C-10 Trade 2 Flashcards by Seth Cooper

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

c. check with the utility company

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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

c. it keeps the interior volume of the pipe unchanged

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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

a. a short

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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

c. the authority having jurisdiction

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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

d. an explosion will not occur inside rated equipment

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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

b. $0.42

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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

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

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Exterior connectors used on conduit are:

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

c. either water-resistant or waterproof

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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

b. fluorescent

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The allowed wire fill in a nipple is usually:

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

b. 60%

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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

b. black

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Where would you not use nonmetallic sheathed cable?

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

d. five story condo

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What is the maximum height for an office light switch?

a. 24”
b. 36”
c. 48”
d. 60”

c. 48”

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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

a. use floor receptacles

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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

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

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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

d. electric power lines

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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

d. all of the above

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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

d. wye - wye

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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

b. 4, 5, & 6

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

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

a. 50%

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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

b. light industrial building

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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

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

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

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

d. prime contractor

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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’

b. 10’

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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

b. reversed hot and traveler conductors

Which of the following substances is now regulated by Title 8? a. concrete b. asbestos c. plaster board d. electric wire

b. asbestos

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

b. No. 10

The wire fill permitted at all points in an auxiliary gutter is: a. 20% b. 30% c. 40% d. 75%

a. 20% _{366.22 Number of Conductors.
(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
or controller conductors between a motor and its starter and used only for starting duty shall not be considered as current-carrying conductors.
(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.
366.23 Ampacity of Conductors.}

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

b. open circuit neutral

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

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

Which should you not use for motor overload protection? a. single element fuse b. dual element fuse c. thermal relay d. magnetic relay

a. single element fuse

Sheet metal raceways must be secured every ___ along the entire length. a. 3' b. 4' c. 5' d. 6'

c. 5' _{376.30 Securing and Supporting. Metal wireways shall be supported in accordance with 376.30(A) and (B).
(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).
(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.}

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

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

Electrical conduits on gasoline islands must be sealed to a minimum height of: a. 18" b. 24" c. 36" d. 48"

d. 48"

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

c. compact, fast acting, and high interrupt rating

In fire alarm systems, the wire coming out of the alarms must be: a. mechanically supervised b. electronically supervised c. manually supervised d. unsupervised

b. electronically supervised

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%

c. 40%

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

d. the power company

Why would you use a dry transformer? a. to increase potential b. to decrease potential c. to increase current d. to decrease current

b. to decrease potential

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

b. 200 amps

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

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

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

d. Both A & B

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

c. seal-off fittings

What section of the NEC covers wire sizes? a. 100 b. 310 c. 500 d. 680

b. 310

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

d. core drill

The allowed wire fill in a nipple is usually: a. 20% b. 60% c. 75% d. 00%

b. 60% _{Note (4) in Chapter 9 of NEC 2011:

"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."}

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

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

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

a. potentially explosive gases, vapors, or liquids

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

c. closed circuit

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"

d. 36 _{1926.1053(b)(1)} _{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.}

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

b. $0.22 _{24 hours * 20 watts = 480 watt hours} _{480 watt hours / 1000 = 0.48 kwh} _{0.48 kwh * $0.45/kwh = $0.216}

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

c. when the basement is finished

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

a. the common connection between the 3 phase windings

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

b. BACK to FRONT

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

c. IMC

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

d. safety

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

b. in a Class I hazard area

What size conduit should be used for 4/0 service-entrance conductors? a. 1.25" b. 1.5" c. 2" d. 3"

c. 2"

What is the maximum distance outlets should be spaced for kitchen counter tops? a. 12" b. 24" c. 36" d. 48"

d. 48" _{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).}

What is the maximum rating for a garbage disposal on a 20-amp branch circuit? a. 50% b. 70% c. 80% d. 90%

a. 50% _{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."

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."}

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'

d. 15' _{NEC 680.42(a)(2)}

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

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

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

b. three-way switches

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"

a. breakers must interrupt more than 10,000 amps