NEC 430.101–430.113 — Disconnecting Means (Part IX)

What Part IX is (and where it sits in the motor series)

Articles 38–41 of this series covered the motor circuit and the controller: conductors and branch protection (430.22/430.52), overload (430.32/430.36), control circuits (430.72/430.75), and the controller device itself (Part VII). Part IX is the disconnect — the device that takes the circuit and the controller dead for service, and it answers three separate questions: where (430.102), what kind of device (430.109), and what rating (430.110). One governing sentence: Part IX is intended to require disconnecting means capable of disconnecting motors and controllers from the circuit (430.101).

The section sequence in both the 2017 and 2023 code is 430.101, 430.102, 430.103, 430.104, 430.105, 430.107, 430.108, 430.109, 430.110, 430.111, 430.112, 430.113 — note the gap at 430.106, which does not exist in either edition (verified on disk). Part X (430.120 onward) applies Parts I–IX to adjustable-speed drives and is a separate article topic.

430.101 — General

Part IX is intended to require disconnecting means capable of disconnecting motors and controllers from the circuit.

430.102 — Location (in sight, lockable, the 2023 motor-disconnect exceptions)

(A) Controller. An individual disconnecting means shall be provided for each controller and shall disconnect the controller. The disconnecting means shall be located in sight from the controller location.

Exception No. 1: For motor circuits over 1000 volts, nominal, a controller disconnecting means lockable in accordance with 110.25 shall be permitted to be out of sight of the controller, provided that the controller is marked with a warning label giving the location of the disconnecting means.

Exception No. 2: A single disconnecting means shall be permitted for a group of coordinated controllers that drive several parts of a single machine or piece of apparatus. The disconnecting means shall be located in sight from the controllers, and both the disconnecting means and the controllers shall be located in sight from the machine or apparatus.

Exception No. 3: The disconnecting means shall not be required to be in sight from valve actuator motor (VAM) assemblies containing the controller where such a location introduces additional or increased hazards to persons or property and conditions (a) and (b) are met. (a) The valve actuator motor assembly is marked with a warning label giving the location of the disconnecting means. (b) The disconnecting means is lockable in accordance with 110.25.

(B) Motor. A disconnecting means shall be provided for a motor in accordance with (B)(1) or (B)(2).

(1) Separate Motor Disconnect. A disconnecting means for the motor shall be located in sight from the motor location and the driven machinery location.

(2) Controller Disconnect. The controller disconnecting means required in accordance with 430.102(A) shall be permitted to serve as the disconnecting means for the motor if it is in sight from the motor location and the driven machinery location.

Exception to (1) and (2): The disconnecting means for the motor shall not be required under either condition (a) or condition (b), which follow, provided that the controller disconnecting means required in 430.102(A) is lockable in accordance with 110.25.

(a) Where such a location of the disconnecting means for the motor is impracticable or introduces additional or increased hazards to persons or property. Informational Note: Some examples of increased or additional hazards include, but are not limited to, motors rated in excess of 100 hp, multimotor equipment, submersible motors, motors associated with adjustable speed drives, and motors located in hazardous (classified) locations.

(b) In industrial installations, with written safety procedures, where conditions of maintenance and supervision ensure that only qualified persons service the equipment. Informational Note: For information on lockout/tagout procedures, see NFPA 70E-2015, Standard for Electrical Safety in the Workplace.

The location logic has two layers. Layer one is the controller disconnect: one per controller, in sight of the controller. Layer two is the motor disconnect: in sight of the motor AND the driven machinery — because the person operating the machine is who needs to be able to throw the disconnect, not just the person standing at the starter. The controller disconnect may serve both layers if it is in sight of all three points (controller, motor, machinery). And the 2023-relevant escape hatch — lockable controller disconnect per 110.25 → no separate motor disconnect — is what makes padlocked starter-door switches acceptable on the big motors where a machinery-level disconnect would be impracticable.

430.103 — Operation (all poles, no auto-close)

The disconnecting means shall open all ungrounded supply conductors and shall be designed so that no pole can be operated independently. The disconnecting means shall be permitted in the same enclosure with the controller. The disconnecting means shall be designed so that it cannot be closed automatically.

Informational Note: See 430.113 for equipment receiving energy from more than one source.

430.104 — To Be Indicating

The disconnecting means shall plainly indicate whether it is in the open (off) or closed (on) position.

430.105 — Grounded Conductors (one pole permitted, with a design condition)

One pole of the disconnecting means shall be permitted to disconnect a permanently grounded conductor, provided the disconnecting means is designed so that the pole in the grounded conductor cannot be opened without simultaneously disconnecting all conductors of the circuit.

430.107 — Readily Accessible

At least one of the disconnecting means shall be readily accessible.

430.108 — Every Disconnecting Means (the compliance sweep)

Every disconnecting means in the motor circuit between the point of attachment to the feeder or branch circuit and the point of connection to the motor shall comply with the requirements of 430.109 and 430.110.

430.109 — Type (the seven permitted devices, plus the small-motor relaxations)

The disconnecting means shall be a type specified in 430.109(A), unless otherwise permitted in 430.109(B) through (G), under the conditions specified.

(A) General.

(1) Motor Circuit Switch. A listed motor-circuit switch rated in horsepower.

(2) Molded Case Circuit Breaker. A listed molded case circuit breaker.

(3) Molded Case Switch. A listed molded case switch.

(4) Instantaneous Trip Circuit Breaker. An instantaneous trip circuit breaker that is part of a listed combination motor controller.

(5) Self-Protected Combination Controller. Listed self-protected combination controller.

(6) Manual Motor Controller. Listed manual motor controllers additionally marked "Suitable as Motor Disconnect" shall be permitted as a disconnecting means where installed between the final motor branch-circuit short-circuit protective device and the motor. Listed manual motor controllers additionally marked "Suitable as Motor Disconnect" shall be permitted as disconnecting means on the line side of the fuses permitted in 430.52(C)(5). In this case, the fuses permitted in 430.52(C)(5) shall be considered supplementary fuses, and suitable branch-circuit short-circuit and ground-fault protective devices shall be installed on the line side of the manual motor controller additionally marked "Suitable as Motor Disconnect."

(7) System Isolation Equipment. System isolation equipment shall be listed for disconnection purposes. System isolation equipment shall be installed on the load side of the overcurrent protection and its disconnecting means. The disconnecting means shall be one of the types permitted by 430.109(A)(1) through (A)(3).

(B) Stationary Motors of 1/8 Horsepower or Less. For stationary motors of 1/8 hp or less, the branch-circuit overcurrent device shall be permitted to serve as the disconnecting means.

(C) Stationary Motors of 2 Horsepower or Less. For stationary motors rated at 2 hp or less and 300 volts or less, the disconnecting means shall be permitted to be one of the devices specified in (1), (2), or (3):

(1) A general-use switch having an ampere rating not less than twice the full-load current rating of the motor

(2) On ac circuits, a general-use snap switch suitable only for use on ac (not general-use ac—dc snap switches) where the motor full-load current rating is not more than 80 percent of the ampere rating of the switch

(3) A listed manual motor controller having a horsepower rating not less than the rating of the motor and marked "Suitable as Motor Disconnect"

(D) Autotransformer-Type Controlled Motors. For motors of over 2 hp to and including 100 hp, the separate disconnecting means required for a motor with an autotransformertype controller shall be permitted to be a general-use switch where all of the following provisions are met:

(1) The motor drives a generator that is provided with overload protection.

(2) The controller is capable of interrupting the locked-rotor current of the motors, is provided with a no voltage release, and is provided with running overload protection not exceeding 125 percent of the motor full-load current rating.

(3) Separate fuses or an inverse time circuit breaker rated or set at not more than 150 percent of the motor full-load current is provided in the motor branch circuit.

(E) Isolating Switches. For stationary motors rated at more than 40 hp dc or 100 hp ac, the disconnecting means shall be permitted to be a general-use or isolating switch where plainly marked "Do not operate under load."

(F) Cord-and-Plug-Connected Motors. For a cord-and-plug-connected motor, a horsepower-rated attachment plug and receptacle, flanged surface inlet and cord connector, or attachment plug and cord connector having ratings no less than the motor ratings shall be permitted to serve as the disconnecting means. Horsepower-rated attachment plugs, flanged surface inlets, receptacles, or cord connectors shall not be required for cord-and-plug-connected appliances in accordance with 422.33, room air conditioners in accordance with 440.63, or portable motors rated 1/3 hp or less.

(G) Torque Motors. For torque motors, the disconnecting means shall be permitted to be a general-use switch.

The (A) list is a closed list of seven. Two things people get wrong: (A)(6) is the modern — the "Suitable as Motor Disconnect" mark on a manual motor controller (the little red-handled switch you see on drive cabinets) — and when it sits on the line side of the 430.52(C)(5) fuses, those fuses are supplementary and real branch protection still goes upstream of the controller. And (A)(7) system isolation equipment is a 2017-era addition for drive systems: it goes on the load side of the overcurrent protection, and its own disconnecting means must be one of (A)(1)–(3).

(C) is the same 2× / 80% pair that article 41 used for the controller (430.83(C)) — the code lets the same general-use switch do double duty as controller and disconnect for ≤ 2 hp / 300 V motors. (E) is the big-motor isolating switch: above 40 hp dc / 100 hp ac you may use a plain "Do not operate under load" isolator, because at those sizes you are not expected to interrupt load current with it — you isolate dead equipment.

430.110 — Ampere Rating and Interrupting Capacity (115%, combined loads, the 2023 equation)

(A) General. The disconnecting means for motor circuits rated 1000 volts, nominal, or less shall have an ampere rating not less than 115 percent of the full-load current rating of the motor.

Exception: A listed unfused motor-circuit switch having a horsepower rating not less than the motor horsepower shall be permitted to have an ampere rating less than 115 percent of the full-load current rating of the motor.

(B) For Torque Motors. Disconnecting means for a torque motor shall have an ampere rating of at least 115 percent of the motor nameplate current.

(C) For Combination Loads. Where two or more motors are used together or where one or more motors are used in combination with other loads, such as resistance heaters, and where the combined load may be simultaneous on a single disconnecting means, the ampere and horsepower ratings of the combined load shall be determined as follows.

(1) Horsepower Rating. The rating of the disconnecting means shall be determined from the sum of all currents, including resistance loads, at the full-load condition and also at the locked-rotor condition. The combined full-load current and the combined locked-rotor current so obtained shall be considered as a single motor for the purpose of this requirement as follows. The full-load current equivalent to the horsepower rating of each motor shall be selected from Table 430.247, Table 430.248, Table 430.249, or Table 430.250. These full-load currents shall be added to the rating in amperes of other loads to obtain an equivalent full-load current for the combined load. The locked-rotor current equivalent to the horsepower rating of each motor shall be selected from Table 430.251 (A) or Table 430.251 (B). The locked-rotor currents shall be added to the rating in amperes of other loads to obtain an equivalent locked-rotor current for the combined load. Where two or more motors or other loads cannot be started simultaneously, the largest sum of locked-rotor currents of a motor or group of motors that can be started simultaneously and the full-load currents of other concurrent loads shall be permitted to be used to determine the equivalent locked-rotor current for the simultaneous combined loads. In cases where different current ratings are obtained when applying these tables, the largest value obtained shall be used. Exception: Where part of the concurrent load is resistance load, and where the disconnecting means is a switch rated in horsepower and amperes, the switch used shall be permitted to have a horsepower rating that is not less than the combined load of the motor(s), if the ampere rating of the switch is not less than the locked-rotor current of the motor(s) plus the resistance load.

(2) Ampere Rating. The ampere rating of the disconnecting means shall not be less than 115 percent of the sum of all currents at the full-load condition determined in accordance with 430.110(C)(1). Exception: A listed nonfused motor-circuit switch having a horsepower rating equal to or greater than the equivalent horsepower of the combined loads, determined in accordance with 430.110(C)(1), shall be permitted to have an ampere rating less than 115 percent of the sum of all currents at the full-load condition.

(3) Small Motors. For small motors not covered by Table 430.247, Table 430.248, Table 430.249, or Table 430.250, the locked-rotor current shall be assumed to be six times the full-load current.

Exception No. 1 to 430.110(C)(1) — NEW — in 2023, not in 2017 The locked-rotor current equivalent to the horsepower rating of each polyphase motor with design letter A shall be one of following: (1) If available, the motor's marked value of locked-rotor amperes (2) In the absence of a marked value of locked-rotor amperes for the motor, the value calculated from Equation 430.110(C)(1)a: I = 1000 × (kVA/hp) × hp ÷ (√3 × VLL), where: kVA/hp = maximum range value of kilovolt-amperes per horsepower with locked rotor in Table 430.7(B) associated with the motor's marked locked-rotor indicating code letter.

Informational Note: Equation 430.110(C)(1)a is obtained by solving for locked-rotor amperes in the formula for "kilovolt-amperes per horsepower with locked rotor," as follows (Equation 430.110(C)(1)b). The numerator of Equation 430.110(C)(1)b for kilovolt-amperes per horsepower is the apparent power input to a three-phase motor with locked rotor in units of volt-amperes. The factor of 1000 VA/kVA in the denominator converts this value to units of kilovolt-amperes and "marked value of rated horsepower" in the denominator converts this to kilovolt-amperes per horsepower. Note that "motor's marked value of rated volts" is a line-to-line value and "locked-rotor amperes" is a line value as opposed to a phase value.

430.111 — Switch or Circuit Breaker as Both Controller and Disconnecting Means

A switch or circuit breaker shall be permitted to be used as both the controller and disconnecting means if it complies with 430.111(A) and is one of the types specified in 430.111(B).

(A) General. The switch or circuit breaker complies with the requirements for controllers specified in 430.83, opens all ungrounded conductors to the motor, and is protected by an overcurrent device in each ungrounded conductor (which shall be permitted to be the branch-circuit fuses). The overcurrent device protecting the controller shall be permitted to be part of the controller assembly or shall be permitted to be separate. An autotransformer-type controller shall be provided with a separate disconnecting means.

(B) Type. The device shall be one of the types specified in 430.111(B)(1), (B)(2), or (B)(3).

(1) Air-Break Switch. An air-break switch, operable directly by applying the hand to a lever or handle.

(2) Inverse Time Circuit Breaker. An inverse time circuit breaker operable directly by applying the hand to a lever or handle. The circuit breaker shall be permitted to be both power and manually operable.

(3) Oil Switch. An oil switch used on a circuit whose rating does not exceed 1000 volts or 100 amperes, or by special permission on a circuit exceeding this capacity where under expert supervision. The oil switch shall be permitted to be both power and manually operable.

430.112 — Motors Served by Single Disconnecting Means

Each motor shall be provided with an individual disconnecting means.

Exception: A single disconnecting means shall be permitted to serve a group of motors under any one of the conditions of (a), (b), and (c). The single disconnecting means shall be rated in accordance with 430.110(C).

(a) Where a number of motors drive several parts of a single machine or piece of apparatus, such as metal- and woodworking machines, cranes, and hoists.

(b) Where a group of motors is under the protection of one set of branch-circuit protective devices as permitted by 430.53(A).

(c) Where a group of motors is in a single room within sight from the location of the disconnecting means.

430.113 — Energy from More Than One Source (the 2023 sign-content rule)

Motor and motor-operated equipment receiving electric energy from more than one source shall be provided with disconnecting means from each source of electric energy immediately adjacent to the equipment served. Each source shall be permitted to have a separate disconnecting means.

Where multiple disconnecting means are provided, a permanent warning sign shall be provided on or adjacent to each disconnecting means.

Exception No. 1: Where a motor receives electric energy from more than one source, the disconnecting means for the main power supply to the motor shall not be required to be immediately adjacent to the motor, provided that the controller disconnecting means is lockable in accordance with 110.25.

Exception No. 2: A separate disconnecting means shall not be required for a Class 2 remote-control circuit conforming with Article 725, rated not more than 30 volts, and isolated and ungrounded.

NEW — in 2023, not in 2017 …a permanent warning sign shall be provided on or adjacent to each disconnecting means indicating that multiple sources must be shut off to remove all power to the equipment. The sign at each disconnect shall identify the other specific circuits.

Also 2023: Exception No. 2 cites "Parts I and II of Article 725" (the 2017 text cites Article 725 generally, consistent with the 725/724 renumber of that era).

Typical case: a machine with utility power + a backup generator, or a VFD fed from two utility feeds. Each source gets its own disconnect at the equipment, and — since 2023 — each sign tells you which of the OTHER circuits also feeds the machine.

The edition history, verified line by line

Every body in Part IX (430.101–430.113) was word-level diffed, 2017 on-disk scan against the on-disk 2023 NEC CSV (verify_art42.py, 67 checks, all passing). The result:

• Two substantive changes (the verified 2017→2023 diffs): (1) new Exception No. 1 to 430.110(C)(1) — the design letter A locked-rotor rule with Equation 430.110(C)(1)a, the marked-LRA-preferred ladder, and its Informational Note derivation; the 2017 single exception becomes 2023's Exception No. 2. (2) 430.113 sign content — the two new sentences requiring the sign to state that multiple sources must be shut off and to identify the other specific circuits.
• Bookkeeping only, everywhere else: "controller" → "motor controller" (28 occurrences in 2023 Part IX vs 0 generic uses in 2017, where the term appears only in the device names "combination motor controller" and "manual motor controller"); all 2017 section subheadings ("Location.", "Operation.", "To Be Indicating.", "Type.", …) dropped in the 2023 print; 430.110's "ampere rating" → "current rating"; 430.102 exception items (a)/(b) → (1)/(2); 430.112 items (a)/(b)/(c) → (1)/(2)/(3); 430.102's "warning label" → "label".
• Reference edition moved: the 430.102(B) LOTO informational note cites NFPA 70E-2015 (2017) → NFPA 70E-2021 (2023).
• Every numeric value is unchanged 2017→2023: 1/8 hp (430.109(B)), 2 hp / 300 V (430.109(C)), 2× FLC, 80% (snap switch), over 2 hp to 100 hp (430.109(D)), 125% / 150% (430.109(D)(2)/(3)), 40 hp dc / 100 hp ac (430.109(E)), 1/3 hp (430.109(F)), 1000 V (430.110(A)/(E)), 115% (430.110(A)/(C)(2)), 6× (430.110(C)(3)), 30 V (430.113 E2), 1000 V / 100 A (430.111(B)(3)).
• The 430.106 gap: absent from BOTH the 2017 scan and the 2023 CSV (verified) — a genuine NEC numbering gap, not an extraction artifact. If a study guide cites "430.106", it is wrong for these editions.
• 2020 gap, disclosed honestly: the on-disk 2020 scan ends at Article 230, so no 2017→2020 word-diff is claimed for Part IX, and the edition of origin for the two additions cannot be pinned from the on-disk sources. Both are absent from the 2017 scan (verified) and present in the 2023 CSV (verified). This article therefore claims exactly: they are in the 2023 code and were not in the 2017 code — the 2017→2023 delta, verified on disk.

Worked examples (all computed by the shipped core under node)

Every number below comes from compute_art42.js run under node against the real shipped cores (nextStdBreaker, pickConductor31016) and the on-disk Table 430.248/430.250/430.251(A)/(B) full-load and locked-rotor values (2023 CSV, verbatim; the 2017 scan's table cells cross-verified by row-VA constancy in verify_art42.py). No hand math.

EX1 — 430.109(C): the ≤ 2 hp / 300 V switch paths, 1 hp single-phase 230 V

FLC from Table 430.248 (230 V column) = 8.0 A. The motor is inside (C)'s scope (1 ≤ 2 && 230 ≤ 300 = true). Path (C)(1): general-use switch ≥ 2 × 8.0 = 16.0 A → next standard 20 A. Path (C)(2): ac-only snap switch, FLC ≤ 80% of switch rating → switch ≥ 8.0 ÷ 0.80 = 10.0 A → 15 A (check: 80% × 15 = 12.0 A ≥ 8.0 A ✓). Path (C)(3): a listed manual motor controller ≥ 1 hp marked "Suitable as Motor Disconnect". The same switch that serves as the controller per 430.83(C) (article 41) also qualifies as the disconnect here. Conductors cross-reference (430.22): 125% × 8.0 = 10.0 A → 14 AWG Cu (75 °C or 60 °C column).

2 × 8.0 A = 16.0 A → 20 A switch · 8.0 ÷ 0.80 = 10.0 A → 15 A ac-only snap switch · conductors 10.0 A → 14 AWG Cu

EX2 — 430.110(A): the 115% rule, 5 hp three-phase 460 V

FLC from Table 430.250 (460 V column) = 7.6 A. Required current rating = 115% × 7.6 = 8.74 A → next standard 15 A disconnect (a 15 A motor-circuit switch or MCB). The Exception matters: a listed unfused motor-circuit switch hp-rated ≥ 5 hp may carry a current rating below 8.74 A — the hp mark is the rating that counts, which is why you see 5 hp switches with modest amperage marks. Conductors (430.22): 125% × 7.6 = 9.5 A → 14 AWG Cu (75 °C).

115% × 7.6 A = 8.74 A → 15 A disconnect · unfused hp-rated switch: 5 hp mark suffices · conductors 9.5 A → 14 AWG Cu

EX3 — 430.110(C)(1) + 430.112: one disconnect for three motors (the group rule)

A metalworking machine with 3 × 5 hp, three-phase, 460 V motors (design B/C/D), started simultaneously — 430.112(a) applies (they drive parts of a single machine). Per motor: FLC (Table 430.250, 460 V) = 7.6 A; LRA (Table 430.251(B), 460 V) = 46 A. Combined: FLC = 22.8 A, LRA = 138 A. Equivalent horsepower: the first 460 V table entry with FLC ≥ 22.8 A is 20 hp (27 A; 15 hp = 21 A is too small). Its LRA at 460 V = 145 A ≥ 138 A combined ✓. Ampere-rating path (430.110(C)(2)): 115% × 22.8 = 26.22 A → 30 A MCB/molded-case switch. Result: one 20 hp nonfused motor-circuit switch (460 V) — or a 30 A MCB (430.109(A)(2)).

3 × 7.6 A = 22.8 A FLC, 3 × 46 A = 138 A LRA → equivalent 20 hp (27 A ≥ 22.8 A; LRA 145 A ≥ 138 A) → one 20 hp switch, or 30 A (115% × 22.8 A = 26.22 A)

EX4 — 430.110(C)(1) Exception No. 1 [NEW 2023]: design letter A, no marked LRA

A 25 hp, three-phase, 460 V motor with design letter A (Table 430.7(B) range 0–3.14 kVA/hp, so kVA/hp = 3.14) — no marked locked-rotor amperes — in combination with a 10 A resistance heater on the same disconnect. Equation 430.110(C)(1)a: I_LR = 1000 × 3.14 × 25 ÷ (√3 × 460) = 78,500 ÷ 796.75 = 98.5 A. Compare: Table 430.251(B) (B/C/D only) would give 183 A at 25 hp / 460 V — the design A fallback is 0.54× that, which is the point: design A motors have low inrush. Combined: FLC = 34.0 A (Table 430.250) + 10 A = 44.0 A; LRA = 98.5 + 10 = 108.5 A. (C)(2): 115% × 44.0 = 50.6 A → 60 A disconnect. Exception No. 2 path (hp+ampere-rated nonfused switch): hp rating ≥ 25 hp AND ampere rating ≥ 108.5 A → a 25+ hp / 110 A nonfused switch. In the 2017 code this calculation had no defined LRA for the unmarked design A motor — Table 430.251(B) covers B/C/D only, and the 2017 exception (resistance-load, now No. 2) did not supply one.

I_LR = 1000 × 3.14 × 25 ÷ (1.7321 × 460) = 98.5 A · combined 44.0 A FLC / 108.5 A LRA → 60 A disconnect (115% × 44.0 A = 50.6 A), or 25+ hp / 110 A nonfused switch

EX5 — 430.111(B)(2): one breaker does all three jobs

5 hp three-phase 460 V, FLC = 7.6 A. Branch OCPD (430.52, inverse time): 250% × 7.6 = 19.0 A → 20 A. One 20 A, 3-pole inverse time circuit breaker operable by hand on a lever: branch OCPD (430.52) + controller (430.83(A)(2)) + disconnecting means (430.111(B)(2)) — provided it opens all ungrounded conductors and complies with 430.83 (430.111(A)). The 430.109(A)(2) "listed molded case circuit breaker" entry is the same device read from the type list.

250% × 7.6 A = 19.0 A → 20 A 3-pole inverse CB = OCPD + controller + disconnect

EX6 — 430.109(D): the autotransformer general-use-switch path, 50 hp 460 V

A 50 hp, three-phase, 460 V motor with an autotransformer controller is inside (D)'s scope (2 < 50 ≤ 100 = true). Its separate motor disconnect may be a plain general-use switch only if all three conditions hold: (1) the motor drives a generator with overload protection; (2) the controller interrupts locked-rotor current, has a no-voltage release, and running overload ≤ 125% of FLC (125% × 65 A = 81.25 A); (3) separate fuses or an inverse CB in the branch circuit rated ≤ 150% × 65 A = 97.5 A → 100 A max. Miss any one condition and 430.111(A)'s last sentence applies: an autotransformer-type controller shall be provided with a separate disconnecting means of the (A) types.

150% × 65 A = 97.5 A → 100 A fuse/CB cap (all 3 conditions met → general-use switch OK as motor disconnect; else (A)-type disconnect required)

EX7 — 430.109(F): the cord-and-plug boundary (the OCR-garbled values, clean)

The values the 2017 scan garbled, with the clean 2023 numbers and their context: a cord-and-plug-connected motor uses a horsepower-rated attachment plug/receptacle, flanged surface inlet and cord connector, or attachment plug and cord connector, ratings ≥ the motor's ratings. Not required for 422.33 appliances, 440.63 room air conditioners, or portable motors ≤ 1/3 hp (the scan printed "% hp"). Boundary: 1/3 hp 230 V = 3.6 A FLC (exempt — a standard 15 A cord suffices), 1/2 hp 230 V = 4.9 A (one step up — the hp-rated plug is required).

≤ 1/3 hp portable: standard cord · 1/2 hp: hp-rated plug/receptacle or flanged inlet (3.6 A → 4.9 A across the boundary)

EX8 — 430.103 + 430.105: the 2-pole disconnect with one pole in the grounded conductor

A 2-pole switch disconnecting a 120 V single-phase motor, one pole in the permanently grounded conductor, is legal if (a) it opens all ungrounded conductors with no pole operable independently (430.103), (b) it cannot close automatically (430.103), and (c) the grounded-conductor pole cannot open without simultaneously opening all circuit conductors (430.105). The design condition (c) is mechanical: a 2-pole switch where the neutral pole can throw alone is a code violation even though "one pole in the grounded conductor" is textually permitted.

2-pole, pole in grounded conductor: legal only if mechanically tied (430.105) + no independent pole operation + no auto-close (430.103)

Gotchas

• 430.106 does not exist. The Part IX sequence skips from 430.105 to 430.107 in both 2017 and 2023 (verified on disk). Study guides citing "430.106" are wrong for these editions.
• "In sight from the motor" is not "in sight from the machinery." Both. 430.102(B)(1) requires sight of the motor location AND the driven machinery location. A disconnect visible from the motor but behind a wall from where the operator stands fails. This is why the disconnect usually ends up at the machine's operating position, not next to the starter.
• The lockable-110.25 exceptions are the 2023-era workaround for big motors. 430.102(B)(2) exception: no separate motor disconnect when the controller disconnect is lockable, where a motor-disconnect location is impracticable/added-hazard (the code names >100 hp, submersibles, adjustable-speed drives, classified locations) or in industrial installations with written safety procedures (70E LOTO). The 70E edition cited moved 2015 → 2021 between code editions.
• The 115% rule uses the TABLE FLC, not the nameplate. 430.110(A) says "full-load current rating of the motor" — the same table-value convention as 430.22. A nameplate 7.5 A motor on the 7.6 A table row is a 7.6 A calculation. (Torque motors are the exception: 115% of nameplate current, 430.110(B).)
• The unfused-hp-switch exception is the escape hatch from 115%. "Listed unfused motor-circuit switch having a horsepower rating not less than the motor horsepower" (430.110(A) Exception, repeated in (C)(2) Exception for combined loads). Fused switches get no such pass.
• 430.251(B) is a B/C/D table — design A motors are not in it. The table's own note: "Design A motors are not limited to a maximum starting current or locked rotor current." That is exactly the gap the 2023 Exception No. 1 fills with Equation 430.110(C)(1)a — and it is the reason an unmarked design A motor in a combined-load calculation had no defined LRA in 2017.
• Equation 430.110(C)(1)a uses the MAX of the code-letter range. For design A that is 3.14 kVA/hp (top of 0–3.14) — not the middle, not a typical value. And "marked value of rated volts" is line-to-line; the resulting amperes are a LINE value, per the 2023 Informational Note.
• The 2023 430.113 sign is prescriptive now. Pre-2023, "a permanent warning sign" had no required content. 2023: the sign must say multiple sources must be shut off AND identify the other specific circuits. On a 2-source machine that means two signs, each naming the other feed.
• An autotransformer controller can NEVER be its own disconnect. 430.111(A) last sentence: "An autotransformer-type controller shall be provided with a separate disconnecting means." 430.109(D) only relaxes what device that separate disconnect may be (a general-use switch, under three conditions) — it never removes the requirement.
• 430.108 sweeps every disconnect in the circuit. Two disconnects = both must pass 430.109 + 430.110. You cannot hide a non-compliant device as "just the second one".
• The 2017 scan's OCR mangled 7 spots in Part IX — 430.109(B) "% Horsepower" (= 1/8), 430.109(E) "40 hp de" (= dc), 430.109(F) "% hp" (= 1/3), 430.109(A)(5) "self. protected" (= self-protected), 430.109(A)(6) "control: lers" (= controllers), 430.113 "1s lockable" (= is), 430.102 "ave met" (= are). All corrected above and in the verbatim blockquotes, each cross-confirmed against the clean 2023 CSV and checked by audit_art42_verbatim.py; the corrections are also disclosed in each section's source note. The 2017 scan's line-wrap hyphenation (e.g. "discon-necting", "control- lers") is normalized throughout without being called out as an "error" — that's typesetting, not OCR corruption. If you study from the 2017 print, trust the 2023 text where they disagree.

The method, step by step

1. Locate the disconnect(s) per 430.102: controller disconnect in sight of the controller (A); motor disconnect in sight of motor AND machinery (B)(1) — or the controller disconnect doubles (B)(2) if in sight of both. Check the lockable-110.25 exceptions (omission of the motor disconnect) for >100 hp / submersible / ASD / classified / industrial-qualified-persons cases.
2. Choose the device per 430.109: one of the seven (A) types by default. Small motors: (B) 1/8 hp → branch OCPD; (C) ≤ 2 hp / 300 V → 2× FLC general-use switch, 80% ac-only snap switch, or marked manual controller; (D) 2–100 hp autotransformer → general-use switch if the 3 conditions hold; (E) > 40 hp dc / 100 hp ac → isolating switch marked "Do not operate under load"; (F) cord-and-plug → hp-rated plug (except ≤ 1/3 hp portable etc.); (G) torque → general-use switch. (EX1, EX6, EX7.)
3. Rate it per 430.110: single motor: 115% of table FLC (A) — except an unfused hp-rated switch; torque: 115% of nameplate (B). Combined loads: sum FLCs (+ resistance loads) and sum LRAs (Tables 430.251(A)/(B), or the 2023 equation for unmarked design A, or 6× for sub-table small motors); equivalent-hp lookup in the FLC tables; 115% of the FLC sum (C)(2). (EX2, EX3, EX4.)
4. Consider the single-device path (430.111): air-break switch, inverse time CB, or oil switch (1000 V / 100 A) as OCPD + controller + disconnect in one — with an OCPD in each ungrounded conductor. Never for autotransformer controllers. (EX5.)
5. Multi-source? (430.113): a disconnect at the equipment for EACH source; since 2023, each sign states that all sources must be shut off and identifies the other specific circuits; lockable controller disconnect excuses the main-power location; Class 2 ≤ 30 V isolated remote-control feeds need no separate disconnect.
6. Sweep check (430.103/430.104/430.105/430.107/430.108): opens all ungrounded conductors, no independent pole, no auto-close, indicating, ≥ one readily accessible, and EVERY disconnect in the circuit compliant.
7. Size the rest of the circuit elsewhere: conductors per 430.22 (article 38), OCPD per 430.52 (article 38), overload per 430.32 (article 39), controller per Part VII (article 41). Part IX is only the disconnect.

FAQ