---
id:
aliases:
  - nec-440
tags:
  - authorship/other
  - destiny/uncertain
  - exclude-from-word-count
  - status/draft
  - topic/construction/electrical
  - type/media/reference
title: Article 440 Air-Conditioning and Refrigerating Equipment
---
# Article 440 Air-Conditioning and Refrigerating Equipment

## Part I. General

### 440.1 Scope.

This article applies to electric motor-driven air-conditioning and refrigerating equipment and to the branch circuits and controllers for such equipment. It provides for the special considerations necessary for circuits supplying hermetic refrigerant motor-compressors and for any air-conditioning or refrigerating equipment that is supplied from a branch circuit that supplies a hermetic refrigerant motor-compressor.

#### 440.2 Definitions.

The definitions in this section shall apply only within this article.

##### Branch-Circuit Selection Current.

The value in amperes to be used instead of the rated-load current
in determining the ratings of motor branch-circuit conductors,
disconnecting means, controllers,
and branch-circuit short-circuit and ground-fault protective devices
wherever the running overload protective device permits a sustained current
greater than the specified percentage of the rated-load current.
The value of branch-circuit selection current
will always be equal to or greater than the marked rated-load current.

##### Leakage-Current Detector-Interrupter (LCDI).

A device provided in a power supply cord or cord set
that senses leakage current flowing between or from the cord conductors
and interrupts the circuit at a predetermined level of leakage current.

##### Rated-Load Current.

The current of a hermetic refrigerant motor-compressor
resulting when it is operated at the rated load,
rated voltage, and rated frequency
of the equipment it serves.

### 440.3 Other Articles.

#### 440.3(A) Article 430.

These provisions are in addition to, or amendatory of,
the provisions of [[nfpa-70_430_motors|Article 430]]
and other articles in this Code,
which apply except as modified in this article.

#### 440.3(B) Articles 422, 424, or 430.

The rules of Articles [[nfpa-70_422_appliances|422]],
[[nfpa-70_424|424]], or [[nfpa-70_430_motors|430]], as applicable,
shall apply to air-conditioning and refrigerating equipment
that does not incorporate a hermetic refrigerant motor-compressor.
This equipment includes devices
that employ refrigeration compressors driven by conventional motors,
furnaces with air-conditioning evaporator coils installed,
fan-coil units, remote forced air-cooled condensers,
remote commercial refrigerators, and so forth.

#### 440.3(C) Article 422.

Equipment such as room air conditioners,
household refrigerators and freezers,
drinking water coolers, and beverage dispensers
shall be considered appliances,
and [[nfpa-70_422_appliances|Article 422]] shall also apply.

#### 440.3(D) Other Applicable Articles.

Hermetic refrigerant motor-compressors,
circuits, controllers, and equipment
shall also comply with the applicable provisions of Table 440.3(D).

##### Table 440.3(D) Other Articles

| Equipment/Occupancy                                                                                                                                                                    | Article                                  | Section |
| -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------- | ------- |
| Capacitors                                                                                                                                                                             |                                          | 460.9   |
| Commercial garages, aircraft hangars, motor fuel dispensing facilities, bulk storage plants, spray application, dipping, and coating processes, and inhalation anesthetizing locations | 511, 513, 514, 515, 516, and 517 Part IV |         |
| Hazardous (classified) locations                                                                                                                                                       | 500--503, 505, and 506                   |         |
| Motion picture and television studios and similar locations                                                                                                                            | 530                                      |         |
| Resistors and reactors                                                                                                                                                                 | 470                                      |         |

### 440.4 Marking on Hermetic Refrigerant Motor-Compressors and Equipment.

#### 440.4(A) Hermetic Refrigerant Motor-Compressor Nameplate.

A hermetic refrigerant motor-compressor shall be provided with a nameplate
that shall indicate the manufacturer's name, trademark, or symbol;
identifying designation; phase; voltage; and frequency.
The rated-load current in amperes of the motor-compressor
shall be marked by the equipment manufacturer
on either or both the motor-compressor nameplate
and the nameplate of the equipment in which the motor-compressor is used.
The locked-rotor current
of each single-phase motor-compressor having a rated-load current
of more than 9 amperes at 115 volts, or more than 4.5 amperes at 230 volts,
and each polyphase motor-compressor
shall be marked on the motor-compressor nameplate.
Where a thermal protector complying with 440.52(A)(2) and (B)(2) is used,
the motor-compressor nameplate or the equipment nameplate
shall be marked with the words "thermally protected."
Where a protective system complying with 440.52(A)(4) and (B)(4)
is used and is furnished with the equipment,
the equipment nameplate shall be marked with the words,
"thermally protected system."
Where a protective system complying with 440.52(A)(4) and (B)(4) is specified,
the equipment nameplate shall be appropriately marked.

#### 440.4(B) Multimotor and Combination-Load Equipment.

Multimotor and combination-load equipment shall be provided with a visible nameplate marked with the maker's name, the rating in volts, frequency and number of phases, minimum supply circuit conductor ampacity, the maximum rating of the branch-circuit short-circuit and ground-fault protective device, and the short-circuit current rating of the motor controllers or industrial control panel. The ampacity shall be calculated by using Part IV and counting all the motors and other loads that will be operated at the same time. The branch-circuit short-circuit and ground-fault protective device rating shall not exceed the value calculated by using Part III. Multimotor or combination-load equipment for use on two or more circuits shall be marked with the above information for each circuit.

> [!important] Exception No. 1:
> Multimotor and combination-load equipment that is suitable under the provisions of this article for connection to a single 15- or 20-ampere, 120-volt, or a 15-ampere, 208- or 240-volt, single-phase branch circuit shall be permitted to be marked as a single load.

> [!important] Exception No. 2:
> The minimum supply circuit conductor ampacity and the maximum rating of the branch-circuit short-circuit and ground-fault protective device shall not be required to be marked on a room air conditioner complying with 440.62(A).

> [!important] Exception No. 3:
> Multimotor and combination-load equipment used in one- and two-family dwellings or cord-and-attachment-plug-connected equipment shall not be required to be marked with a short-circuit current rating.

#### 440.4(C) Branch-Circuit Selection Current.

A hermetic refrigerant motor-compressor, or equipment containing such a compressor,
having a protection system that is approved for use with the motor-compressor that it protects
and that permits continuous current in excess of the specified percentage
of nameplate rated-load current given in 440.52(B)(2) or (B)(4)
shall also be marked with a branch-circuit selection current
that complies with 440.52(B)(2) or (B)(4).
This marking shall be provided by the equipment manufacturer
and shall be on the nameplate(s) where the rated-load current(s) appears.

### 440.5 Marking on Controllers.

A controller shall be marked with the manufacturer's name, trademark, or symbol; identifying designation; voltage; phase; full-load and locked-rotor current (or horsepower) rating; and other data as may be needed to properly indicate the motor-compressor for which it is suitable.

### 440.6 Ampacity and Rating.

The size of conductors for equipment covered by this article
shall be selected from Table 310.16 through Table 310.19
or calculated in accordance with 310.14 as applicable.
The required ampacity of conductors and rating of equipment
shall be determined according to 440.6(A) and 440.6(B).

#### 440.6(A) Hermetic Refrigerant Motor-Compressor.

For a hermetic refrigerant motor-compressor,
the rated-load current marked on the nameplate of the equipment in which the motor compressor is employed
shall be used in determining the rating or ampacity of the disconnecting means,
the branch-circuit conductors, the controller,
the branch-circuit short-circuit and ground-fault protection,
and the separate motor overload protection.
Where no rated load current is shown on the equipment nameplate,
the rated-load current shown on the compressor nameplate shall be used.

> [!important] Exception No. 1:
> Where so marked, the branch-circuit selection current shall be used instead of the rated-load current to determine the rating or ampacity of the disconnecting means, the branch-circuit conductors, the controller, and the branch-circuit short-circuit and ground-fault protection.

> [!important] Exception No. 2:
> For cord-and-plug-connected equipment, the nameplate marking shall be used in accordance with 440.22(B), Exception No. 2.

#### 440.6(B) Multimotor Equipment.

For multimotor equipment employing a shaded-pole
or permanent split-capacitor-type fan or blower motor,
the full-load current for such motor
marked on the nameplate of the equipment in which the fan or blower motor is employed
shall be used instead of the horsepower rating
to determine the ampacity or rating of the disconnecting means,
the branch-circuit conductors, the controller,
the branch-circuit short-circuit and ground-fault protection,
and the separate overload protection.
This marking on the equipment nameplate
shall not be less than the current marked on the fan or blower motor nameplate.

### 440.7 Highest Rated (Largest) Motor.

In determining compliance with this article and with 430.24, 430.53(B) and 430.53(C), and 430.62(A), the highest rated (largest) motor shall be considered to be the motor that has the highest rated-load current. Where two or more motors have the same highest rated load-current, only one of them shall be considered as the highest rated (largest) motor. For other than hermetic refrigerant motor-compressors, and fan or blower motors as covered in 440.6(B), the full-load current used to determine the highest rated motor shall be the equivalent value corresponding to the motor horsepower rating selected from Table 430.248, Table 430.249, or Table 430.250.

> [!important] Exception:
> Where so marked, the branch-circuit selection current shall be used instead of the rated-load current in determining the highest rated (largest) motor-compressor.

### 440.8 Single Machine.

An air-conditioning or refrigerating system
shall be considered to be a single machine
under the provisions of [[nfpa-70_430_motors#^87-ex1|430.87, Exception No. 1]],
and [[nfpa-70_430_motors#^112-ex|430.112, Exception]].
The motors shall be permitted to be located remotely from each other.

### 440.9 Grounding and Bonding.

Where equipment is installed outdoors on a roof, an equipment grounding conductor of the wire type shall be installed in outdoor portions of metallic raceway systems that use compression-type fittings.

### 440.10 Short-Circuit Current Rating.

#### 440.10(A) Installation.

Motor controllers or industrial control panels of multimotor and combination-load equipment shall not be installed where the available fault current exceeds its short-circuit current rating as marked in accordance with [[#440.4(B) Multimotor and Combination-Load Equipment.|440.4(B)]].

#### 440.10(B) Documentation.

When motor controllers or industrial control panels of multimotor and combination-load equipment are required to be marked with a short circuit current rating, the available fault current and the date the available fault current calculation was performed shall be documented and made available to those authorized to inspect, install, or maintain the installation.

## Part II. Disconnecting Means

### 440.11 General.

Part II is intended to require disconnecting means capable of disconnecting air-conditioning and refrigerating equipment, including motor-compressors and controllers from the circuit conductors.

### 440.12 Rating and Interrupting Capacity.

#### 440.12(A) Hermetic Refrigerant Motor-Compressor.

A disconnecting means serving a hermetic refrigerant motor-compressor shall be selected on the basis of the nameplate rated-load current or branch-circuit selection current, whichever is greater, and locked-rotor current, respectively, of the motor-compressor as follows.

##### 440.12(A)(1) Ampere Rating.

The ampere rating shall be at least 115 percent of
the nameplate rated-load current
or branch-circuit selection current,
whichever is greater.

> [!important] Exception:
> A listed unfused motor circuit switch, without fuseholders, having a horsepower rating not less than the equivalent horsepower determined in accordance with 440.12(A)(2) shall be permitted to have an ampere rating less than 115 percent of the specified current.

##### 440.12(A)(2) Equivalent Horsepower.

To determine the equivalent horsepower
in complying with the requirements of [[nfpa-70_430_motors#430.109 Type.|430.109]],
the horsepower rating shall be selected from
[[nfpa-70_430_motors#^t248|Table 430.248]],
[[nfpa-70_430_motors#^t249|Table 430.249]],
or [[nfpa-70_430_motors#^t250|Table 430.250]]
corresponding to the rated-load current or branch-circuit selection current, whichever is greater,
and also the horsepower rating from [[nfpa-70_430_motors#^t251a|Table 430.251(A)]]
or [[nfpa-70_430_motors#^t251b|Table 430.251(B)]]
corresponding to the locked-rotor current.
In case the nameplate rated-load current or branch-circuit selection current and locked-rotor current
do not correspond to the currents shown in Table 430.248, Table 430.249,
Table 430.250, Table 430.251(A), or Table 430.251(B),
the horsepower rating corresponding to the next higher value shall be selected.
In case different horsepower ratings are obtained when applying these tables,
a horsepower rating at least equal to the larger of the values obtained shall be selected.

#### 440.12(B) Combination Loads.

Where the combined load of two or more hermetic refrigerant motor-compressors or one or more hermetic refrigerant motor-compressor with other motors or loads may be simultaneous on a single disconnecting means, the rating for the disconnecting means shall be determined in accordance with 440.12(B)(1) and (B)(2).

##### 440.12(B)(1) Horsepower Rating.

The horsepower rating of the disconnecting means shall be determined from the sum of all currents, including resistance loads, at the rated-load condition and also at the locked-rotor condition. The combined rated-load current and the combined locked-rotor current so obtained shall be considered as a single motor for the purpose of this requirement as required by 440.12(B)(1)(a) and (B)(1)(b).

* (a) The full-load current equivalent to the horsepower rating of each motor, other than a hermetic refrigerant motor-compressor, and fan or blower motors as covered in 440.6(B) shall be selected from Table 430.248, Table 430.249, or Table 430.250. These full-load currents shall be added to the motor-compressor rated-load current(s) or branch-circuit selection current(s), whichever is greater, and to the rating in amperes of other loads to obtain an equivalent full-load current for the combined load.

* (b) The locked-rotor current equivalent to the horsepower rating of each motor, other than a hermetic refrigerant motor-compressor, shall be selected from Table 430.251(A) or Table 430.251(B), and, for fan and blower motors of the shaded-pole or permanent split-capacitor type marked with the locked-rotor current, the marked value shall be used. The locked-rotor currents shall be added to the motor-compressor locked-rotor current(s) and 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 such as resistance heaters, or both, cannot be started simultaneously, appropriate combinations of locked-rotor and rated-load current or branch-circuit selection current, whichever is greater, shall be an acceptable means of determining the equivalent locked-rotor current for the simultaneous combined load.

> [!important] Exception:
> Where part of the concurrent load is a resistance load and the disconnecting means is a switch rated in horsepower and amperes, the switch used shall be permitted to have a horsepower rating not less than the combined load to the motor-compressor(s) and other motor(s) at the locked-rotor condition, if the ampere rating of the switch is not less than this locked-rotor load plus the resistance load.

##### 440.12(B)(2) Full-Load Current Equivalent.

The ampere rating of the disconnecting means shall be at least 115 percent
of the sum of all currents at the rated-load condition determined in accordance with 440.12(B)(1).

> [!important] Exception:
> A listed unfused motor circuit switch, without fuseholders, having a horsepower rating not less than the equivalent horsepower determined by 440.12(B)(1) shall be permitted to have an ampere rating less than 115 percent of the sum of all currents.

#### 440.12(C) Small Motor-Compressors.

For small motor-compressors not having the locked-rotor current marked on the nameplate, or 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 rated-load current.

#### 440.12(D) Disconnecting Means.

Every disconnecting means in the refrigerant motor-compressor circuit between the point of attachment to the feeder and the point of connection to the refrigerant motor-compressor shall comply with the requirements of 440.12.

#### 440.12(E) Disconnecting Means Rated in Excess of 100 Horsepower.

Where the rated-load or locked-rotor current as determined above would indicate a disconnecting means rated in excess of 100 hp,
430.109(E) shall apply.

### 440.13 Cord-Connected Equipment.

For cord-connected equipment such as room air conditioners, household refrigerators and freezers, drinking water coolers, and beverage dispensers, a separable connector or an attachment plug and receptacle shall be permitted to serve as the disconnecting means.

> [!info] Informational Note:
> For room air conditioners, see 440.63.

### 440.14 Location.

Disconnecting means shall be located within sight from, and readily accessible from the air-conditioning or refrigerating equipment. The disconnecting means shall be permitted to be installed on or within the air-conditioning or refrigerating equipment.

The disconnecting means shall not be located on panels that are designed to allow access to the air-conditioning or refrigeration equipment or to obscure the equipment nameplate(s).

> [!important] Exception No. 1:
> Where the disconnecting means provided in accordance with 430.102(A) is lockable in accordance with 110.25 and the refrigerating or air-conditioning equipment is essential to an industrial process in a facility with written safety procedures, and where the conditions of maintenance and supervision ensure that only qualified persons service the equipment, a disconnecting means within sight from the equipment shall not be required.

> [!important] Exception No. 2:
> Where an attachment plug and receptacle serve as the disconnecting means in accordance with 440.13, their location shall be accessible but shall not be required to be readily accessible.

> [!info] Informational Note No. 1:
> See Parts VII and IX of Article 430 for additional requirements.

> [!info] Informational Note No. 2:
> See 110.26.

## Part III. Branch-Circuit Short-Circuit and Ground-Fault Protection

### 440.21 General.

Part III specifies devices intended to protect the branch-circuit conductors, control apparatus, and motors in circuits supplying hermetic refrigerant motor-compressors against overcurrent due to short circuits and ground faults. They are in addition to or amendatory of

Article 240.

### 440.22 Application and Selection.

#### 440.22(A) Rating or Setting for Individual Motor-Compressor.

The motor-compressor branch-circuit short-circuit and ground-fault protective device shall be capable of carrying the starting current of the motor. A protective device having a rating or setting not exceeding 175 percent of the motor-compressor rated-load current or branch-circuit selection current, whichever is greater, shall be permitted, provided that, where the protection specified is not sufficient for the starting current of the motor, the rating or setting shall be permitted to be increased but shall not exceed 225 percent of the motor rated-load current or branch-circuit selection current, whichever is greater.

> [!important] Exception:
> The rating of the branch-circuit short-circuit and ground-fault protective device shall not be required to be less than 15 amperes.

#### 440.22(B) Rating or Setting for Equipment.

The equipment branch-circuit short-circuit and ground-fault protective device shall be capable of carrying the starting current of the equipment. Where the hermetic refrigerant motor-compressor is the only load on the circuit, the protection shall comply with 440.22(A).

Where the equipment incorporates more than one hermetic refrigerant motor-compressor or a hermetic refrigerant motor-compressor and other motors or other loads, the equipment short-circuit and ground-fault protection shall comply with 430.53 and 440.22(B)(1) and
(B)(2).

##### 440.22(B)(1) Motor-Compressor Largest Load.

Where a hermetic refrigerant motor-compressor is the largest load connected to the circuit, the rating or setting of the branch-circuit short-circuit and ground-fault protective device shall not exceed the value specified in 440.22(A) for the largest motor-compressor plus the sum of the rated-load current or branch-circuit selection current, whichever is greater, of the other motor-compressor(s) and the ratings of the other loads supplied.

##### 440.22(B)(2) Motor-Compressor Not Largest Load.

Where a hermetic refrigerant motor-compressor is not the largest load connected to the circuit, the rating or setting of the branch-circuit short-circuit and ground-fault protective device shall not exceed a value equal to the sum of the rated-load current or branch-circuit selection current, whichever is greater, rating(s) for the motor-compressor(s) plus the value specified in 430.53(C)(4) where other motor loads are supplied, or the value specified in 240.4 where only nonmotor loads are supplied in addition to the motor-compressor(s).

> [!important] Exception No. 1:
> Equipment that starts and operates on a 15- or 20-ampere 120-volt, or 15-ampere 208- or 240-volt single-phase branch circuit, shall be permitted to be protected by the 15- or 20-ampere overcurrent device protecting the branch circuit, but if the maximum branch-circuit short-circuit and ground-fault protective device rating marked on the equipment is less than these values, the circuit protective device shall not exceed the value marked on the equipment nameplate.

> [!important] Exception No. 2:
> The nameplate marking of cord-and-plug-connected equipment rated not greater than 250 volts, single-phase, such as household refrigerators and freezers, drinking water coolers, and beverage dispensers, shall be used in determining the branch-circuit requirements, and each unit shall be considered as a single motor unless the nameplate is marked otherwise.

#### 440.22(C) Protective Device Rating Not to Exceed the Manufacturer's Values.

Where maximum protective device ratings shown on a manufacturer's overload relay table for use with a motor controller are less than the rating or setting selected in accordance with 440.22(A) and (B), the protective device rating shall not exceed the manufacturer's values marked on the equipment.

## Part IV. Branch-Circuit Conductors

### 440.31 General.

Part IV and Article 310 specify ampacities of conductors required to carry the motor current without overheating under the conditions specified, except as modified in 440.6(A), Exception No. 1.

These articles shall not apply to integral conductors of motors, to motor controllers and the like, or to conductors that form an integral part of approved equipment.

### 440.32 Single Motor-Compressor.

Branch-circuit conductors supplying a single motor-compressor shall have an ampacity not less than the greater of:

* (1) 125 percent of the motor-compressor rated-load current

* (2) 125 percent of the branch-circuit selection current

For a wye-start, delta-run connected motor-compressor, the selection of branch-circuit conductors between the controller and the motor-compressor shall be permitted to be based on 72 percent of either the motor-compressor rated-load current or the branch-circuit selection current, whichever is greater.

> [!info] Informational Note:
> The individual motor circuit conductors of wye-start, delta-run connected motor-compressors carry 58 percent of the rated load current. The multiplier of 72 percent is obtained by multiplying 58 percent by 1.25.

### 440.33 Motor-Compressor(s) With or Without Additional Motor Loads.

Conductors supplying one or more motor-compressor(s) with or without an additional motor load(s) shall have an ampacity not less than the sum of each of the following:

* (1) The sum of the rated-load or branch-circuit selection current, whichever is greater, of all motor-compressor(s)

* (2) The sum of the full-load current rating of all other motors

* (3) 25 percent of the highest motor-compressor or motor full load current in the group

> [!important] Exception No. 1:
> Where the circuitry is interlocked so as to prevent the starting and running of a second motor-compressor or group of motor-compressors, the conductor size shall be determined from the largest motor-compressor or group of motor-compressors that is to be operated at a given time.

> [!important] Exception No. 2:
> The branch-circuit conductors for room air conditioners shall be in accordance with Part VII of Article 440.

### 440.34 Combination Load.

Conductors supplying a motor-compressor load in addition to other load(s) as calculated from Article 220 and other applicable articles shall have an ampacity sufficient for the other load(s) plus the required ampacity for the motor-compressor load determined in accordance with 440.33 or, for a single motor-compressor, in accordance with 440.32.

> [!important] Exception:
> Where the circuitry is interlocked so as to prevent simultaneous operation of the motor-compressor(s) and all other loads connected, the conductor size shall be determined from the largest size required for the motor-compressor(s) and other loads to be operated at a given time.

### 440.35 Multimotor and Combination-Load Equipment.

The ampacity of the conductors supplying multimotor and combination-load equipment shall not be less than the minimum circuit ampacity marked on the equipment in accordance with 440.4(B).

## Part V. Controllers for Motor-Compressors

### 440.41 Rating.

#### 440.41(A) Motor-Compressor Controller.

A motor-compressor controller shall have both a continuous-duty full-load current rating and a locked-rotor current rating not less than the nameplate rated-load current or branch-circuit selection current, whichever is greater, and locked-rotor current, respectively, of the compressor. In case the motor controller is rated in horsepower but is without one or both of the foregoing current ratings, equivalent currents shall be determined from the ratings as follows. Table 430.248, Table 430.249, and Table 430.250 shall be used to determine the equivalent full-load current rating. Table 430.251(A) and Table 430.251(B) shall be used to determine the equivalent locked-rotor current ratings.

#### 440.41(B) Controller Serving More Than One Load.

A controller serving more than one motor-compressor or a motor-compressor and other loads shall have a continuous-duty full-load current rating and a locked-rotor current rating not less than the combined load as determined in accordance with 440.12(B).

## Part VI. Motor-Compressor and Branch-Circuit Overload Protection

### 440.51 General.

Part VI specifies devices intended to protect the motor-compressor, the motor-control apparatus, and the branch-circuit conductors against excessive heating due to motor overload and failure to start.

> [!info] Informational Note:
> See 240.4(G) for application of Parts III and VI of Article 440.

### 440.52 Application and Selection.

#### 440.52(A) Protection of Motor-Compressor.

Each motor-compressor shall be protected against overload and failure to start by one of the following means:

* (1) A separate overload relay that is responsive to motor-compressor current. This device shall be selected to trip at not more than
140 percent of the motor-compressor rated-load current.

* (2) A thermal protector integral with the motor-compressor, approved for use with the motor-compressor that it protects on the basis that it will prevent dangerous overheating of the motor-compressor due to overload and failure to start. If the current-interrupting device is separate from the motor-compressor and its control circuit is operated by a protective device integral with the motorcompressor, it shall be arranged so that the opening of the control circuit will result in interruption of current to the motorcompressor.(3) A fuse or inverse time circuit breaker responsive to motor current, which shall also be permitted to serve as the branch-circuit short-circuit and ground-fault protective device. This device shall be rated at not more than 125 percent of the motor-compressor rated-load current. It shall have sufficient time delay to permit the motor-compressor to start and accelerate its load. The equipment or the motor-compressor shall be marked with this maximum branch-circuit fuse or inverse time circuit breaker rating.

* (4) A protective system, furnished or specified and approved for use with the motor-compressor that it protects on the basis that it will prevent dangerous overheating of the motor-compressor due to overload and failure to start. If the current-interrupting device is separate from the motor-compressor and its control circuit is operated by a protective device that is not integral with the current-interrupting device, it shall be arranged so that the opening of the control circuit will result in interruption of current to the motor-compressor.

#### 440.52(B) Protection of Motor-Compressor Control Apparatus and Branch-Circuit Conductors.

The motor-compressor controller(s), the disconnecting means, and the branch-circuit conductors shall be protected against overcurrent due to motor overload and failure to start by one of the following means, which shall be permitted to be the same device or system protecting the motor-compressor in accordance with 440.52(A):

> [!important] Exception:
> Overload protection of motor-compressors and equipment on 15- and 20-ampere, single-phase, branch circuits shall be permitted to be in accordance with 440.54 and 440.55.

* (1) An overload relay selected in accordance with 440.52(A) (1)

* (2) A thermal protector applied in accordance with 440.52(A)(2), that will not permit a continuous current in excess of 156 percent of the marked rated-load current or branch-circuit selection current

* (3) A fuse or inverse time circuit breaker selected in accordance with 440.52(A)(3)

* (4) A protective system, in accordance with 440.52(A)(4), that will not permit a continuous current in excess of 156 percent of the marked rated-load current or branch-circuit selection current

### 440.53 Overload Relays.

Overload relays and other devices for motor overload protection that are not capable of opening short circuits shall be protected by fuses or inverse time circuit breakers with ratings or settings in accordance with Part III unless identified for group installation or for partwinding motors and marked to indicate the maximum size of fuse or inverse time circuit breaker by which they shall be protected.

> [!important] Exception:
> The fuse or inverse time circuit breaker size marking shall be permitted on the nameplate of the equipment in which the overload relay or other overload device is used.
440.54 Motor-Compressors and Equipment on 15- or 20-Ampere Branch Circuits --- Not Cord- and

Attachment-Plug-Connected.

Overload protection for motor-compressors and equipment used on 15- or 20-ampere 120-volt, or 15-ampere 208- or 240-volt singlephase branch circuits as permitted in Article 210 shall be permitted as indicated in 440.54(A) and 440.54(B).

#### 440.54(A) Overload Protection.

The motor-compressor shall be provided with overload protection selected as specified in 440.52(A). Both the controller and motor overload protective device shall be identified for installation with the short-circuit and ground-fault protective device for the branch circuit to which the equipment is connected.

#### 440.54(B) Time Delay.

The short-circuit and ground-fault protective device protecting the branch circuit shall have sufficient time delay to permit the motorcompressor and other motors to start and accelerate their loads.
440.55 Cord- and Attachment-Plug-Connected Motor-Compressors and Equipment on 15- or 20-Ampere

Branch Circuits.

Overload protection for motor-compressors and equipment that are cord- and attachment-plug-connected and used on 15- or 20ampere
120-volt, or 15-ampere 208- or 240-volt, single-phase branch circuits as permitted in Article 210 shall be permitted as indicated in 440.55(A), (B), and (C).

#### 440.55(A) Overload Protection.

The motor-compressor shall be provided with overload protection as specified in 440.52(A). Both the controller and the motor overload protective device shall be identified for installation with the short-circuit and ground-fault protective device for the branch circuit to which the equipment is connected.

#### 440.55(B) Attachment Plug and Receptacle or Cord Connector Rating.

The rating of the attachment plug and receptacle or cord connector shall not exceed 20 amperes at 125 volts or 15 amperes at
250 volts.

#### 440.55(C) Time Delay.

The short-circuit and ground-fault protective device protecting the branch circuit shall have sufficient time delay to permit the motorcompressor and other motors to start and accelerate their loads.

## Part VII. Provisions for Room Air Conditioners

### 440.60 General.

Part VII shall apply to electrically energized room air conditioners that control temperature and humidity. For the purpose of Part VII, a room air conditioner (with or without provisions for heating) shall be considered as an ac appliance of the air-cooled window, console, or in-wall type that is installed in the conditioned room and that incorporates a hermetic refrigerant motor-compressor(s). Part VII covers equipment rated not over 250 volts, single phase, and the equipment shall be permitted to be cord- and attachment-plug-connected.

A room air conditioner that is rated 3-phase or rated over 250 volts shall be directly connected to a wiring method recognized in

Chapter 3, and Part VII shall not apply.

### 440.61 Grounding.

The enclosures of room air conditioners shall be connected to the equipment grounding conductor in accordance with 250.110,
250.112, and 250.114.

### 440.62 Branch-Circuit Requirements.

#### 440.62(A) Room Air Conditioner as a Single Motor Unit.

A room air conditioner shall be considered as a single motor unit in determining its branch-circuit requirements where all the following conditions are met:

* (1) It is cord- and attachment-plug-connected.

* (2) Its rating is not more than 40 amperes and 250 volts, single phase.

* (3) Total rated-load current is shown on the room air-conditioner nameplate rather than individual motor currents.

* (4) The rating of the branch-circuit short-circuit and ground-fault protective device does not exceed the ampacity of the branchcircuit conductors or the rating of the receptacle, whichever is less.

#### 440.62(B) Where No Other Loads Are Supplied.

The total marked rating of a cord- and attachment-plug-connected room air conditioner shall not exceed 80 percent of the rating of a branch circuit where no other loads are supplied.

#### 440.62(C) Where Lighting Units or Other Appliances Are Also Supplied.

The total marked rating of a cord- and attachment-plug-connected room air conditioner shall not exceed 50 percent of the rating of a branch circuit where lighting outlets, other appliances, or general-use receptacles are also supplied. Where the circuitry is interlocked to prevent simultaneous operation of the room air conditioner and energization of other outlets on the same branch circuit, a cord- and attachment-plug-connected room air conditioner shall not exceed 80 percent of the branch-circuit rating.

### 440.63 Disconnecting Means.

An attachment plug and receptacle or cord connector shall be permitted to serve as the disconnecting means for a single-phase room air conditioner rated 250 volts or less if (1) the manual controls on the room air conditioner are readily accessible and located within
1.8 m (6 ft) of the floor, or (2) an approved manually operable disconnecting means is installed in a readily accessible location within sight from the room air conditioner.

### 440.64 Supply Cords.

Where a flexible cord is used to supply a room air conditioner, the length of such cord shall not exceed 3.0 m (10 ft) for a nominal, 120volt rating or 1.8 m (6 ft) for a nominal, 208- or 240-volt rating.

### 440.65 Protection Devices.

Single-phase cord- and plug-connected room air conditioners shall be provided with one of the following factory-installed devices:

* (1) Leakage-current detector-interrupter (LCDI)

* (2) Arc-fault circuit interrupter (AFCI)

* (3) Heat detecting circuit interrupter (HDCI)

The protection device shall be an integral part of the attachment plug or be located in the power supply cord within 300 mm (12 in.) of the attachment plug.
