Deck 18: Wiring Methods

Question 1

On a three-phase 208/120 V system, the color typically used to identify the neutral is ____.

A) black
C) white
B) red
D) green with yellow stripe

Answer 1

C

Question 2

What is the minimum trade size RMC permitted for four 4/0 AWG and one 2/0 AWG THW copper conductors supplying a panelboard feeding combination loads?

A) 1-1/4 in.
C) 2 in.
B) 1-1/2 in.
D) 2-1/2 in.

Answer 2

D

Question 3

What is the minimum trade size EMT permitted for twelve 12 AWG THWN copper conductors supplying a junction box that feeds fluorescent luminaires?

A) 1-1/4 in.
C) 3/4 in.
B) 1 in.
D) 1/2 in.

Answer 3

C

Question 4

On a single-phase 120/240 V system, the color typically used to identify the grounding conductor is ____.

A) green
C) yellow
B) white
D) brown

Question 5

What is the minimum trade size RNC Schedule 40 permitted for four 2/0 AWG, six 6 AWG, and twenty 12 AWG THWN copper conductors?

A) 2 in.
C) 3 in.
B) 2-1/2 in.
D) 3-1/2 in.

Question 6

"Allowable ampacity" is defined as ____.

A) the current in amperes that a conductor can carry continuously under the conditions of use without exceeding the temperature rating
B) the amount of current a conductor can carry without causing the overcurrent protective device to trip or blow
C) the amount of current that is limited by the rating of the overcurrent protective device
D) the amount of current that a resistor will allow to flow in a conductor

Question 7

What is the minimum trade size LFMC permitted for two 3 AWG and one 6 AWG THW copper conductors feeding a small motor control center?

A) 1-1/4 in.
C) 2 in.
B) 1-1/2 in.
D) 2-1/2 in.

Question 8

White, or natural gray-colored insulation is ____.

A) unrestricted in usage
B) restricted from usage on any grounding conductor
C) restricted from usage on any grounded conductor
D) restricted from usage on any ungrounded conductor

Question 9

On a three-phase system with voltages greater than 600 V, the typical color used to designate phase Z(C) is ____.

A) red
C) blue
B) black
D) white

Question 10

On a three-phase 480/277 V system, the color typically used to identify phase X(A) is ____.

A) brown
C) yellow
B) orange
D) green

Question 11

What is the minimum trade size RMC permitted for four 6 AWG, four 1 AWG, six 2 AWG, and two 3 AWG RHW-2 copper conductors?

A) 2 in.
C) 3 in.
B) 2-1/2 in.
D) 3-1/2 in.

Question 12

A single-phase electrical device in a building draws 37 A and is supplied with two type THWN copper wires in a conduit. The conduit is run up through the cores of concrete blocks in a building. The wire ampacity is to be sized at 125% of the 37 A, which is 46.25 A. The minimum size of wire permitted is AWG number ____.

A) 4
C) 8
B) 6
D) 10

Question 13

The NEC® requires the high leg of a four-wire delta transformer to be identified by a(n) ____.

A) red overall finish
C) blue overall finish
B) orange overall finish
D) yellow overall finish

Question 14

Single aluminum conductors with type XHHW insulation are mounted overhead on insulators to supply an outbuilding from another building. The 120/240 V, three-wire feeder is protected at the source with a 100 A circuit breaker. The minimum size ungrounded feeder conductors permitted are ____ AWG.

A) 4
C) 8
B) 6
D) 10

Question 15

Wire type THWN copper is run in a raceway from a wall outlet in a building under concrete floor where the conduit is in contact with the earth. The walls are exposed on both sides to free air. If the load requires a minimum wire rating of 75 A, the minimum wire size permitted is ____ AWG.

A) 4
C) 8
B) 6
D) 10