6.2 Service Disconnecting Means

Service Disconnects on the Prov Outline

Within the 8-item Services/Feeders/OCP block, disconnect questions are high yield because the answers are section-specific numbers and locations. This section drills Article 230 Parts V–VII disconnecting means and related service-equipment rules that Arkansas Journeyman candidates must look up cleanly under a 3-hour clock.

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Required Disconnect — 230.70

230.70 requires means to disconnect all ungrounded conductors from the service conductors. Key location rules in 230.70(A):

• The disconnecting means must be readily accessible.
• It must be located either outside the building or structure, or inside nearest the point of entrance of the service conductors.
• It must not be installed in bathrooms.

“Nearest the point of entrance” is a Code judgment phrase inspectors fight about in the field; on the exam, prefer the option that places the disconnect outside or immediately inside at the entrance rather than deep in the building after a long unprotected service-entrance run.

Marking: Service equipment must be marked to identify it as suitable for use as service equipment (230.66), and the disconnect must be permanently marked to identify it as a service disconnect where required by the section/system rules you open.

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Maximum Number of Disconnects — 230.71 (NEC 2023)

This is where older study notes fail people. Learn the 2023 structure:

230.71(A) — General

Each service is permitted to have only one disconnecting means unless 230.71(B) permits more.

230.71(B) — Two to six service disconnecting means

Where permitted, two to six service disconnects may be used for each service (or for each set of service-entrance conductors allowed by certain 230.40 exceptions). Those disconnects must be arranged as one of the listed configurations, such as:

• Separate enclosures, each with a main service disconnect
• Panelboards with a main service disconnect in each enclosure
• Switchboard/switchgear arrangements with barriers so each vertical section has only one service disconnect
• Other configurations expressly listed in 230.71(B)

Critical 2020/2023 change: You generally cannot install up to six breakers as service disconnects in a single enclosure the way older Code cycles allowed. If a stem shows six breakers in one service panelboard enclosure as the only service disconnects, treat that as a red flag under current 230.71 — open the section and match the permitted configurations.

Still true: The practical ceiling remains six operations of the hand for the permitted multi-disconnect arrangements, and 230.72 still requires grouping and marking so the load served is identified.

Grouping — 230.72

Service disconnects for each service must be grouped. Additional disconnects for fire pumps, emergency systems, and similar may have special placement/marking rules — read 230.72 carefully when the stem mentions fire pump or emergency systems.

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Rating of the Service Disconnect — 230.79

230.79 sets minimum ratings. Highest-frequency dwelling fact:

• 230.79(C) One-Family Dwelling: The service disconnecting means must have a rating of not less than 100 amperes, 3-wire.

Other occupancy rows exist (for example, smaller ratings for limited loads under other subsections). On Prov, if the stem says one-family dwelling service disconnect minimum, 100 A is the number to verify — not 60 A folklore from old small-service eras.

Also connect this to load calculations: Article 220 may drive a larger required service; 230.79 is a floor, not a ceiling.

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Emergency Disconnects for Dwellings — 230.85

230.85 (NEC 2020 introduced; still critical in 2023) requires an emergency disconnect for one- and two-family dwelling units:

• Readily accessible outdoor location
• Marked so first responders can identify it (markings such as EMERGENCY DISCONNECT / service disconnect identification per the section’s options)
• Short-circuit current rating adequate for available fault current

The emergency disconnect may be the service disconnect or another compliant arrangement described in 230.85. Exam stems often ask where it must be (outdoors / readily accessible) and what marking is required — not obscure utility company preferences.

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Surge Protection for Dwelling Services — 230.67

230.67 requires all services supplying dwelling units to be provided with a Type 1 or Type 2 SPD. The SPD may be an integral part of the service equipment or located immediately adjacent. Replacement service equipment for dwellings also triggers the requirement per the section’s scope.

If a stem asks what is required when installing new dwelling service equipment, do not forget SPD — it is easy to over-focus on the 100 A disconnect and miss 230.67.

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Ground-Fault Protection of Equipment — 230.95

230.95 is a classic large-service item (also appears in Arkansas practice banks):

Ground-fault protection of equipment is required for solidly grounded wye electrical services of more than 150 volts to ground that have a service disconnect rated 1000 amperes or more.

Key exam facts to verify in the section:

• Threshold: 1000 A service disconnect rating (not “any service over 480 V”)
• System type: solidly grounded wye, more than 150 V to ground (e.g., 277/480 V wye)
• Maximum setting commonly referenced: ground-fault protection set to operate at not more than 1200 A (confirm exact performance requirements in 230.95)
• Exceptions exist (for example, certain continuous industrial process provisions) — open them only when the stem invokes them

Trap: 800 A or 600 A disconnects do not meet the 1000 A trigger even on 480Y/277 V systems.

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Overcurrent Protection Location — 230.91

230.91 requires the service overcurrent device to be an integral part of the service disconnecting means or located immediately adjacent thereto. Unprotected service conductors on the supply side of the service OCPD must be kept as short as practicable and installed per Article 230 — this is why “panel in the middle of the house with a long indoor service-entrance run” is a Code smell.

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Simultaneous Opening and Grounded Conductors

Service disconnects must open all ungrounded conductors of the service simultaneously as required by 230.74 / related rules. The grounded conductor (neutral) is not required to be switched by the service disconnect in the same way, but means must exist to disconnect the grounded conductor from the premises wiring where required (230.75). Do not confuse “must disconnect the neutral with the main” folklore with the actual section text.

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Exam Workflow — Disconnect Stems

1. Identify occupancy: one-family dwelling vs other.
2. Ask location: outside / nearest entrance / bathroom (bathroom = no).
3. Ask quantity: one vs two-to-six under 230.71(B) configurations.
4. Ask rating floor: 100 A dwelling?
5. Ask extras: 230.85 emergency disconnect? 230.67 SPD? 230.95 GFP?

That sequence prevents mixing a dwelling emergency-disconnect question with a 1000 A GFP commercial question.