C-10 Trade 3 Flashcards by Seth Cooper

An example of inductive dielectric heating is a(n):

a. furnace
b. oven
c. microwave
d. heater

c. microwave

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One million watts equal one:

a. kilowatt
b. milliwatt
c. nanowatt
d. megawatt

d. megawatt

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Cal/OSHA requires guardrails for scaffolds over _____ in height.

a. 5’
b. 7-½’
c. 17’
d. 36’

b. 7-½’

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The device used to measure large values of alternating current is a:

a. voltage transformer
b. wattmeter
c. current transformer
d. voltmeter

c. current transformer

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For how much of the normal ampacity must branch circuit conductors supplying continuous loads be sized?

a. 80%
b. 100%
c. 125%
d. 150%

c. 125%

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A 50 kVA transformer supplies 480 V and 40 A. What is its kW rating?

a. 19 kW
b. 40 kW
c. 68 kW
d. 77 kW

a. 19 kW

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The allowable voltage drop of a branch circuit connected to a heater is:

a. 3%
b. 5%
c. 10%
d. 15%

a. 3%

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A 75 kVA, three-phase transformer has 480 V, what is its amperage?

a. 90 amps
b. 60 amps
c. 30 amps
d. 25 amps

a. 90 amps

_{75,000 / 480 = 156.25}

_{156.25 / 1.73 = 90.31 amps}

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The total resistance of three 12-ohm resistors wired in parallel is:

a. 4 ohms
b. 12 ohms
c. 25 ohms
d. 36 ohms

a. 4 ohms

_{A parallel circuit is a circuit in which the resistors are arranged with their heads connected together, and their tails connected together. The current in a parallel circuit breaks up, with some flowing along each parallel branch and re-combining when the branches meet again. The voltage across each resistor in parallel is the same.}

_{The total resistance of a set of resistors in parallel is found by adding up the reciprocals of the resistance values, and then taking the reciprocal of the total:}

_{equivalent resistance of resistors in parallel: 1 / R = 1 / R1 + 1 / R2 + 1 / R3 +…}

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Bending conduit is best done with a:

a. field hickey
b. fixture hickey
c. finial
d. pipe wrench

a. field hickey

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For an electric appliance with a 17.5 A load, the overcurrent device must not exceed:

a. 15 amps
b. 20 amps
c. 25 amps
d. 30 amps

c. 25 amps

_{17.5 * 125%=21.875 (25A next standard size larger)}

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The general lighting load in dwellings is based upon ______ per square foot.

a. 3 watts
b. 5 watts
c. 10 watts
d. 15 watts

a. 3 watts

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Where may you use nonmetallic-sheathed cable?

a. inside floors and walls
b. buried in cinder fill
c. direct burial
d. air conditioning duct

a. inside floors and walls

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The demand factor of a fixed electric space heater is 65%. A central air-conditioning unit in the house has a demand factor of 100%. The air-conditioner also acts as a heat pump. What percent should be added to the heating circuit (i.e., space heater)?

a. 35%
b. 65%
c. 80%
d. 100%

d. 100%

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What type of insulation is needed underground?

a. THW
b. XHHN
c. THN
d. THHN

a. THW

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The current of a high-voltage supply line is best measured with a:

a. voltage transformer
b. clamp-on ammeter
c. current transformer
d. transformer insulated in mineral oil

b. clamp-on ammeter

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In the figure, “X” refers to a(n):

a. fusible line
b. grounding rod
c. grounding electrode
d. equipment ground

c. grounding electrode

If an electrical contractor finds a conflict in the plans who should he/she contact?

a. owner
b. architect
c. engineer
d. prime contractor

d. prime contractor

The smallest size grounding conductor permitted for service entrance is:

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

b. No. 8 copper

After a major accident, Cal/OSHA must investigate within:

a. 3 days
b. 5 days
c. 7 days
d. 10 days

a. 3 days

Portable hand tools at a jobsite require:

a. a DOSH permit
b. a Cal/OSHA permit
c. an EPA permit
d. a GFI

d. a GFI

In a warehouse with a paint spray area with a lot of over spray, where should you install the sub-panel?

a. inside, next to the paint area
b. inside, near the center of the load to be supplied
c. outside, next to the service supply
d. outside, near the center of the load to be supplied

d. outside, near the center of the load to be supplied

The cable that has an internal bonding strip of copper or aluminum in contact with armor for its entire length is:

a. MI
b. AC
c. NMC
d. RMC

b. AC

With what should you treat a burn at a jobsite?

a. loose bandage and antiseptic
b. tight bandage and antiseptic
c. tight bandage only
d. loose bandage only

d. loose bandage only

Where the voltage is limited to 300 volts to ground, service drops over residential property and driveways must have a minimum clearance of: a. 10' b. 12' c. 16' d. 18'

b. 12' _{230.24 Clearances} _{Service-drop conductors must be located so that they are not readily accessible, and they must comply with the following clearance requirements:
(A) Above Roofs. Overhead service conductors must maintain a minimum clearance of 8 ft above the surface of a roof for a minimum distance of 3 ft in all directions from the edge of the roof.} _{Exception No. 2: Where the voltage does not exceed 300V between conductors, overhead conductor clearances from the roof can be reduced from 8 ft to 3 ft, if the slope of the roof exceeds 4 in. in 12 in.} _{Exception No. 3: If the voltage between conductors does not exceed 300V, the conductor clearance over the roof overhang can be reduced from 8 ft to 1.5 ft, if no more than 6 ft of overhead conductors pass over no more than 4 ft of roof overhang, and the conductors terminate at a through-the-roof raceway or approved support. Figure 230-10 230-24Ax3.cdr} _{Exception No. 4: The 3 ft vertical clearance that extends from the roof does not apply when the point of attachment is on the side of the building below the roof.} _{(B) Clearances. Overhead conductor spans for system not over 600V must maintain the following clearances: Figure 230-11 230-24B.cdr} _{(1) 10 ft at the electric service entrance to buildings, at the lowest point of the drip loop of the building electric entrance, above finished grade, sidewalks, or platform or projection from which they might be accessible to pedestrians, where the voltage is not in excess of 150V to ground.
(2) 12 ft above residential property and driveways, and those commercial areas not subject to truck traffic, where the voltage does not exceed 300V to ground.
(3) 15 ft above those areas listed in the 12 ft classification, where the voltage exceeds 300V to ground.
(4) 18 ft over public streets, alleys, roads, parking areas subject to truck traffic, driveways on other than residential property, and other areas traversed by vehicles such as cultivated, grazing, forest, and orchard. Department of Transportation (DOT) type right of ways in rural areas are many times used by slow-moving and tall farming machinery to avoid impeding traffic flow.}

You are replacing a 20-amp receptacle in a bakery and notice a 14 gage wire running from the same circuit to a light. What should you do to correct the problem? a. replace the wire with No. 12 b. install a 15 amp receptacle c. replace the wire with No. 10 d. there is no problem

a. replace the wire with No. 12 _{Replacing with 15A recep is not advised as 20A is required for this application. No. 10 wire is oversized as load is not continuous.}

How long of a tail should you leave for Romex in a box? a. 6" b. 4" c. 8" d. 12"

a. 6" _{NEC (300.14) requires at least 6" of free conductor, measured from the point where the conductor emerges from the cable sheath or raceway, and also the conductors must extend at least 3" from the opening in the box, if any dimension of the opening is less than 8". Note that the 6" is not measured from the front of the box.}

A house is approximately 2300 sq ft and has all-electric major and minor appliances (e.g., washer, dryer, furnace, and A/C). What is the minimum number of branch circuits? a. 4 b. 9 c. 12 d. 14

b. 9

The minimum permitted size fixture wire is: a. No. 14 b. No. 16 c. No. 18 d. No. 20

c. No. 18

In a concrete wall, how far should a junction box be set back? a. no more than ¼" b. no more than ¾" c. no more than 1-¼" d. It must be set flush with surface.

a. no more than ¼"

With a main panel feeding a sub-panel, what is the smallest conductor you can run in parallel? a. 1/0 b. 2/0 c. 3/0 d. 4/0

a. 1/0 _{NEC 310.4} _{(A) General. Aluminum, copper-clad aluminum, or copper
conductors of size 1/0 AWG and larger, comprising each
phase, polarity, neutral, or grounded circuit conductor shall
be permitted to be connected in parallel (electrically joined
at both ends).}

If the plumber accidentally cuts installed wires, to whom should you report the problem? a. electrician b. engineer c. prime contractor d. building inspector

c. prime contractor

What is the maximum distance from a box you should install a pipe strap for EMT? a. 4' b. 3' c. 2' d. 1'

b. 3'

A house is approximately 2300 sq ft and has all-electric major and minor appliances (e.g., washer, dryer, furnace, and A/C). The minimum service required for the house described above is: a. 100 amps b. 125 amps c. 175 amps d. 200 amps

a. 100 amps

What do you not take into consideration when doing load demand calculations? a. range b. general lighting and fixed small appliances c. clothes drier d. small portable heating and cooling appliances

d. small portable heating and cooling appliances

What is the minimum clear working space in front of a 480 V panel opposite exposed live parts? a. 24" b. 36" c. 42" d. 48"

d. 48"

Service entrance equipment panels require bonding jumpers: a. with punched concentric or eccentric knockouts b. on EMT conduits c. on all knockouts d. 1-¼" conduits or larger

a. with punched concentric or eccentric knockouts

A service drop entered and exited a building en route to another building. The electrical contractor that installed the service drop proceeded: a. correctly b. incorrectly: It must remain on the outside of the first building. c. incorrectly: The second building needs its own service. d. incorrectly: Service drops are against code.

c. incorrectly: The second building needs its own service.

What type of voltage do you need in a building (small complex of 100,000 sq ft) that has business machines, computers, programmers, etc.? a. 110/208 V b. 207/440 V c. 277 V d. 408 V

a. 110/208 V

What is the maximum amperage permitted for No. 8 THWN? a. 45 amps b. 50 amps c. 65 amps d. 40 amps

b. 50 amps