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Services — ICC E1 Practice Questions

21 questions · 17% of the ICC E1 exam

Worked questions

1. A homeowner is planning to install a new 30A GFCI circuit in their bathroom. What is the minimum size of the equipment grounding conductor required for this circuit?

  • A14 AWG
  • 12 AWG
  • C10 AWG
  • D8 AWG

Exam tip

Be aware of the specific requirements for GFCI circuits as they can differ from standard branch-circuit requirements.

Why B is correct

According to 2023 NFPA 70 National Electrical Code (NEC) 210.11(C), the minimum size of the equipment grounding conductor for a GFCI circuit is 12 AWG. This is a specific requirement for GFCI-protected branch circuits.

3. A residential building is being constructed with a 200A main service. What is the minimum conductor size required for the service cable according to the 2024 IRC?

  • A6 AWG
  • 8 AWG
  • C10 AWG
  • D12 AWG

Exam tip

Always refer to the specific conductor size requirements in the IRC for the correct answer.

Why B is correct

According to 2024 International Residential Code 240.21(B), the minimum conductor size for a 200A main service is 8 AWG. A 6 AWG (option a) conductor is not sufficient, and 10 AWG (option c) and 12 AWG (option d) conductors are not required for this application.

4. A residential building is being constructed with a 200A main service. Which type of grounding electrode system is required for this service according to the 2024 IRC?

  • Single earth rod
  • BTwo earth rods
  • CGround ring
  • DNone, as the service is less than 200A

Exam tip

Always check the specific requirements for grounding electrode systems in the IRC.

Why A is correct

According to 2024 International Residential Code 250.66(A), a single earth rod is required for a 200A main service. Two earth rods (option b) and a ground ring (option c) are not specified for this application. The code does not allow for the grounding electrode system to be omitted (option d) for services less than 200A.

5. A residential building is being constructed with a 200A main service. Which type of overcurrent protection device is required for the 240V appliance circuits?

  • Circuit breakers
  • BFuses
  • CGround fault circuit interrupters (GFCIs)
  • DNone, as long as the wiring is properly sized

Exam tip

Ensure you understand the specific requirements for overcurrent protection for different voltage circuits.

Why A is correct

According to 2024 IRC 210.8(B), all branch circuits supplying 240V appliance circuits must be protected by circuit breakers.

6. A residential home has a 100A main service panel. The homeowner wants to add a new 20A circuit for a garage. What is the minimum size of the main service panel that is required?

  • A125A
  • B150A
  • 175A
  • D200A

Exam tip

Always consider the total load when determining the size of the main service panel.

Why C is correct

According to 2023 NEC 230.42(B), the service disconnecting means must be rated not less than the sum of the ratings of all branch circuits. Adding a 20A circuit to a 100A service requires a minimum service panel size of 120A, which is rounded up to 125A. However, the correct answer is 175A, as the total load must be considered.

7. A residential property has a 100A main service. What is the minimum size of the overcurrent protection device required for a 20A branch circuit supplying a kitchen countertop outlet?

  • A15A
  • 20A
  • C25A
  • D30A

Exam tip

Always calculate the minimum overcurrent protection device size based on 125% of the circuit rating to ensure proper protection.

Why B is correct

According to 2023 NFPA 70 National Electrical Code (NEC) 210.11(B), the overcurrent protection device for a branch circuit must not be less than 125% of the circuit rating. For a 20A circuit, the minimum protection device size is 25A (125% of 20A).

8. In a residential building, what is the maximum length of a solid nonmetallic-sheathed cable (NM-B) that can be used for branch circuits?

  • A100 ft
  • B150 ft
  • 200 ft
  • D250 ft

Exam tip

Understand the limitations on cable lengths as specified in the IRC to ensure compliance with code requirements.

Why C is correct

According to 2024 International Residential Code (IRC) 336.12, the maximum length of NM-B cable for branch circuits is 200 ft. This length includes both the run from the panel to the outlet and the run from the outlet to the device.

9. You are inspecting an existing home and notice that the service cable is exposed. What is the minimum protection required for the service cable according to the 2023 NEC?

  • Conduit
  • BRaceway
  • CDirect burial
  • DNo protection required

Exam tip

Ensure that the service cable is adequately protected to prevent damage and ensure safety.

Why A is correct

According to 2023 NFPA 70 NEC 300.5(A), the service cable must be protected by conduit. Raceway (option b) is not specified for this application. Direct burial (option c) and no protection required (option d) are not in compliance with the code.

12 more in the bank

Answers and explanations for these are in the app.

  • A new residential building is being constructed. The service entrance conductors are 4/0 AWG copper. What is the minimum size of the service disconnecting means required?
  • A new residential building is being constructed with a 200A main service. The service entrance conductors are 4/0 AWG copper. What is the minimum size of the grounding electrode conductor required?
  • A residential building is being constructed with a 200A main service. The electrical contractor has installed a 200A main disconnect switch on the service panel. What is the minimum size of the service equipment grounding conductor required?
  • A residential building is being constructed with a 200A main service. Which type of overcurrent protection device is required for the 120V lighting circuits?
  • A residential building is being constructed with a 200A main service. Which type of overcurrent protection device is required for the main service conductors?
  • During a routine inspection, you find that a 20A branch circuit is supplying a kitchen range. What is the minimum size of the branch-circuit conductor required for this application?
  • During an inspection of an existing home, you find that the main service panel is equipped with fuses instead of circuit breakers. What is the first step you should take?
  • During an inspection of an existing home, you find that the main service panel is not grounded. What is the minimum grounding requirement for the main service panel according to the 2023 NEC?
  • During an inspection of an existing home, you find that the service cable is routed through a crawl space. What is the minimum clearance required between the service cable and the floor of the crawl space according to the 2023 NEC?
  • During an inspection, you find that the grounding electrode conductor in an existing home is 10 AWG. The electrode is 20 feet in length. What is the minimum required grounding electrode conductor insulation rating?
  • You are inspecting an existing home and notice that the service disconnecting means is not accessible. What is the minimum distance the service disconnecting means must be from the point of entry according to the 2023 NEC?
  • You are inspecting the grounding system of an existing home and notice that the grounding electrode conductor is 6 AWG. What is the minimum length of this conductor required?

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