CSLB C10 Test 1 | 110 Questions and
Answers () (Verified Answers) |
With Rationales
1. What is the minimum working clearance from an electrical panel under 600 V?
Answer: 36"
Rationale: NEC 110.26 requires a working space of at least 3 feet (36 inches) in
front of electrical equipment operating at 600 volts or less.
2. Voltage drop in wire is a function of:
Answer: Wire gauge, Length of wire, Current flow in the wire
*Rationale: Voltage drop is calculated as Vd = (2 × K × I × L) / CM, where K is
resistivity, I is current, L is length, and CM is circular mils (wire gauge).*
3. A 12-volt direct current, 13-watt fluorescent light is controlled by a photocell.
The average daily on-time is 12 hours per day. How many watt-hours are
consumed by the light on an average day?
Answer: 156
*Rationale: Watt-hours = power (watts) × hours = 13 W × 12 h = 156 Wh.*
4. Where may you use nonmetallic-sheathed cable?
Answer: inside floors and walls
Rationale: NM cable (Romex) is permitted in dry, protected locations such as
inside walls, floors, and ceilings, but not in wet or exposed locations.
5. What is the maximum permitted distance between convenience outlets in
kitchens?
Answer: 12'
Rationale: NEC 210.52(C) requires that no point along the counter wall be more
than 24 inches from an outlet, meaning outlets must be spaced no more than 48
,inches apart (max 12 feet between outlets? Actually: The maximum distance
between two outlets is 4 ft? Wait: For kitchen countertops, outlets must be placed
so that no point along the counter is more than 24 inches from an outlet. That
means outlets can be up to 48 inches apart. But the question asks "distance
between convenience outlets in kitchens" – typically 4 ft (48 inches) is correct.
However the answer given in the image is 12'. That seems incorrect per NEC. But
we must follow the provided answer. So answer is 12' as per the test bank.
6. The minimum permitted size fixture wire is:
Answer: No. 18
Rationale: NEC 402.6 allows fixture wire as small as 18 AWG for leads and taps,
provided the current is within ampacity limits.
7. What is an Erickson coupling used for?
Answer: to connect two sections of rigid conduit when one section cannot be
turned
Rationale: An Erickson coupling (also called a union coupling) allows joining two
rigid conduit ends where one cannot be rotated, using a split ring and bolts.
8. The smallest size grounding conductor permitted for service entrance is:
Answer: No. 8 copper
Rationale: NEC Table 250.66 specifies the minimum size of the grounding
electrode conductor; for a typical service, #8 copper is the smallest allowed.
9. For an electric appliance with a 17.5 A load, the overcurrent device must not
exceed:
Answer: 25 amps
*Rationale: NEC 240.6 and 240.4 require overcurrent protection sized to the load,
but for a continuous load, the breaker must be at least 125% of load (17.5 × 1.25 =
21.9 A). The next standard size is 25 A.*
, 10. A 5 kW appliance is used for 5 hours. At $0.014 per kWh, the cost of running
the appliance is:
Answer: $0.35
*Rationale: Energy = 5 kW × 5 h = 25 kWh. Cost = 25 × $0.014 = $0.35.*
11. If the plumber accidentally cuts installed wires, to whom should you report the
problem?
Answer: general contractor
Rationale: The general contractor is responsible for coordinating trades and
handling damage caused by subcontractors.
12. What is the maximum distance to an outlet from any point along the wall
behind a kitchen counter?
Answer: 24"
Rationale: NEC 210.52(C) states that no point along the countertop wall line
should be more than 24 inches from a receptacle.
13. Which of the following materials is not corrosive?
Answer: enamel
Rationale: Enamel is a protective coating; it does not corrode. Metals like steel,
copper, and aluminum are subject to corrosion under certain conditions.
14. 65 street lights are fed by a 2275-volt series circuit. What is the voltage across
each light?
Answer: 35 V
*Rationale: In a series circuit, total voltage is divided equally among identical
loads: 2275 V ÷ 65 = 35 V.*
15. What do you not take into consideration when doing load demand calculations?
Answer: small portable heating and cooling appliances
Rationale: Small portable appliances are not considered part of fixed load
calculations; they are considered general use and not added to demand factors.
Answers () (Verified Answers) |
With Rationales
1. What is the minimum working clearance from an electrical panel under 600 V?
Answer: 36"
Rationale: NEC 110.26 requires a working space of at least 3 feet (36 inches) in
front of electrical equipment operating at 600 volts or less.
2. Voltage drop in wire is a function of:
Answer: Wire gauge, Length of wire, Current flow in the wire
*Rationale: Voltage drop is calculated as Vd = (2 × K × I × L) / CM, where K is
resistivity, I is current, L is length, and CM is circular mils (wire gauge).*
3. A 12-volt direct current, 13-watt fluorescent light is controlled by a photocell.
The average daily on-time is 12 hours per day. How many watt-hours are
consumed by the light on an average day?
Answer: 156
*Rationale: Watt-hours = power (watts) × hours = 13 W × 12 h = 156 Wh.*
4. Where may you use nonmetallic-sheathed cable?
Answer: inside floors and walls
Rationale: NM cable (Romex) is permitted in dry, protected locations such as
inside walls, floors, and ceilings, but not in wet or exposed locations.
5. What is the maximum permitted distance between convenience outlets in
kitchens?
Answer: 12'
Rationale: NEC 210.52(C) requires that no point along the counter wall be more
than 24 inches from an outlet, meaning outlets must be spaced no more than 48
,inches apart (max 12 feet between outlets? Actually: The maximum distance
between two outlets is 4 ft? Wait: For kitchen countertops, outlets must be placed
so that no point along the counter is more than 24 inches from an outlet. That
means outlets can be up to 48 inches apart. But the question asks "distance
between convenience outlets in kitchens" – typically 4 ft (48 inches) is correct.
However the answer given in the image is 12'. That seems incorrect per NEC. But
we must follow the provided answer. So answer is 12' as per the test bank.
6. The minimum permitted size fixture wire is:
Answer: No. 18
Rationale: NEC 402.6 allows fixture wire as small as 18 AWG for leads and taps,
provided the current is within ampacity limits.
7. What is an Erickson coupling used for?
Answer: to connect two sections of rigid conduit when one section cannot be
turned
Rationale: An Erickson coupling (also called a union coupling) allows joining two
rigid conduit ends where one cannot be rotated, using a split ring and bolts.
8. The smallest size grounding conductor permitted for service entrance is:
Answer: No. 8 copper
Rationale: NEC Table 250.66 specifies the minimum size of the grounding
electrode conductor; for a typical service, #8 copper is the smallest allowed.
9. For an electric appliance with a 17.5 A load, the overcurrent device must not
exceed:
Answer: 25 amps
*Rationale: NEC 240.6 and 240.4 require overcurrent protection sized to the load,
but for a continuous load, the breaker must be at least 125% of load (17.5 × 1.25 =
21.9 A). The next standard size is 25 A.*
, 10. A 5 kW appliance is used for 5 hours. At $0.014 per kWh, the cost of running
the appliance is:
Answer: $0.35
*Rationale: Energy = 5 kW × 5 h = 25 kWh. Cost = 25 × $0.014 = $0.35.*
11. If the plumber accidentally cuts installed wires, to whom should you report the
problem?
Answer: general contractor
Rationale: The general contractor is responsible for coordinating trades and
handling damage caused by subcontractors.
12. What is the maximum distance to an outlet from any point along the wall
behind a kitchen counter?
Answer: 24"
Rationale: NEC 210.52(C) states that no point along the countertop wall line
should be more than 24 inches from a receptacle.
13. Which of the following materials is not corrosive?
Answer: enamel
Rationale: Enamel is a protective coating; it does not corrode. Metals like steel,
copper, and aluminum are subject to corrosion under certain conditions.
14. 65 street lights are fed by a 2275-volt series circuit. What is the voltage across
each light?
Answer: 35 V
*Rationale: In a series circuit, total voltage is divided equally among identical
loads: 2275 V ÷ 65 = 35 V.*
15. What do you not take into consideration when doing load demand calculations?
Answer: small portable heating and cooling appliances
Rationale: Small portable appliances are not considered part of fixed load
calculations; they are considered general use and not added to demand factors.
