Unit 12: General Practice

Question 1

Fill in the blank:

According to the NEC®, a correct provision for an equipment bonding jumper is that ________.

Answer 1

an equipment bonding jumper is permitted to be a wire, bus, or screw.

Question 2

Fill in the blank:

Where a 15- or 20-ampere rated branch circuit supplies three (3) 15-ampere rated receptacles, the MAXIMUM load any one receptacle is permitted to carry is ________.

Answer 2

12 amperes

Question 3

Fill in the blank:

Where a surface-mounted luminaire containing a ballast or transformer is to be located on combustible low-density cellulose fiberboard, the ballast or transformer shall be marked for this condition or shall be spaced NOT less than ________ from the surface of the fiberboard.

Answer 3

1 1⁄2 in.

Question 4

Fill in the blank:

A metal device box to be installed will contain one (1) duplex receptacle, two (2) internal cable clamps and two (2) size 12/2 with ground nonmetallic sheathed cables. To comply with NEC® standards the device box must have a volume, in cubic inches, of at LEAST ________.

Answer 4

18.00 cubic inches

2 ungrounded conductors = 2 x 2.25 cu. in. = 4.50 cubic inches
2 grounded conductors = 2 x 2.25 cu. in. = 4.50 cubic inches
2 grounding conductors = 1 x 2.25 cu. in. = 2.25 cubic inches
2 cable clamps = 1 x 2.25 cu. in. = 2.25 cubic inches
1 device = 2 x 2.25 cu. in. = 4.50 cubic inches
Total = 18.00 cubic inches

Question 5

Fill in the blank:

On a 4-wire delta-connected system, the conductor having the higher phase voltage to ground shall be durably and permanently marked by an outer finish that is ________ in color or by other effective means if the grounded conductor is also present.

Answer 5

orange

Question 6

Fill in the blank:

Resistance-type heating elements in fixed electric space heating equipment shall be subdivided into loads NOT exceeding ________.

Answer 6

48 amperes

Question 7

Fill in the blank:

When a receptacle outlet is removed from an underfloor raceway, the conductors supplying the outlet ________.

Answer 7

shall be removed from the raceway

Question 8

Fill in the blank:

For other than listed low-voltage luminaires not requiring grounding, wet-niche luminaires installed in permanently installed swimming pools shall be connected to an insulated copper equipment grounding conductor NOT smaller than ________.

Answer 8

12 AWG

Question 9

Fill in the blank:

Disregarding exceptions, the MINIMUM size grounded or ungrounded conductors permitted to be connected in parallel (electrically joined at both ends) is ________.

Answer 9

1/0 AWG

Question 10

Fill in the blank:

For track lighting located in other than dwelling units, or guest rooms or suites of hotels or motels, a load of ________ shall be calculated for every two (2) feet of lighting track or fraction thereof.

Answer 10

150 VA

Question 11

Fill in the blank:

Branch circuits supplying one or more information technology units or data processing units shall have an ampacity (current-carrying capacity) of NOT less than _______\__ of the total connected load.

Answer 11

125%

Question 12

Fill in the blank:

Where installed in an ambient temperature of not more than 86°F, Type SRD multiconductor flexible cable consisting of size 8 AWG conductors and only two (2) conductors in the cable are current-carrying, the ampacity of the conductors is ________.

Answer 12

40 amperes

Question 13

A fifty (50) ft. run of Schedule 40 PVC conduit is to contain the following copper conductors:

• four (4) size 1 AWG XHHW
• one (1) size 6 AWG bare

Determine the MINIMUM trade size Schedule 40 PVC required as per the NEC®.

Answer 13

1 1⁄2 in.

Size 1 AWG XHHW = .1534 sq. in. x 4 wires = .6136 sq. in.
Size 6 AWG bare = .0270 sq. in.
Total = .6406 sq. in.
A trade size 11⁄2 in. Schedule 40 PVC with an allowable fill of .794 sq. in. should be selected from Table 4 of Chapter 9.

Question 14

Fill in the blank:

For circuits over ________ to ground, the electrical continuity of rigid metal conduit (RMC) that contain any conductor, other than service conductors, shall be insured with two (2) locknuts, one inside and one outside of boxes and cabinets.

Answer 14

250 volts

Question 15

Fill in the blank:

In regard to dwelling units, at LEAST ________ branch circuit(s) shall be provided to supply the laundry equipment receptacle outlet(s).

Answer 15

One 20-amperes

Question 16

Fill in the blank:

Given: An 18 cubic inch Type FS device box that contains a receptacle is supported only by two (2) underground installed rigid metal conduits that are made-up wrench-tight into the box. Each conduit shall be secured within at LEAST ________ of the box.

Answer 16

18 inches

Question 17

Where a conductor is marked RHW-2 on the insulation, what does the -2 represent?

Answer 17

The conductor has a maximum operating temperature of 90°C.

Question 18

Fill in the blank:

Drywall or plasterboard surfaces that are damaged around boxes having a flush-type cover or faceplate shall be repaired so there will be no gaps greater than ________ at the edge of the box.

Answer 18

1/8 in.

Question 19

Fill in the blank:

All electrical equipment including boxes, cabinets and raceways installed in Class I, Division 1 or 2 locations shall be ________ equipment.

Answer 19

explosionproof

Question 20

Where the service-entrance conductors for a commercial occupancy are size 350 kcmil aluminum, what size copper grounding electrode conductor would be required? (Assume the grounding electrode conductor extends to multiple electrodes.)

Answer 20

2 AWG

Question 21

Fill in the blank:

Single-conductor cable in exposed outdoor locations in solar photovoltaic (PV) systems dc circuits within the PV array, shall be permitted to be Type ________.

Answer 21

USE-2

Question 22

What is the approximate horsepower rating of a 240-volt, single-phase motor that draws 18.5 amperes of current, with an efficiency of 85 percent?

Answer 22

5 hp

HP = I x E x Eff./ 746 watts
NOTE – 1 hp = 746 watts

HP = (18.5 amps x 240 volts x .85 eff.)/746 watts
= 3,774/ 746
= 5.05 hp

Question 23

Fill in the blank:

Where exposed Type NM cable passes through a floor, the cable shall be protected from physical damage by an approved means extending at LEAST ________ above the floor.

Answer 23

6 inches

Question 24

Fill in the blank:

Branch circuit outlets supplying 120-volt or 240-volt, single phase, swimming pool pump motors of 60-amperes or less, for a permanently installed swimming pool shall be provided with Class A GFCI protection for personnel when ________.

I. cord-and-plug connected to a receptacle
II. direct connected (hard-wired)

Answer 24

Either I or II

Question 25

# True or False: Recessed luminaires installed in suspended ceilings shall be attached to the ceiling framing members by clips, screws or rivets listed and identified for use with the luminaire and ceiling framing members.

Answer 25

TRUE