C-10 Quiz 1 - Wiring Methods & Conductors

A one-quarter bend in a raceway is equivalent to an angle of _______ degrees.

90 — A quarter bend refers to a 90 degree turn in the pipe or conduit. Therefore, this rule restricts the total angle of bends in one conduit run to be 360 degrees or less.

How many quarter bends are allowed in a 6-foot section of rigid metal conduit between outlet boxes?

4 — Maximum 4 quarter bends (4 x 90 = 360 degrees) between pull points in any conduit run.

How many quarter bends are allowed in an 8-foot section of EMT between outlet boxes?

4 — 4. Reference 2022 CEC 358.26. No more than four quarter bends (360 degrees total) between pull points.

For a residential dwelling, how deep must you bury rigid nonmetallic conduit that is not encased in concrete?

18 inches — 18 inches. Reference 2022 CEC Table 300.5.

PVC conduit must be buried at least _____ under a residential building parking lot.

18 in — 18 in. Refer to CEC Table 300.5. PVC conduit must be buried at least 24 inches under a commercial building parking lot. NOTE: The stronger the material (rigid, semi-rigid) the more shallow (6 inches) the burial. The weaker the protection, the deeper you must bury it.

If a cable is installed under a 3″ concrete pad, what is the minimum earth coverage required?

18″ — Correct answer is C: 18″

What is printed on the label of underground direct-burial wire?

UF — UF (Underground Feeder). Reference 2022 CEC 340.6. Type UF cable and fittings shall be listed for underground direct-burial use.

What type of insulation is needed underground?

USE — USE. 2022 CEC 230.30(B) Wiring Methods.

Direct buried cable in areas subject to heavy vehicular traffic must have a cover of at least:

24 inches — 24 inches. Reference 2022 CEC Table 300.5.

Direct-burial cable carrying 600V must be buried at least:

24 inches — 24 inches unless covered with concrete (then 18 inches). Reference 2022 CEC Table 300.5.

What depth can you place direct burial cables or conductors under one- and two-family dwelling driveways and outdoor parking areas, and used only for dwelling-related purposes?

18 inch — 18 inch (2022 CEC Table 300.5)

Flat conductor cable (Type FCC) is used in branch circuits designed for installation under:

carpet squares — carpet squares. 2022 CEC 324.1. This article covers a field-installed wiring system for branch circuits incorporating Type FCC cable and associated accessories. The wiring system is designed for installation under carpet squares.

A type of cable protected by a spiral metal cover is called _______________ in the field.

BX — BX (also known as Armor Clad or Flexible Metal Conduit cable). BX is sheathed in a flexible metal spiral of aluminum or galvanized steel.

If a wire is #12, what is the maximum length for one set of landscape lights?

56 ft — 56 feet. 3% of 120V = 3.6V allowed drop. Length = (3.6 x 1000) / (2 x 1.6 x 20A) = 56 feet from transformer to last light.

Which of the following is not moisture-resistant?

BXT — All but BXT have "W" ("wet") in their insulation code. BXT is strictly for dry locations. CEC / NEC Article 310

What is meant by AL/CU?

copper-clad aluminum wire — copper-clad aluminum wire

Which of the following is the smallest conductor?

No.10 — In AWG, larger numbers = smaller wire. No. 10 is the smallest of the listed sizes (No.2/0 is the largest).

What is the maximum amperage No. 10 Copper THW may carry?

30 amps — Correct answer is B: 30 amps

What is the minimum size THHN copper wire that may be used in a 200A service?

No. 2/0 AWG copper — No. 2/0 AWG copper is the minimum THHN copper wire size for a 200A service.

What section of the NEC covers wire sizes?

310 — Section 310 Conductors for General Wiring

What is the ampacity of No. 8 THW copper wire?

50 amps — According to CEC, the 8 AWG amp rating of copper THW at 75 °C is 50 Amps. 2022 CEC Table 310.16

Where may you use nonmetallic-sheathed cable?

inside floors and walls — inside floors and walls. 2022 CEC 334.10(A)

Of the following metals, the best conductor of electricity is:

silver — Silver is the best conductor of electricity. Gold and silver can be separated by the cyanide process.

Which of the following colors should not be used for current-carrying wires?

green — Green = ground. CEC / NEC Section 250.119

Type MI cable consists of one or more _______ conductors.

copper — Copper. Type MI cable stands for "Mineral Insulated, Metal-Sheathed" cable, consisting of one or more copper conductors encased within a continuous copper sheath, with magnesium oxide powder acting as insulation.

Where would you use aluminum conductors?

all of the above — All of the above. Aluminum has a superior conductivity-to-weight ratio compared with copper, and is used for wiring in residences, buildings, aircraft and appliances.

As compared with solid wire, stranded wire of the same gauge size is _______________________.

larger in total diameter — Because there are small gaps between the strands, a stranded wire will always have a slightly larger overall diameter than a solid wire with the same AWG.

Stranded wire should be _______________ before being placed under a screw head.

twisted together tightly — When working with stranded wire, it's essential to twist the strands together tightly before securing them under a screw head.

Romex may be used in buildings that do not exceed _____ floors above grade.

3 — Romex (NMC nonmetallic cable) is permitted in buildings not exceeding 3 floors above grade.

Installation of MI cable is prohibited in:

none of the above — None of the above. Reference 2022 CEC 332.12. MI cable is only prohibited where exposed to destructive/corrosive conditions without added protection.

Where would you NOT use nonmetallic sheathed cable?

five story condo — Five story condo. Reference 2022 CEC 334.12(A)(2). NM cable is not permitted exposed in dropped/suspended ceiling cavities in buildings other than one- and two-family or multifamily dwellings.

Conductors of branch circuits supplying more than one receptacle for cord-and-plug-connected portable loads shall have:

an ampacity of not less than the rating of the branch circuit — Reference 2022 CEC 210.19(A)(2).

The minimum permitted size fixture wire is:

No. 18 — #14 is the smallest wire used in circuits. #18 is flexible wire. NEC 400.12 and NEC 402.6

The smallest size wire permitted for general wiring is:

No. 14 — 2022 CEC 620.12. Minimum Size of Conductors.

Where Type NM cable is used as the wiring method for "home runs" for power and lighting branch circuits in a dwelling, the minimum size copper required is _____.

14 AWG — 14 AWG copper is the minimum size permitted for conductors rated 2000 volts or less. (2022 CEC 310.3)

The smallest conductor permitted for general wiring is No. ______ copper or No. ______ aluminum.

14 … 12 — 2022 CEC 310.3(A). Minimum size shall be 14 AWG copper or 12 AWG aluminum or copper-clad aluminum.

When flexibility is not required, AC cable should be stapled or strapped _____ from a box.

1′ — When flexibility is not required, AC cable must be stapled or strapped within 12 inches of a box. (2022 CEC 320.30(B))

The maximum operating temperature for THW insulation is:

75°C — 75°C for dry or wet locations, 90°C only for special applications within electric-discharge lighting equipment. NEC 410.151(A)

Conductors supplying outlets for professional motion-picture projectors must not be smaller than:

No. 8 — 2022 CEC 540.13. Conductors supplying outlets for arc and xenon projectors shall not be smaller than 8 AWG.

Conductors shall NOT be installed in locations where the operating temperature will exceed that specified for the type of ___________ used.

insulation — 2022 CEC 310.14(A)(3). No conductor shall be used such that its operating temperature exceeds that designated for the insulated conductor involved.

Soldered splices must be _______ so as to be electrically secure before soldering.

joined mechanically — The basic requirement of any splice or connection is that it be both mechanically and electrically as sound as the conductor or device with which it is used.

Flexible cords and cables shall not be used ____________.

to run through holes in floors — Flexible cord shall not be used as a substitute for fixed wiring, run through holes in walls/ceilings/floors, run through doorways/windows, attached to building surfaces, or concealed behind building walls/ceilings/floors.

Where installed in raceways, copper conductors ____ and larger shall be stranded.

No.8 — Reference 2022 CEC 310.3(C). Conductors 8 AWG and larger installed in raceways shall be stranded.

No. 4 THW aluminum wire is rated at:

65 amps — According to CEC, the 4 AWG amp rating of aluminum THW at 75 °C is 65 Amps. 2022 CEC Table 310.16

The amperage rating for Copper No. 2 THW is:

115 amps — CEC/NEC Table 310.15(B)(16) (formerly Table 310.16)

The total rating of appliances used on a 20-amp branch circuit should not exceed:

16 amps — (20 amps) x 0.8 = 16 amps.

NM sheathed cable should be secured at intervals no greater than:

4 feet-6 inches — Reference 2022 CEC 334.30. NM cable must be supported at intervals not exceeding 1.4 m (4-1/2 ft).

A stranded wire is given the same size designation as a solid wire if it has the same ______________.

cross-sectional area — The cross section area or circular mill size of a stranded conductor is equivalent to that of a solid conductor for the same designated wire size.

The maximum amperage permitted for copper No. 1 THW is:

130 amps — 2022 CEC Table 310.16

If a No. 8 copper conductor is rated at 50 amps, what would be the corresponding aluminum wire size?

No. 6 — Aluminum conductors generally need to be two gauge sizes larger than copper to carry the same current. NEC Table 310.16

Romex must be protected by guard strips within _____ of an attic access hole without a permanent stairway or ladder.

6′ — 2022 CEC 320.23(A). Protection required within 1.8 m (6 ft) of the nearest edge of the scuttle hole or attic entrance.

Type AC cables require protection within ____ of the nearest edge of an attic entrance without permanent stairs or ladders.

6 feet-0 inches — Reference 2022 CEC 320.23(A).

In which of the following may you use Romex?

a residential garage — Exposed NM/NMC/NMS cable is allowed in one- and two-family dwellings and their attached or detached garages.

The neutral conductor _______________________.

carries the unbalanced current — The neutral conductor is a current-carrying conductor only when it carries the unbalanced current from other ungrounded phase conductors.

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

AC — Type AC. 2022 CEC 320.1 Scope.

Type MC cable can have what type of conductors?

any of the above — Minimum conductor sizes shall be 14 AWG copper, nickel, or nickel-coated copper and 12 AWG aluminum or copper-clad aluminum. Reference 2022 CEC 330.104

The smallest size grounding conductor permitted for service entrance is:

No. 8 copper — 2022 CEC 230.31(B). Conductors shall not be smaller than 8 AWG copper or 6 AWG aluminum or copper-clad aluminum.

Listed ceiling (paddle) fans that do not exceed _____ pounds in weight, with or without accessories, shall be permitted to be supported by outlet boxes identified for such use.

50 — Section 314.27(C). Ceiling-suspended (paddle) fans not exceeding 50 pounds can be supported by listed outlet boxes.

What is the minimum clear working space in front of a 480 V panel opposite exposed live parts?

48″ — The minimum clear working space for 0-150 V is 3 feet. The minimum clear working space for 151-600 V is 4 feet.

What is the minimum clear working space in front of a 480 V panel opposite a grounded wall?

42″ — Refer to Table 110.26(A)(1) which specifies minimum depth of working space for equipment rated 151-600 volts. When opposite a grounded surface (Condition 2), minimum clear distance is 42 inches.

The working space in front of electrical equipment may be used to store:

nothing — Nothing. Reference 2022 CEC 110.26(B). Working space shall not be used for storage.

The minimum depth of the working space in front of a charge controller for which the input-voltage never exceeds 60-volts DC?

Negotiable — Negotiable (by special permission). Per 2019 CEC 110.26(A)(1)(b).

When do the required clearances from overhead high-voltage conductors not apply?

When the overhead electrical distribution and transmission lines have been de-energized and visibly grounded. — Cal/OSHA §2446(b)

Based on Construction Safety Orders, what is the minimum distance a metal ladder should be from exposed energized electrical parts?

10′ — Correct answer is D: 10′

According to Construction Safety Orders, a passenger elevator for hoisting workers must be installed in any building designed to be _____ feet or more in height above or _____ feet in depth below ground level.

60 / 48 — 60 feet high / 48 feet deep. The elevator must be installed and operational when the building reaches 36 feet in height.

The minimum required clearance from overhead high-voltage (600-50,000V) conductors for boom-type lifting and hoisting equipment in transit (where the boom is lowered and there is no load attached) is:

6 feet — Correct answer is B: 6 feet

What is the minimum distance a worker must be from overhead electrical lines energized between 600V and 50,000V?

6 ft — Per California Code of Regulations, Title 8, Section 2946.

What is the minimum number of feet a worker must be from an overhead high-voltage line ENERGIZED BY 600 V TO 50,000 V?

6′ — Title 8, CCR, 2946(a)(B)(2), Table 1. For boom-type equipment, minimum clearance increases to 10 feet under Table 2.

The safe-distance requirement from overhead electrical lines energized between 600 V and 50,000 V is _____ for boom-type lifting when the equipment is in transit with the boom lowered and no load attached.

6′ — Correct answer is B: 6′

What is the maximum height of a ladder-jack scaffold?

16′ — Correct answer is D: 16′

What is the longest span for a scaffold plank used for light duty?

10 ft — Refer to CSO 1637(f)(2)(A). OSHA requires at least a 6-inch lap on each side.

What is the minimum space required between the top of a switchboard and a combustible ceiling?

3 feet — 3 feet minimum clearance required between the top of a switchboard and a combustible ceiling.

What is the minimum working clearance in front of a 240V AC panelboard?

3 feet — Reference 2022 CEC 110.26.

The minimum clearance required from overhead high-voltage (600V-50,000V) conductors for boom-type lifting or hoisting equipment while operating is:

10 feet — Reference ESO 2946.

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

15′ — Correct answer is D: 15′

What is the minimum depth of clear working space for equipment up to 600 volts?

36″ — CEC / NEC Table 110.26(A)(1) under Condition 3.

What is the minimum working clearance in front of an electrical panel under 600V where the live part is on one side and the opposite is insulated or ungrounded?

36" — Reference 2019 CEC Table 110.26(A)(1) Condition 1.

What is the minimum working clearance in front of an electrical panel under 600 V? (Exposed live parts on one side of the working space and no live or grounded parts on the other side of the working space)

36″ — Reference 2022 CEC Table ll0.26(A)(l)

What is a conduit termination called?

dead end — Conduit always terminates at some type of electrical box or at fixed equipment that also serves as a box. CEC / NEC 300.12

The largest size which an EMT can be used is:

4″ — CEC / NEC Section 358.20(B)

Which conduit should you use in an area exposed to corrosive chemicals?

PVC — 2022 CEC 300.6(C). Nonmetallic flexible conduits are ideal for corrosive environments.

Galvanized conduit has a finish exterior and interior of ___________.

zinc — Galvanized piping comprises steel with an additional coating of zinc.

A conduit body is ________________________.

a "LB" or "T", or similar fitting — Each conduit body falls into a category depending on its shape and the location of its removable plate.

Where can you not use rigid PVC?

hazardous locations — 2022 CEC 352.12

Where can you not use PVC conduit?

in a Class I hazard area — Reference 2022 CEC 352.12 Uses Not Permitted.

Exterior connectors used on conduit are:

either water-resistant or waterproof — Depending on UL listing. At minimum they must be raintight; below-grade or immersion requires waterproof.

What is an Erickson coupling used for?

to connect two sections of rigid conduit when one section cannot be turned — The connection is rigid, in-line, and vibration-resistant.

In a concrete wall, how far should a junction box be set back?

no more than ¼” — 2022 CEC 314.20. Flush-Mounted Installations.

What is the maximum distance from a box you should install a pipe strap for EMT?

3′ — 2022 CEC 358.30(A). EMT shall be securely fastened within 900 mm (3 ft) of each outlet box, junction box, device box, cabinet, conduit body, or other tubing termination.

What is the maximum length of flexible metal conduit that can be used without a ground?

6′ — 2022 CEC 348.20(A)(2).

What is the maximum distance between supports in a straight run of EMT?

10 ft — EMT must be supported every 10 ft in straight runs and within 3 ft of a box or other termination.

When re-routing conduit, it may be necessary to increase the wire size, if the distance is greater, in order to __________________________.

compensate for voltage drop — Voltage drop becomes important when the length of a run of wire or cable becomes very long.

Support EMT within ______ of a junction or outlet box.

3 ft — 2022 CEC 358.30(A).

The maximum permitted spacing of clamps (supports) for flexible metal conduit is:

4 feet-6 inches — Reference 2022 CEC 348.30(A). FMC shall be supported at intervals not exceeding 4.5 ft.

What is an enclosure with a flat closed front cover without exposed electrical wiring called?

dead front — A dead front enclosure has no live parts exposed on the operating side of the equipment.

A ___________ is an enclosure designed either for surface or flush mounting and provided with a frame, mat, or trim in which a swinging door or doors are or may be hung.

cabinet — Reference 2022 CEC Article 100.

Enclosed means, surrounded by a _______________ which will prevent persons from accidentally contacting energized parts.

all of the above — California Code of Regulations, Title 8, Section 2700

Electrical equipment must be encased and locked, except when observed by a qualified attendant, if it is more than:

600V — Per OSHA 1926.403(j)(2)(ii).

Equipment of ______ must be located either in a locked room or under supervision of authorized personnel only.

600 volts — Per 2022 CEC 110.34(C).

Rigid metal conduit is available from suppliers in lengths of:

10 ft — Rigid Metal Conduit (RMC) is produced in standard lengths of 10 feet.