reversed hot and grounded conductors
d. reversed cold and hot wires

Answer 25

b. reversed hot and traveler conductors

Question 26

Which of the following substances is now regulated by Title 8?

a. concrete
b. asbestos
c. plaster board
d. electric wire

Answer 26

b. asbestos

Question 27

A bonding jumper connected to a dryer chassis for a ground should be at least:

a. No. 12
b. No. 10
c. No. 8
d. No. 6

Answer 27

b. No. 10

Question 28

The wire fill permitted at all points in an auxiliary gutter is:

a. 20%
b. 30%
c. 40%
d. 75%

Answer 28

a. 20%

_{<em>366.22 Number of Conductors. <br></br>(A) Sheet Metal Auxiliary Gutters. The sum of the cross-sectional areas of all contained conductors at any cross section of a sheet metal an auxiliary gutter shall not exceed 20 percent of the interior cross-sectional area of the sheet metal auxiliary gutter. The adjustment factors in 310.15(B)(3)(a) shall be applied only where the number of current-carrying conductors, including neutral conductors classified as current-carrying under the provisions of 310.15(B)(5), exceeds 30. Conductors for signaling circuits<br></br>or controller conductors between a motor and its starter and used only for starting duty shall not be considered as current-carrying conductors. <br></br>(B) Nonmetallic Auxiliary Gutters. The sum of cross-sectional areas of all contained conductors at any cross section of the nonmetallic auxiliary gutter shall not exceed 20 percent of the interior cross-sectional area of the nonmetallic auxiliary gutter.<br></br>366.23 Ampacity of Conductors. </em>}

Question 29

All circuits in a house are working except in one bedroom, where none of the lights or receptacles work. A neon test light indicates there is voltage between the line and ground screw. What is the problem?

a. tripped breaker
b. open circuit neutral
c. open service panel neutral
d. missing ground

Answer 29

b. open circuit neutral

Question 30

A GFCI is intended to:

a. protect people by de-energizing the circuit when the device’s rated sense threshold is exceeded
b. disconnect the circuit automatically when a pre-determined over-current is detected
c. ensure electrical ground continuity
d. ensure the integrity of electrical insulation

Answer 30

a. protect people by de-energizing the circuit when the device’s rated sense threshold is exceeded

Question 31

Which should you not use for motor overload protection?

a. single element fuse
b. dual element fuse
c. thermal relay
d. magnetic relay

Answer 31

a. single element fuse

Question 32

Sheet metal raceways must be secured every ___ along the entire length.

a. 3’
b. 4’
c. 5’
d. 6’

Answer 32

c. 5’

_{<em>376.30 Securing and Supporting. Metal wireways shall be supported in accordance with 376.30(A) and (B).<br></br>(A) Horizontal Support. Wireways shall be supported where run horizontally at each end and at intervals not to exceed 1.5 m (5 ft) or for individual lengths longer than 1.5 m (5 ft) at each end or joint, unless listed for other support intervals. The distance between supports shall not exceed 3 m (10 ft).<br></br>(B) Vertical Support. Vertical runs of wireways shall be securely supported at intervals not exceeding 4.5 m (15 ft) and shall not have more than one joint between supports. Adjoining wireway sections shall be securely fastened together to provide a rigid joint.</em>}

Question 33

The secondary of a transformer provides 240/120 V power in an older factory service drop. Where should this transformer be grounded?

a. at the A phase terminal
b. at any phase terminal
c. on the winding that provides the two 120 V legs
d. it should not be grounded

Answer 33

c. on the winding that provides the two 120 V legs

Question 34

Electrical conduits on gasoline islands must be sealed to a minimum height of:

a. 18”
b. 24”
c. 36”
d. 48”

Answer 34

d. 48”

Question 35

Class-T fuses are:

a. the same as Edison base fuses
b. time-delay fuses
c. compact, fast acting, and high interrupt rating
d. not suitable for mains

Answer 35

c. compact, fast acting, and high interrupt rating

Question 36

In fire alarm systems, the wire coming out of the alarms must be:

a. mechanically supervised
b. electronically supervised
c. manually supervised
d. unsupervised

Answer 36

b. electronically supervised

Question 37

The allowed wire fill in the side-gutter or wiring space contained inside a load center, meter, or other enclosure is:

a. 20%
b. 30%
c. 40%
d. 75%

Answer 37

c. 40%

Question 38

Who would you call for temporary power after a facility is wired?

a. the CSLB
b. local OSHA
c. the City Building Department
d. the power company

Answer 38

d. the power company

Question 39

Why would you use a dry transformer?

a. to increase potential
b. to decrease potential
c. to increase current
d. to decrease current

Answer 39

b. to decrease potential

Question 40

What size service is needed for a family residence with 5000 square feet of living area and all electric appliances?

a. 100 amps
b. 200 amps
c. 300 amps
d. 400 amps

Answer 40

b. 200 amps

Question 41

What do you do first to confirm the repair of a system?

a. power up and load the system
b. reset the breaker and check for voltage
c. with the breaker off, use an ohmmeter to test for shorts
d. use an ammeter to test for shorts

Answer 41

c. with the breaker off, use an ohmmeter to test for shorts

Question 42

Where must the disconnect for a 460 V motor be located?

a. within sight of the motor
b. within 50 feet of the motor
c. on the controller
d. Both A & B

Answer 42

d. Both A & B

Question 43

An electrician has to run wires through a cold box to get to the outside. What would he have to use on the raceway to keep the air from the lines?

a. duct seal
b. pressure fittings
c. seal-off fittings
d. electrical tape

Answer 43

c. seal-off fittings

Question 44

What section of the NEC covers wire sizes?

a. 100
b. 310
c. 500
d. 680

Answer 44

b. 310

Question 45

To penetrate a masonry wall in an old home you would use a:

a. ram jet
b. hole saw
c. stucco bit
d. core drill

Answer 45

d. core drill

Question 46

The allowed wire fill in a nipple is usually:

a. 20%
b. 60%
c. 75%
d. 00%

Answer 46

b. 60%

_{<em>Note (4) in Chapter 9 of NEC 2011:<br></br><br></br>“Where conduit or tubing nipples having a maximum length not to exceed 24 in. are installed between boxes, cabinets, and similar enclosures, the nipples shall be permitted to be filled to 60 percent of their total cross-sectional area, and 310.15(B)(3)(a) adjustment factors need not apply to this condition.”</em>}

Question 47

What is meant by a “selective system” in a panelboard?

a. the breakers detect only certain types of faults
b. a branch circuit fuse will trip before the main does
c. separate breakers are provided for many small circuits
d. separate fuses are provided for many small circuits

Answer 47

b. a branch circuit fuse will trip before the main does

Question 48

Which answer describes a Class-I hazardous location?

a. potentially explosive gases, vapors, or liquids
b. conductive and/or explosive metal or carbon dusts
c. combustible or explosive plastic dust or flour
d. ignitable textile fibers or sawdust in a wood shop

Answer 48

a. potentially explosive gases, vapors, or liquids

Question 49

An ohm meter pegs out when you hook up the leads. What does this indicate?

a. short
b. open circuit
c. closed circuit
d. capacitor is OK

Answer 49

c. closed circuit

Question 50

If you use an extension ladder to reach a landing on the 2nd floor, how far must the ladder extend above the landing?

a. 12”
b. 24”
c. 32”
d. 36”

Answer 50

d. 36

_{<em>1926.1053(b)(1)</em>}

_{<em>When portable ladders are used for access to an upper landing surface, the ladder side rails shall extend at least 3 feet (.9 m) above the upper landing surface to which the ladder is used to gain access; or, when such an extension is not possible because of the ladder’s length, then the ladder shall be secured at its top to a rigid support that will not deflect, and a grasping device, such as a grabrail, shall be provided to assist employees in mounting and dismounting the ladder. In no case shall the extension be such that ladder deflection under a load would, by itself, cause the ladder to slip off its support.</em>}

Question 51

One 75-watt incandescent bulb is replaced with a 20-watt fluorescent bulb. If the customer is paying $0.45/KWH, how much do they pay per day using the fluorescent bulbs?

a. $0.20
b. $0.22
c. $0.45
d. $0.75

Answer 51

b. $0.22

_{<em>24 hours * 20 watts = 480 watt hours</em>}

_{<em>480 watt hours / 1000 = 0.48 kwh</em>}

_{<em>0.48 kwh * $0.45/kwh = $0.216</em>}

Question 52

When can a basement be counted as a story in calculating living space floor area in a residence?

a. when local codes permit
b. when the ceiling is at least 7-½ feet high
c. when the basement is finished
d. never

Answer 52

c. when the basement is finished

Question 53

You would ground a transformer for a 480Y/277 V service at:

a. the common connection between the 3 phase windings
b. one corner of the “wye”
c. one corner of the “delta”
d. the center tap that provides the neutral

Answer 53

a. the common connection between the 3 phase windings

Question 54

Which arrangement is the wrong order when going from Phase-A to Phase-B to Phase-C in a panel?

a. LEFT to RIGHT
b. BACK to FRONT
c. TOP to BOTTOM
d. BLACK to RED to BLUE

Answer 54

b. BACK to FRONT

Question 55

Which of the following can you use when installing a receptacle near a cleaning station using highly flammable chemicals?

a. PVC 40
b. EMT 10
c. IMC
d. NMC

Answer 55

c. IMC

Question 56

What is the purpose of using a “three-point test” procedure when troubleshooting with a test light or meter?

a. to test watts by connecting current, voltage, and common
b. to gain more clues by measuring three different voltages
c. to detect an intermittent problem
d. safety

Answer 56

d. safety

Question 57

Where can you not use PVC conduit?

a. embedded in concrete
b. in a Class I hazard area
c. buried in soil
d. in wet locations

Answer 57

b. in a Class I hazard area

Question 58

What size conduit should be used for 4/0 service-entrance conductors?

a. 1.25”
b. 1.5”
c. 2”
d. 3”

Answer 58

c. 2”

Question 59

What is the maximum distance outlets should be spaced for kitchen counter tops?

a. 12”
b. 24”
c. 36”
d. 48”

Answer 59

d. 48”

_{<em>The amount of countertop space is used to find the minimum number of receptacles for kitchen (or dining room) wall counter space. Wall counter space is measured horizontally along the wall line at the back of the countertop. Receptacles must be installed so that no point measured horizontally along the wall line is more than 24 inches (600 millimeters) from a receptacle outlet in that space. This requirement is similar to the “6-foot rule” for wall space discussed in Part II of this series. The requirement for counter spaces can be thought of as the “2-foot rule.” Since the maximum distance to a countertop receptacle is 2 feet (600 millimeters), the maximum distance between two receptacles is doubled. Therefore, the maximum distance between two receptacles for counter spaces is 4 feet (1.2 meters).</em>}

Question 60

What is the maximum rating for a garbage disposal on a 20-amp branch circuit?

a. 50%
b. 70%
c. 80%
d. 90%

Answer 60

a. 50%

_{<em>210.23(A) 15- and 20-Ampere Branch Circuits. “A 15- or 20-ampere branch circuit shall be permitted to supply lighting units or other utilization equipment, or a combination of both, and shall comply with 210.23(A)(1) and (A)(2).” Subsection (A)(1) states, “The rating of any one cord-and- plug-connected utilization equipment shall not exceed 80 percent of the branch-circuit ampere rating.” <br></br><br></br>Subsection (A)(2) states, “The total rating of utilization equipment fastened in place, other than luminaires (lighting fixtures), shall not exceed 50 percent of the branch-circuit ampere rating where lighting units, cord-and-plug-connected utilization equipment not fastened in place, or both, are also supplied.”</em>}

Question 61

What is the maximum length of a power cord for a self-contained spa when it is protected by a GFCI?

a. 5’
b. 6’
c. 10’
d. 15’

Answer 61

d. 15’

_{<em>NEC 680.42(a)(2)</em>}

Question 62

According to NFPA standards, when installing a fire-alarm panel and other devices attached to the panel:

a. all components must be purchased at the same time
b. all devices being attached must be UL-approved for the panel
c. all devices must be approved by the authority having jurisdiction, or listed for use with the panel
d. any device that is equivalent to a listed device may be used

Answer 62

c. all devices must be approved by the authority having jurisdiction, or listed for use with the panel

Question 63

What would you need if you wanted a single light fixture to be controlled by two different switches?

a. two-way switches
b. three-way switches
c. single phase switches
d. three-phase switches

Answer 63

b. three-way switches

Question 64

When a fused main is installed in a service panel having breaker branches, all of the following are true except:

a. breakers must interrupt more than 10,000 amps
b. fuses must be current limiting
c. fuses must be listed for use as service equipment
d. panel is listed as “series rated”

Answer 64

a. breakers must interrupt more than 10,000 amps