Electrician: Services - Feeders - Service Disconnect - 230.71 - Maximum Number Location Grouping

What Is It?

1. Service Disconnect: 230.71 refers to the NEC (National Electric Code) section that dictates the maximum number, location, and grouping requirements for service disconnects.
2. This topic is tested on licensing exams for electricians, applied in real-world installations, and audited for compliance with electrical safety standards.

Why Does the Exam Ask This?

The exam asks this to measure the candidate's understanding of electrical safety standards, specifically the requirements for service disconnects to ensure safe and proper electrical installations.

What Do I Need to Know First?

• Understanding of NEC Section 230.71
• Knowledge of electrical safety standards
• Familiarity with service disconnect components

Topic Snapshot

Service Disconnect: 230.71 is a critical topic in the Services & Feeders class for electricians, focusing on the regulations for service disconnects. It matters because it directly impacts electrical safety and compliance with NEC standards.

Exam / Job / Audit Weighting

• Frequency: High
• Difficulty Rating: Intermediate
• Question Type: Multiple-choice, short-answer, and scenario-based questions

Difficulty Level

intermediate

Must-Know Rules, Formulas, Standards, or Principles

1. The maximum number of service disconnects allowed is six.
2. Service disconnects must be grouped and located in a specific area.
3. The location of service disconnects must be within 10 feet of the electric meter.

Misconceptions

1. Believing there is no limit to the number of service disconnects.
2. Thinking service disconnects can be located anywhere.
3. Assuming grouping is not necessary.

Common Mistakes

1. Incorrectly counting the number of service disconnects.
2. Improperly locating service disconnects.
3. Failing to group service disconnects correctly.

The Common Trap

The common trap is misunderstanding the specific requirements for the location and grouping of service disconnects, often leading to non-compliance with NEC standards.

Terms to Remember

1. Service Disconnect: A device or set of devices used to disconnect the electrical service.
2. NEC (National Electric Code): A set of standards for electrical installations.
3. Grouping: The requirement that service disconnects be located together.
4. Maximum Number: The limit of six service disconnects.
5. Location: The requirement that service disconnects be within 10 feet of the electric meter.

Step-by-Step Process

1. Determine the number of service disconnects needed.
2. Ensure the service disconnects are grouped together.
3. Verify the location of service disconnects is within 10 feet of the electric meter.

Exam Answer Builder

• 1-mark Question: What is the maximum number of service disconnects allowed by NEC Section 230.71?
• Example: What is the maximum number of service disconnects?
• Options: A) 3, B) 6, C) 10, D) Unlimited
• Correct Answer: B) 6

• Key Tip: Remember the specific limit set by NEC Section 230.71.

• 2-mark Question: Describe the requirements for grouping and locating service disconnects.

• Example: What are the grouping and location requirements for service disconnects?

• Key Tip: Mention both the grouping and the 10-foot rule.

• 5-mark Question: A commercial building has two electric meters, each requiring a service disconnect. Discuss the NEC Section 230.71 requirements for these service disconnects, including the maximum number, grouping, and location.

• Example: Discuss the NEC requirements for service disconnects in a commercial building with multiple meters.

• Key Tip: Address all three aspects: maximum number, grouping, and location.

• Case Study or Scenario-based Question: An inspector finds that a building has seven service disconnects, not grouped, and located 15 feet from the electric meter. What are the NEC violations?

• Example: Identify NEC violations in a given scenario.
• Key Tip: Identify violations based on the maximum number, grouping, and location requirements.

This vs That

This topic is often confused with requirements for load centers or panelboards, but it specifically addresses service disconnects.

Time-Saver Hack

A quick way to remember the requirements is to use the mnemonic "6-Group-10": six service disconnects maximum, grouped together, and within 10 feet of the electric meter.

Mini Scenarios

• Basic: A residential electrician must install a single service disconnect. What NEC section must they refer to?
• What is happening: Installation of a single service disconnect.

• What to notice: Compliance with NEC Section 230.71.

• Applied: A commercial building has five electric meters. How many service disconnects are allowed, and how should they be arranged?

• What is happening: Multiple service disconnects in a commercial setting.

• What to notice: Maximum number and grouping requirements.

• Tricky: An inspector finds a service disconnect located 12 feet from the electric meter. Is this compliant?

• What is happening: Potential non-compliance with location requirements.
• What to notice: The 10-foot rule.

Diagnostic MCQ Bank

Q1 [Easy]

Question: What is the maximum number of service disconnects allowed by NEC Section 230.71? Options: A) 3 B) 6 C) 10 D) Unlimited Correct Answer: B) 6 Explanation: NEC Section 230.71 specifies a maximum of six service disconnects. Why the correct answer is right: It directly answers the question based on NEC standards. Why the trap option is tempting: Option D) Unlimited seems incorrect but might tempt those unfamiliar with the code.

Q2 [Easy]

Question: Where must service disconnects be located according to NEC Section 230.71? Options: A) Within 5 feet of the electric meter B) Within 10 feet of the electric meter C) At the electrical panel D) Anywhere on the premises Correct Answer: B) Within 10 feet of the electric meter Explanation: NEC Section 230.71 requires service disconnects to be located within 10 feet of the electric meter. Why the correct answer is right: It matches the NEC requirement. Why the trap option is tempting: Option D) Anywhere on the premises seems incorrect but might tempt those unfamiliar with specific NEC requirements.

Q3 [Easy]

Question: What is required for the grouping of service disconnects? Options: A) They must be scattered throughout the building B) They must be grouped together C) They can be located in separate areas D) Grouping is not required Correct Answer: B) They must be grouped together Explanation: NEC Section 230.71 mandates that service disconnects must be grouped. Why the correct answer is right: It directly answers the question based on NEC standards. Why the trap option is tempting: Option A) They must be scattered throughout the building seems obviously incorrect but might confuse some.

Q4 [Medium]

Question: A building has two service disconnects. Are these compliant with NEC Section 230.71 regarding the maximum number? Options: A) Yes, they are compliant B) No, they exceed the maximum C) It depends on the location D) Only if grouped Correct Answer: A) Yes, they are compliant Explanation: Two service disconnects are below the maximum of six allowed. Why the correct answer is right: It directly answers the question based on NEC standards. Why the trap option is tempting: Option B) No, they exceed the maximum might tempt those who misremember the code.

Q5 [Medium]

Question: What NEC section deals with the maximum number, location, and grouping of service disconnects? Options: A) Section 230.70 B) Section 230.71 C) Section 230.72 D) Section 230.73 Correct Answer: B) Section 230.71 Explanation: NEC Section 230.71 specifically addresses these requirements. Why the correct answer is right: It matches the NEC section directly related to the question. Why the trap option is tempting: Other sections might seem relevant but are not directly related.

Q6 [Medium]

Question: Can service disconnects be located in a junction box? Options: A) Yes, if approved for the purpose B) No, they must be in a separate enclosure C) It depends on the type of disconnect D) Only if grouped Correct Answer: A) Yes, if approved for the purpose Explanation: NEC allows service disconnects in approved enclosures, which can include junction boxes under certain conditions. Why the correct answer is right: It considers NEC flexibility in enclosure types. Why the trap option is tempting: Option B) No, they must be in a separate enclosure might seem correct but overlooks NEC allowances.

Q7 [Medium]

Question: What is a common violation regarding service disconnects? Options: A) Exceeding the maximum number B) Improper grouping C) Incorrect location D) All of the above Correct Answer: D) All of the above Explanation: All listed options are common violations. Why the correct answer is right: It encompasses all potential violations. Why the trap option is tempting: Options A, B, or C might seem individually correct but do not cover all violations.

Q8 [Hard]

Question: A building has six service disconnects. Is this compliant with NEC Section 230.71? Options: A) Yes, it meets the maximum requirement B) No, it exceeds the maximum C) It depends on the grouping D) Only if located correctly Correct Answer: A) Yes, it meets the maximum requirement Explanation: Six service disconnects exactly meet the maximum allowed. Why the correct answer is right: It directly answers based on NEC standards. Why the trap option is tempting: Option B) No, it exceeds the maximum might tempt those who misremember the maximum.

Q9 [Hard]

Question: What should be done if a service disconnect is located 11 feet from the electric meter? Options: A) Move it to within 10 feet B) Leave it as is C) Group it with other disconnects D) Replace the disconnect Correct Answer: A) Move it to within 10 feet Explanation: NEC requires service disconnects to be within 10 feet of the electric meter. Why the correct answer is right: It directly addresses the NEC requirement. Why the trap option is tempting: Option B) Leave it as is might seem acceptable but violates NEC standards.

Q10 [Hard]

Question: A service disconnect is installed but not grouped with others. What is the issue? Options: A) It exceeds the maximum number B) It is not located within 10 feet of the meter C) It does not comply with grouping requirements D) It is not a violation Correct Answer: C) It does not comply with grouping requirements Explanation: NEC Section 230.71 requires service disconnects to be grouped. Why the correct answer is right: It directly addresses the NEC requirement. Why the trap option is tempting: Option D) It is not a violation might seem correct but overlooks NEC grouping requirements.

Real-World Patterns

1. Residential installations often involve a single service disconnect.
2. Commercial buildings may have multiple service disconnects, requiring careful grouping and location.
3. Industrial settings frequently involve complex electrical systems with multiple service disconnects.

30-Second Cheat Sheet

1. Maximum of six service disconnects.
2. Service disconnects must be grouped.
3. Location within 10 feet of the electric meter.
4. NEC Section 230.71 governs these requirements.
5. Compliance ensures electrical safety and avoids violations.

Related Concepts

1. NEC Section 230.70 - Service Entrance
2. NEC Section 230.72 - Disconnecting Means
3. NEC Section 230.73 - Rating of Service Disconnects

Verified Source List

1. National Electric Code (NEC) Section 230.71
2. NFPA (National Fire Protection Association) NEC Handbook
3. Local electrical inspection authority guidelines