C10 T Exam Questions and Answers Latest
Update
Terms in this set (132)
Question #: 1: When troubleshooting Correct answer: bad capacitor
a motor capacitor, the meter pegs to Additional Notes: If the capacitor were good, the needle would peg to
the right and stays there. What does the right, then slowly drop back down.
this indicate?
Question #: 2: On a 480 V, three- Correct answer: overloaded motor
phase blower motor with auxiliary
contacts and indicators, the push
button start is off due to a thermal
overload. What is the most likely
cause?
7'-6"
When installing a fire alarm system Additional Notes: The top of the device should be at least 7'-6" above
bell or horn, how far above grade the finished floor and at least 6" below the finished ceiling. If the ceiling
should it be mounted? height is too low to allow the recommended mounting heights, the
device can be mounted at a lower height, or on the ceiling.
What is the minimum length of a 8'
grounding rod?
When testing a GFCI trip, probe inductive voltage tester
conductor and fixture ground, use:
On a walk-through of a new home, would need to install 2 outlets
the owner wants you to install an
outlet beside the stove. The counter
top is 48" long and the wall is 6'
away. The contractor
Correct answer: 1/8"
What is the maximum allowed gap
Additional Notes: Plaster, drywall, or plasterboard surfaces must not
allowed around a box in a wall
have gaps or open spaces greater than 1/8" at the edge of a box or
finished with drywall?
fitting.
What is the minimum number of Correct answer: two; one from the emergency electrical system and the
branch circuits required at each other from the normal system
patient bed location?
, Correct answer: when you are reducing vibration and noise on the
When can you have an isolated ground
ground passing through a panel Additional Notes: When installing an isolated ground receptacle the
without connecting it to that panel's insulated equipment grounding conductor is run with the circuit
equipment grounding terminal bar? conductors directly back to the main service disconnect. Metal boxes
and raceways must still be grounded.
Correct answer: the service pit is inadequately ventilated
Which of the following could cause Additional Notes: The entire area of repair garages, up to a level of 18"
a significant increase to the bid above the floor, are Class I, Division 2, locations. Any depression below
amount on a job at an automotive floor level (such as a service pit) is also a Class I, Division 2, location
repair shop? unless it is unvented in which case it may be considered a Class I,
Division 1, location and require special fittings.
What would you use in a capacitive inductor
reactance circuit to balance the
circuit?
Which of the following NEMA rating Correct answer: NEMA 3R
should be used for temporary Additional Notes: Enclosures with a NEMA rating of 3R is designed for
construction power enclosures indoor or outdoor use. Enclosures with ratings of 1, 2, or 12 are designed
outside? for indoor use only.
Correct answer: 103 amps
Additional Notes: To find the amperage of a three-phase motor when
What is the full-load current rating of
you know the horsepower you use a variation of Watt's Law:
a 208-volt, 50-horsepower, three-
I = (horsepower x 746 watts/horsepower) / (E x 1.73)
phase squirrel-cage motor?
I = (50 hp x 746 watts/hp) / (208 volts x 1.73) = 37,300 watts / 360 volts =
103 amps
When connecting conduit in a Correct answer: seal-off fitting
hazardous area, what do you use in
order to prevent the passage of
gasses, vapors, or flames?
When a house heater comes on, Correct answer: bad neutral connection
some lights get bright, others get
dim. What could cause this?
What is the difference between a Correct answer: a grounded conductor is a circuit conductor that is
grounded conductor and a intentionally grounded and a grounding conductor is a conductor that is
grounding conductor? used to connect the grounded circuit to a grounding electrode
Correct answer: press the test button
Additional Notes: All GFCI outlets come with a "test" button that induces
How do you test a GFCI? a small ground. To test, plug in a light, turn it on and press the "test"
button. The button should pop out and the light should go out.
(Sometimes only ONE of these things will happen!)
If the phase-to-neutral voltage in a Correct answer: 4,150 volts
three-phase, Y-connected system is Additional Notes: To find the phase-to-phase voltage in a three-phase
2400 volts, what is the phase-to- system, multiply the phase-to-neutral voltage by the square root of three
phase voltage? (the "three-phase factor"): 2,400 volts x 1.73 = 4,152 volts.
, On a 480 V, three-phase blower Correct answer: internal short
motor with auxiliary contacts and
indicators, a fuse is blown. What is
the most likely cause?
Correct answer: 14
Additional Notes: The number of circuits = total load (VA) / capacity of
each circuit (VA)
A store building measuring 60 ft x 80
The general lighting load for stores is 3 VA per sq ft: (60ft x 80ft) x 3
ft is supplied by a 120/240-volt,
VA/sq ft = 14,400 V A.
three-phase, four-wire system, and
The lighting load for show window is 200 VA per linear ft: 60 ft x 200
has 60 linear feet of show windows.
VA/ft = 12,000 VA
What is the minimum number of two-
Total lighting load = 14,400 VA + 12,000 VA = 26,400 VA x 1.25 (125% for
wire, 20- ampere branch circuits
continuous loads) = 33,000 VA.
required to supply the continuous
Although supplied by a three-phase system, the two-wire, 120-volt
general lighting and show window
branch circuits are single-phase (so you don't need to use the three-
lighting for the building?
phase factor in your calculations).
The capacity of each circuit = 120 V x 20A = 2400 VA
33,000 VA / 2400 VA = 13.75, which rounds up to 14 circuits.
In addition to the type of Correct answer: occupancy
construction, how does the NEC
classify buildings?
Correct answer: 1/16"
Additional Notes: When cable- or raceway-type wiring is installed
through wood framing members, a steel plate or bushing, at least 1/16"
What is the minimum thickness of a
thick, must be installed to cover the area of the wiring. The plate is
nail plate?
intended to protect the wiring from penetration by nails or screws. The
plate is not required when the wiring is installed through holes bored at
least 1-1/4" from the nearest edge of the framing member
What do you fill a conduit with to sealing compound
prevant gas from escaping ?
Circuits classified as life safety automatic switching equipment
branch circuits or critical branch
circuits of emergency electrical
systems in health care facilities must
have:
You are replacing a 20-amp replace the wire with No. 12
receptacle in a bakery and notice a
14 gage wire running from the same
circuit to a light. What should you do
to correct the problem?
A three-phase transformer provides bond metal siding to grounding electrode system
208/120-volt power to a building
with metal siding. What should be
done?
Update
Terms in this set (132)
Question #: 1: When troubleshooting Correct answer: bad capacitor
a motor capacitor, the meter pegs to Additional Notes: If the capacitor were good, the needle would peg to
the right and stays there. What does the right, then slowly drop back down.
this indicate?
Question #: 2: On a 480 V, three- Correct answer: overloaded motor
phase blower motor with auxiliary
contacts and indicators, the push
button start is off due to a thermal
overload. What is the most likely
cause?
7'-6"
When installing a fire alarm system Additional Notes: The top of the device should be at least 7'-6" above
bell or horn, how far above grade the finished floor and at least 6" below the finished ceiling. If the ceiling
should it be mounted? height is too low to allow the recommended mounting heights, the
device can be mounted at a lower height, or on the ceiling.
What is the minimum length of a 8'
grounding rod?
When testing a GFCI trip, probe inductive voltage tester
conductor and fixture ground, use:
On a walk-through of a new home, would need to install 2 outlets
the owner wants you to install an
outlet beside the stove. The counter
top is 48" long and the wall is 6'
away. The contractor
Correct answer: 1/8"
What is the maximum allowed gap
Additional Notes: Plaster, drywall, or plasterboard surfaces must not
allowed around a box in a wall
have gaps or open spaces greater than 1/8" at the edge of a box or
finished with drywall?
fitting.
What is the minimum number of Correct answer: two; one from the emergency electrical system and the
branch circuits required at each other from the normal system
patient bed location?
, Correct answer: when you are reducing vibration and noise on the
When can you have an isolated ground
ground passing through a panel Additional Notes: When installing an isolated ground receptacle the
without connecting it to that panel's insulated equipment grounding conductor is run with the circuit
equipment grounding terminal bar? conductors directly back to the main service disconnect. Metal boxes
and raceways must still be grounded.
Correct answer: the service pit is inadequately ventilated
Which of the following could cause Additional Notes: The entire area of repair garages, up to a level of 18"
a significant increase to the bid above the floor, are Class I, Division 2, locations. Any depression below
amount on a job at an automotive floor level (such as a service pit) is also a Class I, Division 2, location
repair shop? unless it is unvented in which case it may be considered a Class I,
Division 1, location and require special fittings.
What would you use in a capacitive inductor
reactance circuit to balance the
circuit?
Which of the following NEMA rating Correct answer: NEMA 3R
should be used for temporary Additional Notes: Enclosures with a NEMA rating of 3R is designed for
construction power enclosures indoor or outdoor use. Enclosures with ratings of 1, 2, or 12 are designed
outside? for indoor use only.
Correct answer: 103 amps
Additional Notes: To find the amperage of a three-phase motor when
What is the full-load current rating of
you know the horsepower you use a variation of Watt's Law:
a 208-volt, 50-horsepower, three-
I = (horsepower x 746 watts/horsepower) / (E x 1.73)
phase squirrel-cage motor?
I = (50 hp x 746 watts/hp) / (208 volts x 1.73) = 37,300 watts / 360 volts =
103 amps
When connecting conduit in a Correct answer: seal-off fitting
hazardous area, what do you use in
order to prevent the passage of
gasses, vapors, or flames?
When a house heater comes on, Correct answer: bad neutral connection
some lights get bright, others get
dim. What could cause this?
What is the difference between a Correct answer: a grounded conductor is a circuit conductor that is
grounded conductor and a intentionally grounded and a grounding conductor is a conductor that is
grounding conductor? used to connect the grounded circuit to a grounding electrode
Correct answer: press the test button
Additional Notes: All GFCI outlets come with a "test" button that induces
How do you test a GFCI? a small ground. To test, plug in a light, turn it on and press the "test"
button. The button should pop out and the light should go out.
(Sometimes only ONE of these things will happen!)
If the phase-to-neutral voltage in a Correct answer: 4,150 volts
three-phase, Y-connected system is Additional Notes: To find the phase-to-phase voltage in a three-phase
2400 volts, what is the phase-to- system, multiply the phase-to-neutral voltage by the square root of three
phase voltage? (the "three-phase factor"): 2,400 volts x 1.73 = 4,152 volts.
, On a 480 V, three-phase blower Correct answer: internal short
motor with auxiliary contacts and
indicators, a fuse is blown. What is
the most likely cause?
Correct answer: 14
Additional Notes: The number of circuits = total load (VA) / capacity of
each circuit (VA)
A store building measuring 60 ft x 80
The general lighting load for stores is 3 VA per sq ft: (60ft x 80ft) x 3
ft is supplied by a 120/240-volt,
VA/sq ft = 14,400 V A.
three-phase, four-wire system, and
The lighting load for show window is 200 VA per linear ft: 60 ft x 200
has 60 linear feet of show windows.
VA/ft = 12,000 VA
What is the minimum number of two-
Total lighting load = 14,400 VA + 12,000 VA = 26,400 VA x 1.25 (125% for
wire, 20- ampere branch circuits
continuous loads) = 33,000 VA.
required to supply the continuous
Although supplied by a three-phase system, the two-wire, 120-volt
general lighting and show window
branch circuits are single-phase (so you don't need to use the three-
lighting for the building?
phase factor in your calculations).
The capacity of each circuit = 120 V x 20A = 2400 VA
33,000 VA / 2400 VA = 13.75, which rounds up to 14 circuits.
In addition to the type of Correct answer: occupancy
construction, how does the NEC
classify buildings?
Correct answer: 1/16"
Additional Notes: When cable- or raceway-type wiring is installed
through wood framing members, a steel plate or bushing, at least 1/16"
What is the minimum thickness of a
thick, must be installed to cover the area of the wiring. The plate is
nail plate?
intended to protect the wiring from penetration by nails or screws. The
plate is not required when the wiring is installed through holes bored at
least 1-1/4" from the nearest edge of the framing member
What do you fill a conduit with to sealing compound
prevant gas from escaping ?
Circuits classified as life safety automatic switching equipment
branch circuits or critical branch
circuits of emergency electrical
systems in health care facilities must
have:
You are replacing a 20-amp replace the wire with No. 12
receptacle in a bakery and notice a
14 gage wire running from the same
circuit to a light. What should you do
to correct the problem?
A three-phase transformer provides bond metal siding to grounding electrode system
208/120-volt power to a building
with metal siding. What should be
done?
