Deck 4: Panelboards

Question 1

If there is any question as to the exact value of the short-circuit current available at a point, a circuit breaker with interrupt rating is to be installed.

A) no
B) low
C) medium
D) high

Answer 1

D

Question 2

The voltage ratings of the breakers must be higher than that of the system. Breakers are usually rated at 250 or volts.

A) 300
B) 400
C) 500
D) 600

Answer 2

D

Question 3

In general, in a circuit breaker, a low setting may be times the overload rating.

A) two to four
B) six to eight
C) ten to twelve
D) fourteen to sixteen

Answer 3

C

Question 4

Two single-pole breakers require installation space that of a double-pole breaker.

A) a quarter
B) one-half
C) equal to
D) double

Question 5

What should the selection of a circuit breaker be based on?

Question 6

Panelboards that are not lighting panelboards are known as or distribution panelboards.

A) circuit-breaker
B) power
C) fused
D) feeder

Question 7

What requirements should be followed for lighting and appliance panelboards?

Question 8

The main for a panelboard may be either a(n) or a circuit breaker.

A) fuse
B) appliance
C) busbar
D) pole

Question 9

Briefly discuss panelboard installations that do not require a main protective device and then outline situations in which individual protection is required.

Question 10

If subfeed lugs are used, the electrician must ensure that the lugs are suitable for making .

A) taps
B) multiple connections
C) one connection
D) lighting boards

Question 11

When a subfeeder serves more than one panelboard, then connections must be made in the subfeeder for .

A) each panelboard
B) every other panelboard
C) each set of three panelboards
D) each set of four panelboards

Question 12

The temperature rating of conductors must be selected and coordinated after consideration of the of any connected termination, conductor, or device.

A) lowest temperature rating
B) highest temperature rating
C) current load
D) voltage load

Question 13

For a three-pole circuit breaker, pole(s) is (are) required for each breaker used.

A) one
B) two
C) three
D) four

Question 14

Adjustments of the determine the degree of protection provided by the circuit breaker if a short circuit occurs.

A) magnetic trip
B) double pole
C) triple pole
D) overcurrent

Question 15

The trip rating of the circuit breaker cannot exceed the ampacity of the in the panelboard.

A) fuses
B) appliances
C) switches
D) busbars

Question 16

Panelboards are available with standard main ratings of 100, 225, 400, 600, 800, and amperes.

A) 900
B) 1000
C) 1100
D) 1200

Question 17

What rules should be followed to set the magnetic trip?

Question 18

As a general rule, a panelboard for which more than 10 percent of its overcurrent devices are rated at amperes or less, and for which neutral connections are provided, is defined as a lighting and appliance branch-circuit panelboard.

A) 10
B) 20
C) 30
D) 40

Question 19

Circuit control and protection must be provided for all circuits and the power-consuming devices connected to these circuits.

A) lighting
B) appliance
C) busway
D) overcurrent

Question 20

When planning or diagramming a floor-mounted transformer supplying a power panelboard, what are important components to include?