Test 4 Flashcards
How can you control the starting speed of direct-current motors?
A. short the field through resistors B. short the field through capacitors C. use a three-phase transformer D. you can't control the starting speed of direct-current motors
A. short the field through resistors
In general, the minimum size of a 200-amp service ground is:
A. No. 16 B. No. 12 C. No. 10 D. No. 4
D. No. 4
A 200-amp service requires a 2/0 service conductor, which requires a minimum size No. 4 grounding conductor.
The rating of a portable appliance used on a 20-amp branch circuit may not exceed:
A. the load of wire B. the general lighting load C. 20 amps plus 20% D. both A and C
A. the load of wire
The three wires of a single-phase 115-230 volt, 200-amp service are designated as A, N, and B. A 100-amp, 230-volt load is connected across wires A and B. A 50-amp, 115-volt load is connected across A and N. The service-to-ground conductor should be:
A. No. 10 B. No. 8 C. No. 6 D. No. 4
D. No. 4
Regardless of the 100- and 50-amp circuits, the 200-amp service must be grounded, which requires 3/0 wire and a No. 4 grounding electrode conductor.
The total rating of appliances used on a 20-amp branch circuit should not exceed:
A. 20 amps B. 16 amps C. 12 amps D. 10 amps
B. 16 amps
Splices and wires within any portion of a gutter shall not fill the cross-sectional area of the gutter by more than:
A. 20% B. 50% C. 60% D. 75%
D. 75%
In order to be classified as “high voltage,” voltage must be greater than:
A. 240 V B. 300 V C. 600 V D. 700 V
C. 600 V
Cord caps on a 220-volt cord for commercial use must be:
A. open front B. dead front C. 50% higher than cord D. none of the above
B. dead front
Title 8, Chapter 4, Subchapter 5 of the California Administrative Code relates to:
A. industrial relations B. health and welfare C. industrial and electrical safety D. both A and B
C. industrial and electrical safety
Subchapter 5 is the Electrical Safety Orders.
Where do you find California’s Building Standards Electrical Code?
A. Title 24 B. Title 14 C. Title 8 D. Building Code
A. Title 24
How can you change the speed of synchronous motors?
A. vary the field strength B. vary the frequency C. short the field through resistors D. you can't change the speed of synchronous motors
B. vary the frequency
How many coulombs are used when one amp is used for one hour?
A. 60 B. 600 C. 3600 D. 6000
How many coulombs are used when one amp is used for one hour?
A. 60 B. 600 C. 3600 D. 6000
What is the resistance of a device that uses 10 amps when connected to 120 volts?
A. 10 ohms B. 12 ohms C. 16 ohms D. 83 ohms
B. 12 ohms
R = E/I = 120 V/10 A = 12 ohms
A resistor is placed across a DC source. What happens to the current if you double the resistance?
A. it is cut in half B. it doubles C. it triples D. it stays the same
A. it is cut in half
If the resistance of a circuit is 10 ohms and the conductor diameter is doubled, the new resistance would be:
A. 2-1/2 ohms B. 5 ohms C. 7 ohms D. 9 ohms
A. 2-1/2 ohms
The greater the cross-sectional area of a conductor, the less the resistance. Doubling the diameter increases the area by a factor of four: Area = πd²/4.
For example, if d = 2:
A = π x (2 x 2)/4 = π x (4/4) = π.
If d is doubled to 4:
A = π x (4 x 4)/4 = π x (16/4) = 4π. So to get the answer, divide 10Ω by 4 to get 2-1/2Ω.
What should you do if there is water in a conduit?
A. nothing, it will evaporate B. drill holes in the conduit C. blow air through the conduit to dry it out D. install drain/seal fittings
D. install drain/seal fittings
Given data as follows: Distance = 2000 feet Current = 30 amps What size wire is required to limit the voltage drop to 10 volts?
A. 6,000 circular mils B. 27,000 circular mils C. 132,000 circular mils D. 620,000 circular mils
C. 132,000 circular mils
Circular mils = (distance (in feet) x amps x 22) ÷ voltage drop = (2000 ft x 30 amps x 22) ÷ 10 volts = 132,000.
What are brushes in motors made of?
A. carbon B. steel C. iron D. nylon
A. carbon
What kind of light is measured in lumens?
A. incandescent light B. fluorescent light C. candle light D. all of the above
D. all of the above
The minimum size of service entrance cable is:
A. No. 2 AWG B. No. 4 AWG C. No. 6 AWG D. No. 8 AWG
D. No. 8 AWG
If the input voltage is 120 volts, the input amperage is 14 amps, and the power factor is .6, then the wattage is:
A. 1680 watts B. 1280 watts C. 1460 watts D. 1008 watts
D. 1008 watts
120 V x 14 A x 0.6 = 1,008 W
In a transformer, if the ratio of input voltage to output voltage is 5 to 1, what is the turn ratio?
A. 1 to 5 B. 5 to 1 C. 10 to 1 D. 15 to 1
B. 5 to 1
How are branch circuit lighting switches rated?
A. amps and volts B. horsepower and volts C. watts D. lumens
A. amps and volts
How are motor control switches rated?
A. amps and volts B. horsepower and volts C. watts D. torque
B. horsepower and volts
When may an electric range be grounded to the neutral conductor?
A. when the neutral is No. 12 copper wire or larger B. when the neutral is No. 12 aluminum wire or larger C. when the neutral is No. 10 copper wire or larger D. when the neutral is No. 10 aluminum wire or larger
C. when the neutral is No. 10 copper wire or larger
This is true only for existing installations. New installations cannot be grounded to the neutral conductor.
Romex may be used in buildings that do not exceed _____ floors above grade.
A. 1 B. 2 C. 3 D. 4
C. 3
In which of the following may you use Romex?
A. a residential garage B. a commercial garage C. concrete D. a theater
A. a residential garage
When drilling through a stud or joist to install Romex, the edge of the hole must be at least ____ from the nearest edge of the stud or joist.
A. 1" B. 1-1/4" C. 1-1/2" D. 2"
B. 1-1/4”
In residences, Romex must be stapled or strapped within _____ of a nonmetallic switchbox.
A. 4" B. 6" C. 8" D. 12"
D. 12”
The smallest conductor that may be used to bond metallic objects around a swimming pool is:
A. No. 4 B. No. 6 C. No. 8 D. No. 10
C. No. 8
A duplex 110 V receptacle with a GFCI must be installed no closer than _____ to the inside wall of a swimming pool.
A. 5' B. 10' C. 15' D. 20'
B. 10’
A duplex 110 V receptacle without a GFCI must be installed no closer than _____ to the inside wall of a swimming pool.
A. 10' B. 15' C. 20' D. 30'
C. 20’
Receptacles in which of the following applications require a GFCI?
A. residential garages B. residential, hotel, and motel bathrooms C. within 20' of a swimming pool D. all of the above
D. all of the above
A service-disconnecting mechanism rated 1000 amps or more requires ground-fault protection of equipment when the voltage to ground is ____ or more.
A. 120 V B. 150 V C. 220 V D. 300 V
B. 150 V
If there are more than ____ conductors in a raceway, you must de-rate the amperage to 80% of full value.
A. 3 B. 6 C. 24 D. 42
A. 3
If there are more than ____ conductors in a raceway, you must de-rate the amperage to 80% of full value.
A. 3 B. 6 C. 24 D. 42
A. 3
If there are more than ____ conductors in a raceway, you must de-rate the amperage to 70% of full value.
A. 3 B. 7 C. 24 D. 42
B. 7
No more than ____ overcurrent devices (other than those in the mains) of a lighting/appliance branch-circuit panelboard must be installed per cabinet or cutout box.
A. 4 B. 7 C. 25 D. 42
D. 42
For a residential dwelling, how deep must you bury rigid nonmetallic conduit that is not encased in concrete?
A. 6" B. 12" C. 18" D. 24"
C. 18”
How deep may you trench in stable soil without shoring?
A. 3' B. 5' C. 6' D. 8'
B. 5’
What type of conductor is used for an open overhead between a garage and a house?
A. THHN B. THWN C. MTW D. UF
B. THWN
What is the minimum length of countertop that requires a convenience outlet?
A. 12" B. 18" C. 24" D. 36"
A. 12”
Ground wire for hospital receptacles must be:
A. bare copper B. insulated copper C. insulated stranded wire D. insulated solid No. 12
B. insulated copper
The load of a branch circuit cannot be over ____ of the overcurrent protection.
A. 60% B. 80% C. 110% D. 125%
B. 80%
Temporary branch circuits or feeders must be supported every:
A. 5' B. 6' C. 10' D. 12'
C. 10’
What is the minimum size ground wire required for a panelboard serving a swimming pool?
A. No. 6 B. No. 8 C. No. 10 D. No. 12
D. No. 12
What is the maximum installation height of a circuit-breaker handle?
A. 5'-0" B. 5'-6" C. 6'-0" D. 6'-6"
D. 6’-6”
How close to combustible material can a recessed incandescent light fixture be installed?
A. 1/2" B. 1" C. 2" D. 3"
A. 1/2”
What is the minimum working clearance in front of a 240 V AC panelboard?
A. 2' B. 3' C. 4' D. 6'
B. 3’
For an electric appliance with a 17 A load, the overcurrent device shall not exceed:
A. 15 A B. 20 A C. 25 A D. 30 A
C. 25 A
How many 110-V/20-A/2-wire circuits are required for a 2500 sq ft house?
A. 4 B. 5 C. 6 D. 7
D. 7
Lighting: 2500 ft x 3 VA/ft = 7500 VA 7500 VA/120 V = 62.5 A, requiring four 20-amp 2-wire circuits. Small appliance circuits: 2 circuits Laundry circuits: 1 circuit TOTAL: 7 circuits.
What is the minimum space required between the top of a switchboard and a combustible ceiling?
A. 1' B. 2' C. 3' D. 4'
C. 3’
How high above grade must a receptacle be in a Class I, Division 2 hazard area?
A. 6" B. 12" C. 18" D. 24"
C. 18”
Several buildings are located on a single property. For how many buildings can a single service-disconnecting switch be used?
A. 1 B. 2 C. 4 D. 6
A. 1
No more than ____ operations of the hand are permitted for a given service.
A. 2 B. 4 C. 6 D. 8
C. 6
A lamp marked “40W, T-12, RS/CW” is:
A. 40 watts, tungsten 12", rapid-start cool-white B. 40 watts, tungsten 12-pin, rapid-start cool-white C. 40 watts, tungsten Type 12, rapid-start cool-white D. 40 watts, bi-pin tubular, 12/8" diameter, rapid-start cool-white fluorescent
D. 40 watts, bi-pin tubular, 12/8” diameter, rapid-start cool-white fluorescent
The minimum size for a service-drop conductor is:
A. No. 6 non-cable B. No. 8 copper C. No. 4 wire D. No. 8 wire
B. No. 8 copper
In a clothes closet, what is the minimum clearance between a surface mounted incandescent light fixture and combustible materials?
A. 12" B. 14" C. 16" D. 18"
A. 12”
Which of the following is a Class III hazardous location?
A. barn B. chemical plant C. textile mill D. gasoline station
C. textile mill
What is the minimum size THHN copper wire that may be used in a 200 A service?
A. No. 2 B. No. 4 C. No. 0 D. No. 000
D. No. 000
Type MC cable must be supported at intervals not exceeding:
A. 6' B. 5' C. 4-1/2' D. 3'
A. 6’
Type MI cable must be supported at intervals not exceeding:
A. 6' B. 4-1/2' C. 3' D. 2'
A. 6’
The maximum size of flexible metallic tubing you may use is:
A. 1/2" B. 3/4" C. 2" D. 4"
B. 3/4”
How many quarter bends are allowed in a 6’ section of rigid metal conduit between outlet boxes?
A. 2 B. 3 C. 4 D. 6
C. 4
How many quarter bends are allowed in an 8’ section of EMT between outlet boxes?
A. 2 B. 3 C. 4 D. 6
C. 4
How many 2-pole circuit breakers are allowed in one panelboard?
A. 12 B. 21 C. 24 D. 42
B. 21
A two-pole circuit breaker is considered to be two overcurrent devices.
In which of the following locations is a ground-fault circuit-interrupter required?
A. kitchens B. bedrooms C. bathrooms D. both A and C
D. both A and C
Installation of MI cable is prohibited in:
A. concrete walls and ceilings B. direct burial C. cinder fill D. none of the above
D. none of the above
You must run conduit through a structurally engineered beam. What should you do?
A. cut a hole B. cut a notch C. consult the architect D. consult the manufacturer
D. consult the manufacturer
The controller of a motor should be located:
A. within sight of the motor B. at the motor control center C. 75' from the motor D. at the motor
A. within sight of the motor
A three-phase air conditioning unit has a motor control of 1200 V, and the disconnect for the motor control is not within sight of the motor. Where should you put the sign directing the service person to the disconnect?
A. on the motor B. next to the motor C. on the controller D. next to or near the controller
C. on the controller
Which of the following devices will draw the least current?
A. vacuum cleaner B. electric stove C. washing machine D. toaster
A. vacuum cleaner
Direct-burial cable carrying 600 V must be buried at least:
A. 6" B. 12" C. 18" D. 24"
D. 24”
Which of the following is the smallest conductor?
A. No. 2/0 B. No. 0 C. No. 2 D. No. 10
D. No. 10
Direct buried cable installed in areas subject to heavy vehicular traffic, such as thoroughfares, must have a cover of at least:
A. 12" B. 18" C. 24" D. 36"
C. 24”
The lead wire on heating cable to be used for a 208 V circuit is identified by the color:
A. black B. red C. blue D. yellow
C. blue
Which subcontractor, along with the electrical subcontractor, should be present for the preliminary inspection of a job?
A. plumbing B. sheet metal C. mechanical D. painting
A. plumbing
What has to be done before the electrician may do any underground work?
A. framing B. dig footings C. plaster D. sheetrock
B. dig footings
Which of the following trades will have to work around all the other trades in underground work?
A. concrete B. plumbing C. electrical D. framing
A. concrete
Which trade will be the first in to do the finish work?
A. plumbing B. mechanical C. sheet metal D. electrical
A. plumbing
Which trade will be the last in to do the finish work?
A. electrical B. plumbing C. painting D. carpeting
D. carpeting
Electrical resistance can be measured with a(n):
A. voltmeter B. wattmeter C. ammeter D. ohmmeter
D. ohmmeter
Voltage can be measured with a(n):
A. voltmeter B. ohmmeter C. ammeter D. wattmeter
A. voltmeter
Current can be measured using a(n):
A. phase-directional meter B. voltmeter C. ohmmeter D. ammeter
D. ammeter
Which instrument would you use for checking continuity of a conductor?
A. voltmeter B. ammeter C. ohmmeter D. wattmeter
C. ohmmeter
A service using a No. 3/0 copper conductor requires the following copper ground:
A. AWG No. 8 B. AWG No. 6 C. AWG No. 4 D. AWG No. 2
C. AWG No. 4
Type AC cable shall be secured at maximum intervals of:
A. 2' B. 4-1/2' C. 6' D. 10'
B. 4-1/2’
Cables associated with data processing equipment shall be permitted under a raised floor provided the branch-circuit supply conductors to receptacles are:
A. Romex B. FCC C. in EMT D. flat ribbon
C. in EMT
Class I hazardous locations are those in which there are ignitable concentrations of:
A. textile fibers B. gas vapors C. grain dust D. none of the above
B. gas vapors
The maximum permitted spacing of clamps (supports) for flexible metal conduit is:
A. 3'-0" B. 3'-6" C. 4'-0" D. 4'-6"
D. 4’-6”
Which of the following will require a skirted plug?
A. 110 V spray gun B. 220 V drill motor C. 440 V welding machine D. none of the above
C. 440 V welding machine
The Safety Code requires jobsite safety meetings:
A. biweekly B. weekly C. daily D. every 10 days
D. every 10 days
Flexible metal conduit may be used for grounding equipment if the total length is not over ____ in any ground return path.
A. 4'-0" B. 4'-6" C. 6'-0" D. 8'-0"
C. 6’-0”
NM sheathed cable should be secured at intervals no greater than:
A. 3'-0" B. 4'-0" C. 4'-6" D. 5'-0"
C. 4’-6”
Type AC cables require protection within ____ of the nearest edge of an attic entrance without permanent stairs or ladders.
A. 2'-6" B. 5'-0" C. 6'-0" D. 7'-0"
C. 6’-0”
Where installed in raceways, copper conductors ____ and larger shall be stranded.
A. No. 10 B. No. 8 C. No. 6 D. No. 4
B. No. 8
Warm air moving into a cold environment can cause:
A. vapors B. corrosion C. condensation D. eddy currents
C. condensation
The minimum clearance required from overhead high-voltage (600 V-50,000 V) conductors for boom-type lifting or hoisting equipment while operating is:
A. 4' B. 6' C. 7-1/2' D. 10'
D. 10’
What should you do if you must bore a hole in a stud that will be less than 1-3/4” from the edge of the wood?
A. add a metal cover over the stud B. call the inspector C. put a rubber bushing over the hole D. you can never have a hole less than 1-1/4" from the edge
A. add a metal cover over the stud
What should you do if you need to drill a hole through an engineered supporting beam?
A. consult an engineer B. consult the general contractor C. drill the hole; no consultation is necessary D. add a metal bushing
A. consult an engineer
The number of smoke detectors shown in the floor plan is:
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 1 B. 2 C. 3 D. 4
B. 2
Hexagons “SD” in back hall and living room near door.
The number of smoke detectors required in the plan and by the Building Code is:
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 1 B. 2 C. 3 D. 4
A. 1
One detector is required in the area immediately outside the sleeping rooms of each separate sleeping area plus in each sleeping area itself.
How many telephone outlets are there?
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 3 B. 7 C. 14 D. 18
C. 14
Find 2 in the dining room, 4 in the living room, 3 in BR1, 2 in BR2, and 3 in the kitchen.
How many fluorescent light fixtures are shown?
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 3 B. 7 C. 8 D. 11
D. 11
Find 3 recessed fluorescent and 7 strip lights under kitchen cabinets, and 1 in stereo cabinet “WS”.
How many recessed light fixtures are shown?
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 4 B. 7 C. 10 D. 13
D. 13
Find 1 in front of the stereo cabinet wall system, 1 in the walk-in closet, 1 light in combination bathroom fixture (special outlet C), 3 in the back hall/pantry area, 3 recessed fluorescents, and 4 incandescents in the kitchen and breakfast bar.
How many light fixtures of all types are shown?
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 13 B. 18 C. 24 D. 30
D. 30
This includes surface, recessed, and fan-mounted incandescent lights, recessed fluorescent, and fluorescent strip-lights.
The number of light switches shown in the plan is:
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 22 B. 24 C. 27 D. 30
D. 30
This includes all one-way, three-way, and four-way switches that are not being used to control a fan or heater.
How many three-way switches are shown in the plan?
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 3 B. 6 C. 7 D. 10
D. 10
Find 4 in the kitchen, 2 in the back hall, 3 in the living room, and 1 in the entry.
How many switched receptacles are shown?
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 0 B. 1 C. 21 D. 22
C. 21
All receptacles in the bedrooms are split-wired with one half of each duplex plug switched. But in the living room and dining room only some receptacles are wired this way.
What is the total number of non-GFCI duplex receptacles, not counting special outlets?
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 34 B. 35 C. 39 D. 46
B. 35
Note that the refrigerator has a single-receptacle outlet represented by one line through the circle. The dishwasher might also have a duplex receptacle, but it is a special outlet and not counted in this question.
How many GFCI-protected receptacles are shown in the floor plan?
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 4 B. 7 C. 12 D. 16
D. 16
Find 11 in the kitchen, 1 in the bathroom, and 4 along the outdoor perimeter. Each protected receptacle is identified in the plan by the initials “GFCI.”
How many small appliance circuits are shown in the floor plan?
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 3 B. 4 C. 5 D. 6
A. 3
A small-appliance circuit provides 20 amps for portable appliances. A garbage disposal would not be included because it is permanently mounted. A washing machine is movable but not portable. Find 2 small appliance circuits in the kitchen. A third circuit is shared between one receptacle in the bathroom and all the outdoor receptacles. The two workshop circuits are not technically “small appliance circuits,” as used here, although they are a similar type of circuit.
What is the kW rating of the oven?
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 4.5 kW B. 5.0 kW C. 5.5 kW D. 6.0 kW
A. 4.5 kW
Consult the load schedule in Sheet 2. Add the VA (volt-amps) in both the A-phase and B-phase columns for the oven: 2250 + 2250 = 4500. In this context VAs are equivalent to watts. Convert to kilowatts: 4500 watts ÷ 1000 = 4.5 kW.
The oven circuit is:
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 2-pole B. 3-pole C. 4-pole D. fused
A. 2-pole
Again, consult the load for the oven. The neutral wire does not count as a “pole” for this question.
What size wire feeds the electric clothes dryer?
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. No. 6 B. No. 8 C. No. 10 D. No. 12
C. No. 10
The information needed to answer this question is not shown in the main floor plan, but is included in the panel list (Sheet 2) in Subpanel-B. A 30-amp circuit requires No. 10 copper wire, which is standard for a dryer. Since this is a new installation, the attachment plug must be the four-prong type with one prong for the ground wire.
What is the total connected amps for Phase B of Panel A?
Please refer to the PDF plans (linked below) to answer the questions 103 - 120. We recommend printing these plans for use during the Practice Test.
C-10 Test 4 - Plan 1 (PDF Download)
A. 73.13 B. 73.85 C. 146.25 D. 192.08
Since this is a single-phase system, what is called a “phase” in the panel schedule is really a pole. “Phase A” is the black wire and “Phase-B” is the red wire in the main panel feed. The total number of connected amps assumes that every circuit is used at its rated load, which would never happen, so it is much greater than the calculated load. In Sheet 2, the connected volt-amps (VA) are listed for each phase at the lower left corner of each panel schedule. For the connected amps of the whole panel, the VA of the two phases are added, then divided by the 240 V between phases. But the individual phases are 120 V, so you divide the Phase-B VA by 120 V instead. The phases are not perfectly balanced, so you cannot divide the total VA by 2 to get the Phase-B amps. The connected VA listed under panel B does not need to be added to Panel A to answer this question because Panel B is already included via the 50-amp, two-pole breaker that feeds it.