Deck 6: Determining Branch Circuit, Feeder Circuit, and Service Entrance Requirements

Question 1

A(n) __________ is the circuit conductors between the final overcurrent device and the outlets.

A) open circuit
B) branch circuit
C) feeder circuit
D) service conductor

Answer 1

B

Question 2

The rating of a panelboard is based on the ampacity of the __________.

A) main breaker
B) buss bar
C) service conductor
D) total amperage of each breaker in the panelboard

Answer 2

B

Question 3

When doing a standard service entrance calculation, if a residence has four fixed appliances, a demand factor of __________% is applied to the total load of these appliances.

A) 50
B) 75
C) 80
D) 100

Answer 3

B

Question 4

Section 230.79(C) requires that for a single-family dwelling, the service disconnecting means must have a rating of not less than 100 amps.

Question 5

Which of the following areas is included when computing the general lighting load of a house?

A) Open Porches
B) Garages
C) Crawl spaces
D) Finished basements

Question 6

The NEC ^® defines a branch circuit as the circuit conductors between the service equipment and the power or lighting outlets.

Question 7

Which of the following is not permitted to be connected to a small appliance branch circuit?

A) Refrigerator
B) Electric clock
C) Gas stove
D) Kitchen lighting fixture

Question 8

A 200-ampere rated panel is designed and manufactured to accommodate __________ circuits.

A) 30
B) 40
C) 42
D) Could be any of the above

Question 9

A supplemental grounding electrode is a grounding electrode used to 'back-up' a metal water pipe grounding electrode.

Question 10

When doing branch circuit, feeder, and service entrance calculations, one volt-amp equals __________.

A) one joule
B) one watt
C) one ohm
D) one mil

Question 11

The circuit conductors between the service equipment and the final branch circuit overcurrent protection device is a(n) __________.

A) open circuit
B) branch circuit
C) feeder circuit
D) service conductor

Question 12

If cables are bundled together for more than 24" and the total number of current-carrying conductors exceeds __________, the ampacity of the conductors must be derated.

A) 2
B) 3
C) 4
D) 5

Question 13

In a residential wiring, which of the following house areas does not have its power supplied by a small appliance circuit?

A) Bathroom
B) Dining room
C) Kitchen
D) Pantry

Question 14

Kitchen lighting outlets are permitted to be connected to any of the small appliance branch circuits that provide power for the kitchen receptacles.

Question 15

Which of the following loads does not require a grounded circuit conductor?

A) 2-wire, 120 volt
B) 3-wire, 120/240 volt
C) 2-wire, 240 volt
D) None of the above

Question 16

An area including a basin with one or more of the following: a toilet, a urinal, a tub, a shower, a bidet, or similar plumbing fixtures is called a bathroom according to the NEC.

Question 17

When doing a standard service entrance calculation and applying the demand factor to the total load of the general lighting load, the small appliance circuits, and the laundry circuit, the first ___________ volt-amps are computed at 100%

A) 2,000
B) 2,500
C) 3,000
D) 4,000

Question 18

A house with 2,000 square feet of habitable living space will require at least _________ general lighting circuits if 15-ampere circuit breakers are used to provide circuit protection.

A) 3
B) 4
C) 5
D) 6

Question 19

The point on the wiring system at which current is taken to supply electrical equipment is called a receptacle.

Question 20

According to the NEC, the unit load used to calculate the minimum number of general lighting circuits in a dwelling is __________ volt-amperes per square foot.

A) 2
B) 3
C) 4
D) 5

Question 21

For the types of branch circuits found in residential wiring, the fuse or circuit breaker size can never be larger than ____________________ amps for a 12 AWG copper conductor.

Question 22

The NEC states that the load for a household electric dryer must be computed at ____________________ watts or the nameplate rating, whichever is greater.

Question 23

If the total computed load of a residence is 45,840 volt-amperes, the computed amperage of the residence is ____________________ amps.

Question 24

According to Table 310.15(B)(16) in the NEC, the ampacity for a 3 AWG copper conductor using the 75 degree Celsius column is ____________.

A) 85 amps
B) 95 amps
C) 100 amps
D) 200 amps

Question 25

The NEC requires at least ____________________ small appliance circuits be installed in each dwelling unit.

Question 26

Dividing the total computed load in volt-amperes by the residential service voltage of ____________________ volts will give the minimum ampacity the service conductors must be rated for.

Question 27

When cables or conductors are physically tied, wrapped, or taped together, they are considered to be ______________.

A) bundled
B) messy
C) supported
D) secured

Question 28

A 1900 square foot residence has a general lighting load of ____________________ volt-amperes.

Question 29

The minimum service entrance rating for a single-family home permitted by the NEC is __________ amperes.

A) 60
B) 75
C) 100
D) 200

Question 30

A household electric range has a rating of 11 kW. When computing the service load using the standard calculation, a minimum of ____________________ watts will be used.

Question 31

If an electric dryer has a nameplate rating of 4,500 watts, ____________________ watts will be used in the standard method service calculation.

Question 32

According to NEC Section 310.15(B)(7) in the NEC, the minimum conductor size for a 300 ampere residential service entrance is _________ CU or _________ AL.

A) 2 AWG; 1/0 AWG
B) 2/0 AWG; 4/0 AWG
C) 250 kcmil ; 350 kcmil
D) 400 kcmil ; 600 kcmil

Question 33

According to Table 310.15(B)(16) in the NEC, the ampacity for a 12 AWG copper conductor using the 60 degree Celsius column is ____________.

A) 20 amps
B) 25 amps
C) 30 amps
D) 40 amps

Question 34

The NEC states that each two-wire small appliance circuit shall be computed at ____________________ volt-amperes.

Question 35

According to Section 310.15(B)(7)(1), for one-family dwelling service entrance ratings of 100 through 400 amps the service conductors can have a rating of _____ percent of the service rating.

A) 73
B) 83
C) 100
D) 125

Question 36

Another way to calculate the minimum number of general lighting circuits required in a dwelling unit is to divide the total habitable square foot living area by ____________ square feet for 15 amp branch circuits and ______________ square feet for 20 amp branch circuits.

A) 200/300
B) 600/800
C) 750/1000
D) 1500/2000

Question 37

The temperature of the air that surrounds an object on all sides is called ________ temperature.

Question 38

All of the following types of branch circuits are found in residential wiring except:

A) general lighting
B) laundry
C) large appliance
D) small appliance

Question 39

The current in amperes that a conductor can carry continuously under certain conditions of use without exceeding its temperature rating is called __________.

Question 40

According to NEC Section 310.15(B)(7) in the NEC, the minimum conductor size for a 200 ampere residential service entrance is _________ CU or _________ AL.

A) 4 AWG; 2 AWG
B) 3 AWG; 1 AWG
C) 2 AWG; 1/0 AWG
D) 2/0 AWG; 4/0 AWG

Question 41

A house will have an electric range that has a nameplate rating of 14 kW. What is the load used to calculate the branch circuit rating?

Question 42

A house will have a counter-mounted cooking unit with a nameplate rating of 4 kW and a wall-mounted oven with a nameplate rating of 6 kW. A separate individual branch circuit will be run to the counter-mounted cooking unit and to the wall-mounted oven. What is the branch circuit load for each of the appliances in amperes?

Question 43

When is bathroom lighting permitted to be connected to the 20-amp rated bathroom branch circuit?

Question 44

How are the electric heating and the air conditioning loads computed when calculating the total electrical load for a residential service?

Question 45

When are sub-panels used in residential wiring?

Question 46

A house will have an electric range that has a nameplate rating of 11.5 kW. What is the branch circuit load for the range?

Question 47

A house will have a countertop cook unit rated at 5 kW and a built-in oven rated at 7 kW. Both will be connected to the same branch circuit. What is the load used to calculate the branch circuit rating?

Question 48

List at least 5 types of branch circuits found in residential wiring.