NEC 230.71: Service Disconnecting Means — The “Six Disconnect Rule” Explained

One of the most commonly misunderstood—and heavily enforced—sections of the NEC is 230.71, often referred to as the “six disconnect rule.” For commercial electrical contractors, misunderstanding this rule can result in failed inspections, redesigns, or costly rework.

NEC 230.71 governs how many service disconnects are permitted, how they must be grouped, and how emergency responders can safely shut down power to a building.

👉 If you’re new to NEC structure, start with our NEC Overview: What It Is and Why It Matters for foundational context.
👉 For distribution fundamentals, review Services and Feeders Explained before diving into this service-specific rule.

 

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What NEC 230.71 Requires

NEC 230.71(A) states that a service is permitted to have no more than six service disconnecting means for each set of service conductors.

In plain language:

• You may have up to six disconnects

• Those disconnects must disconnect all ungrounded conductors

• They must be grouped and readily accessible

This rule exists so emergency personnel can kill power quickly without searching through a building.

 

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Why the “Six Disconnect Rule” Exists

Before modern main breakers, buildings often used multiple switches to disconnect power. NEC 230.71 limits this complexity to reduce risk during:

• Fires

• Electrical emergencies

• Maintenance work

If more than six disconnects were allowed, emergency responders could lose precious time trying to shut down power.

 

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Grouping Requirements (Critical for Inspections)

NEC 230.71 requires that all service disconnects be grouped in one location.

That means:

• ❌ No scattered disconnects throughout the building

• ❌ No disconnects hidden behind equipment

• ✅ All service disconnects in one readily accessible area

Inspectors are extremely strict on this point.

 

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NEC 230.71 vs NEC 225.31 (Very Common Confusion)

This is where contractors often get tripped up:

👉 If the conductors are service conductors, NEC 230 applies.
👉 If the building is fed by feeders, NEC 225 applies.

For feeder-fed buildings, review NEC 225.31: Disconnecting Means for Buildings.

 

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Interaction with Feeder Rules

Once power passes the service disconnects:

• NEC 215.2 governs feeder sizing

• NEC 215.10 may require ground-fault protection

• NEC 220.42 & 220.87 determine load calculations

That’s why service disconnect decisions must align with the rest of the system.

Relevant references:

• NEC 215.2 – Feeder Conductor Sizing

• NEC 215.10 – Ground-Fault Protection of Feeders

• NEC 220.87 – Determining Existing Loads

 

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Common Contractor Mistakes

❌ Installing more than six service disconnects
❌ Mislabeling feeder disconnects as service disconnects
❌ Separating disconnects across multiple rooms
❌ Failing to clearly identify service disconnects
❌ Confusing tenant disconnects with service disconnects

These issues almost always result in inspection failures.

 

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Labeling Is Not Optional

NEC 110.22 requires that service disconnects be clearly and durably labeled.

Labels should identify:

• Service disconnect location

• Equipment served

• Voltage and hazard warnings

✅ At Print Pro, we provide NEC-compliant service disconnect labels, placards, and arc-flash warnings that inspectors expect to see on commercial service equipment.

 

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Pro Tips for Contractors

• When in doubt, install a single main disconnect — many AHJs prefer it.

• Confirm early whether conductors are service or feeder — it changes everything.

• Keep service disconnects clearly grouped and visible.

• Label service disconnects during rough-in, not at final.

• Coordinate with the AHJ on multi-tenant buildings — interpretations vary.

 

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Conclusion

NEC 230.71 exists to ensure service power can be disconnected quickly, clearly, and safely. For contractors, compliance isn’t just about counting disconnects—it’s about proper grouping, identification, and coordination with feeder systems.